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Linus Walleij0dd71e92006-05-04 18:47:07 +00001Building and Installing
2-----------------------
Linus Walleij6fd2f082006-03-28 07:19:22 +00003
Linus Walleij0dd71e92006-05-04 18:47:07 +00004See the "INSTALL" file.
5
6
Linus Walleij3f7529c2010-07-24 20:33:41 +00007Initiator and Responder
8-----------------------
9
10libmtp implements an MTP initiator, which means it initiate
11MTP sessions with devices. The devices responding are known
12as MTP responders. libmtp runs on something with a USB host
13controller interface, using libusb to access the host
14controller.
15
16If you're more interested in the MTP responders, gadgets like
17MP3 players, mobile phones etc, look into MeeGo:s Buteo Sync:
18http://wiki.meego.com/Buteo - these guys are creating a fully
19open source MTP responder.
20
21
Linus Walleij0dd71e92006-05-04 18:47:07 +000022Heritage
23--------
24
25libmtp is based on several ancestors:
26
27* libptp2 by Mariusz Woloszyn was the starting point used
28 by Richard A. Low for the initial starter port. You can
29 find it at http://libptp.sourceforge.net/
30
31* libgphoto2 by Mariusz Woloszyn and Marcus Meissner was
32 used at a later stage since it was (is) more actively
33 maintained. libmtp tracks the PTP implementation in
34 libgphoto2 and considers it an upstream project. We will
35 try to submit anything generally useful back to libgphoto2
36 and not make double efforts. In practice this means we
37 use ptp.c, ptp.h and ptp-pack.c verbatim from the libgphoto2
38 source code. If you need to change things in these files,
39 make sure it is so general that libgphoto2 will want to
40 merge it to their codebase too. You find libgphoto2 as part
41 of gPhoto: http://gphoto.sourceforge.net/
42
43* libnjb was a project that Richard and Linus were working
Linus Walleijfcf88912006-06-05 13:23:33 +000044 on before libmtp. When Linus took Richards initial port
Linus Walleij0dd71e92006-05-04 18:47:07 +000045 and made an generic C API he re-used the philosophy and
46 much code from libnjb. Many of the sample programs are for
47 example taken quite literally from libnjb. You find it here:
48 http://libnjb.sourceforge.net/
49
50
Linus Walleijea7d45b2009-02-23 22:26:09 +000051Contacting and Contributing
52---------------------------
53
54See the project page at http://libmtp.sourceforge.net/
55We always need your help. There is a mailinglist and a
56bug report system there.
57
58People who want to discuss MTP devices in fora seem to
59hang out on the forums at AnythingbutiPod:
60http://www.anythingbutipod.com/forum/
61
62
Linus Walleij0dd71e92006-05-04 18:47:07 +000063Compiling programs for libmtp
64-----------------------------
65
66libmtp has support for the pkg-config script by adding a libmtp.pc
67entry in $(prefix)/lib/pkgconfig. To compile a libmtp program,
68"just" write:
69
70gcc -o foo `pkg-config --cflags --libs libmtp` foo.c
71
72This also simplifies compilation using autoconf and pkg-config: just
73write e.g.
74
75PKG_CHECK_MODULES(MTP, libmtp)
76AC_SUBST(MTP_CFLAGS)
77AC_SUBST(MTP_LIBS)
78
79To have libmtp LIBS and CFLAGS defined. Needless to say, this will
80only work if you have pkgconfig installed on your system, but most
81people have nowadays.
82
83If your library is installed in e.g. /usr/local you may have to tell
84this to pkgconfig by setting the PKG_CONFIG_PATH thus:
85
86export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
87
88
89Documentation
90-------------
91
92Read the API documentation that can be generated with doxygen.
93It will be output in doc/html if you have Doxygen properly
94installed. (It will not be created unless you have Doxygen!)
95
96For information about the Media Transfer Protocol, see:
97http://en.wikipedia.org/wiki/Media_Transfer_Protocol
98
Linus Walleij7a83e552008-07-29 21:30:43 +000099The official 1.0 specification for MTP was released by the
100USB Implementers Forum in may, 2008. Prior to this, only a
101proprietary Microsoft version was available, and quite a few
102devices out there still use some aspects of the Microsoft
103version, which deviates from the specified standard. You can
104find the official specification here:
105http://www.usb.org/developers/devclass_docs/MTP_1.0.zip
Linus Walleij0dd71e92006-05-04 18:47:07 +0000106
Linus Walleij1b91ca62008-10-17 07:07:56 +0000107
108The Examples
109------------
110
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000111In the subdirectory "examples" you find a number of
Linus Walleij1b91ca62008-10-17 07:07:56 +0000112command-line tools, illustrating the use of libmtp in very
113simple terms.
114
115Please do not complain about the usability or documentation
116of these examples, they look like they do for two reasons:
117
1181. They are examples, not tools. If they were intended for
119 day-to-day usage by commandline freaks, I would have
120 called them "tools" not "examples".
121
1222. The MTP usage paradigm is that a daemon should hook
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000123 the device upon connection, and that it should be
Linus Walleij1b91ca62008-10-17 07:07:56 +0000124 released by unplugging. GUI tools utilizing HAL (hald)
125 and D-Bus do this much better than any commandline
126 program ever can. (See below on bugs.) Specificationwise
127 this is a bug, however it is present in many, many
128 devices.
129
130That said, if you want to pick up and maintain the examples,
131please volunteer.
132
133
Linus Walleijc36e2a62011-12-29 21:31:49 +0100134FAQ: Common Problems
135--------------------
136
137Some MTP devices have strange pecularities. We try to work around
138these whenever we can, sometimes we cannot work around it or we
139cannot test your solution.
140
141* mtp-* tools doesn't work because someone else is already hogging
142 the device
143
144 This is a common problem, the most common case could be that
145 gphoto2 (which can also talk PTP/MTP) is taking over the device
146 as soon as it's plugged in. Some distributions are configured that
147 way. Counter it like this:
148
149 gvfs-mount -s gphoto2
150
151 Then re-attach the device.
152
Linus Walleij5fff17e2012-07-18 23:49:05 +0200153 Sometimes the "gvfs-gphoto2-volume-monitor" is running on the
154 system and hogging the device, try something like:
155
Linus Walleijfb807262012-08-18 22:31:45 +0200156 pkill gfvs-gphoto2-volume-monitor
Linus Walleij5fff17e2012-07-18 23:49:05 +0200157
Linus Walleijfb807262012-08-18 22:31:45 +0200158 Then plug in the device and issue "mtp-detect" to figure out if
159 this may be the case.
Linus Walleij5fff17e2012-07-18 23:49:05 +0200160
Linus Walleijc36e2a62011-12-29 21:31:49 +0100161* Generic MTP/PTP disconnect misbehaviour: we have noticed that
162 Windows Media Player apparently never close the session to an MTP
163 device. There is a daemon in Windows that "hooks" the device
164 by opening a PTP session to any MTP device, whenever it is
165 plugged in. This daemon proxies any subsequent transactions
166 to/from the device and will never close the session, thus
167 Windows simply does not close sessions at all.
168
Linus Walleije962add2012-01-13 20:22:22 +0100169 For example this means that a device may work the first time
170 you run some command-line example like "mtp-detect" while
171 subsequent runs fail.
172
Linus Walleijc36e2a62011-12-29 21:31:49 +0100173 Typical sign of this illness: broken pipes on closing sessions,
174 on the main transfer pipes(s) or the interrupt pipe:
175
176 Closing session
177 usb_clear_halt() on INTERRUPT endpoint: Broken pipe
178 OK.
179
180 This means that device manufacturers doesn't notice any problems
181 with devices that do not correctly handle closing PTP/MTP
182 sessions, since Windows never do it. The proper way of closing
183 a session in Windows is to unplug the device, simply put.
184
185 Since libmtp actually tries to close sessions, some devices
186 may fail since the close session functionality has never been
187 properly tested, and "it works with Windows" is sort of the
188 testing criteria at some companies.
189
Linus Walleije962add2012-01-13 20:22:22 +0100190 You can get Windows-like behaviour on Linux by running a udev-aware
Linus Walleijc36e2a62011-12-29 21:31:49 +0100191 libmtp GUI client like Rhythmbox or Gnomad2, which will "hook"
192 the device when you plug it in, and "release" it if you unplug
Linus Walleije962add2012-01-13 20:22:22 +0100193 it, and you start/end you transfer sessions by plugging/unplugging
194 the USB cable.
195
196 The "Unix way" of running small programs that open the device,
197 do something, then close the device, isn't really working with
198 such devices and you cannot expect to have command line tools
199 like the mtp examples work with them. You could implement new
200 example programs that just call to a mediating daemon like the
201 Windows MTP stack does. (And change all programs using libmtp
202 directly today.)
Linus Walleijc36e2a62011-12-29 21:31:49 +0100203
204 If this bug in your device annoys you, contact your device
205 manufacturer and ask them to test their product with some libmtp
206 program.
207
Linus Walleijf9424812012-06-27 22:16:57 +0200208* Android locked screen: some devices just report zero files
209 and no storages when the device is locked, probably so as not
210 to allow the MTP access to be used as a "backdoor" into the
211 device. Unlock the device before listing files, set the autolock
212 to some large value or disabled if it disturbs you, you are
213 causing this to yourself.
214
Linus Walleijf776f7b2012-06-06 10:14:05 +0200215* Samsung Android 2.3.x devices: these have a special MTP stack
216 with some specific bugs that we have maybe nailed down now.
217 It suffers from an "immediate connect" syndrome, i.e. you have
218 to connect to the device within 7 seconds of plugging in, or it
219 will go numb. This also goes for command-line activity with
220 the example programs, so this device is better used with a
221 GUI tool like Rhythmbox, gnomad2...
222
Linus Walleijc36e2a62011-12-29 21:31:49 +0100223* Generic USB misbehaviour: some devices behave badly under MTP
224 and USB mass storage alike, even down to the lowest layers
225 of USB. You can always discuss such issues at the linux-usb
226 mailing list if you're using Linux:
227 http://www.linux-usb.org/mailing.html
228
229 If you have a problem specific to USB mass storage mode, there
230 is a list of strange behaving devices in the Linux kernel:
231 http://lxr.linux.no/linux/drivers/usb/storage/unusual_devs.h
232 You can discuss this too on the mentioned list, for understanding
233 the quirks, see:
234 http://www2.one-eyed-alien.net/~mdharm/linux-usb/target_offenses.txt
235
236* Generic certificate misbehaviour. All devices are actually
237 required to support a device certificate to be able to
238 encrypt Windows Media (WMA/WMV) files. However there are
239 obviously a lot of devices out there which doesn't support
240 this at all but instead crash. Typical printout:
241
242 Error 2: PTP Layer error 02ff: get_device_unicode_property(): failed
243 to get unicode property.
244
245 This should only affect "mtp-detect", there is no other
246 application currently retrieveing the certificate (not that we
247 know anyway).
248
249* Kernel bug on Linux. Linux 2.6.16 is generally speaking required
250 to use any MTP device under USB 2.0. This is because the EHCI
251 driver previously did not support zero-length writes to endpoints.
252 It should work in most cases however, or if you connect it
253 to an UHCI/OHCI port instead (yielding lower speed). But
254 please just use a recent kernel.
255
256* Zen models AVI file seeking problem: the Zens cannot parse the
257 files for the runlength metadata. Do not transfer file with e.g.
258 mtp-sendfile, use mtp-sendtr and set the length of the track to
259 the apropriate number of seconds and it will work. In graphical
260 clients, use a "track transfer" function to send these AVI files,
261 the Zens need the metadata associated with tracks to play back
262 movies properly. Movies are considered "tracks" in the MTP world.
263
264* Some devices that disregard the metadata sent with the MTP
265 commands will parse the files for e.g. ID3 metadata. Some still
266 of these devices expect only ID3v2.3 metadata and will fail with
267 a modern ID3v2,4 tag writer, like many of those found in Linux
268 applications. Windows Media Player use ID3v2.3 only, so many
269 manufacturers only test this version.
270
271* The Zen Vision:M (possibly more Creative Zens) has a firmware bug
272 that makes it drop the last two characters off a playlist name.
273 It is fixed in later firmware.
274
275* For Creative Technology devices, there are hard limits on how
276 many files can be put onto the device. For a 30 GiB device (like
277 the Zen Xtra) the limit is 6000, for a 60 GiB device the limit
278 is 15000 files. For further Creative pecularities, see the
279 FAQ sections at www.nomadness.net.
280
281* Sandisk sansa c150 and probably several other Sandisk devices
282 (and possibly devices from other manufacturers) have a dual
283 mode with MTP and USB mass storage. The device will initially
284 claim to be mass storage so udev will capture is and make the
285 use of MTP mode impossible. One way of avoiding it could be to
286 be to blacklist the "usb-storage" module in
287 /etc/modprobe.c/blacklist with a row like this:
288 "blacklist usb-storage". Some have even removed the
289 "usb-storage.ko" (kernel module file) to avoid loading.
290
291* Sandisk Sansa Fuze has three modes: auto, MTP or mass storage
292 (MSC). Please set it to MTP to avoid problems with libmtp.
293
294* The iriver devices (possibly all of them) cannot handle the
295 enhanced GetObjectPropList MTP command (0x9805) properly. So
296 they have been banned from using it.
297
298* iriver devices have problems with older versions of libmtp and
299 with new devices libmtp does not know of as of yet, since it
300 has an oldstyle USB device controller that cannot handle zero
301 writes. (Register your device with us!) All their devices are
302 likely to need a special device flag in the src/libusb-glue.c
303 database.
304
305* The Samsung Yepp T9 has several strange characteristics, some
306 that we've managed to work around. (For example it will return
307 multiple PTP packages in a single transaction.)
308
309* The early firmware for Philips HDD players is known to be
310 problematic. Please upgrade to as new firmware as you can get.
311 (Yes this requires some kind of Windows Installation I think.)
312
313* Philips HDD 1630/16 or 1630/17 etc may lock themselves up,
314 turning inresponsive due to internal corruption. This typically
315 gives an error in opening the PTP session. Apparently you can
316 do a "repair" with the firmware utility (Windows only) which
317 will often fix this problem and make the device responsive
318 again.
319
320* Some devices that implement GetObjectPropList (0x9805) will
321 not return the entire object list if you request a list for object
322 0xffffffffu. (But they should.) So they may need the special
323 DEVICE_FLAG_BROKEN_MTPGETOBJPROPLIST_ALL.
324
325* Some (smaller) subset of devices cannot even get all the
326 properties for a single object in one go, these need the
327 DEVICE_FLAG_BROKEN_MTPGETOBJPROPLIST. Currently only the
328 iriver devices seem to have this bug.
329
330* The Toshiba Gigabeat S (and probably its sibling the
331 Microsoft Zune and other Toshiba devices) will only display
332 album information tags for a song in case there is also
333 an abstract album (created with the album interface) with
334 the exact same name.
335
336* The Zen Vision:M has an older firmware which is very corrupt,
337 it is incompatible with the Linux USB stack altogether. The
338 kernel dmesg will look something like this, and you have to
339 upgrade the firmware using Windows:
340 usb 4-5: new high speed USB device using ehci_hcd and address 5
341 usb 4-5: configuration #1 chosen from 1 choice
342 usb 4-5: can't set config #1, error -110
343
344* The Sirus Stiletto does not seem to allow you to copy any files
345 off the device. This may be someone's idea of copy protection.
346
347* The Samsung P2 assigns parent folder ID 0 to all unknown file
348 types.(i.e. moves them to the root folder)
349
350* The Sandisk Sansa Clip+ needs a firmware upgrade in earlier
351 versions in order to work properly.
352
353
Linus Walleija1b66f22007-05-10 20:02:16 +0000354New Devices
355-----------
356
Linus Walleijfcf88912006-06-05 13:23:33 +0000357If you happen upon a device which libmtp claims it cannot
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000358autodetect, please submit the vendor ID and device ID
Linus Walleij9ee29402007-10-31 20:24:48 +0000359(these can be obtained from the "lsusb" and "lsusb -n"
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000360commands run as root) as a bug, patch or feature request
361on the Sourceforge bug tracker at our homepage. If it
362gives a sensible output from "mtp-detect" then please attach
363the result as well as it teach us some stuff about your
364device. If you've done some additional hacking, join our
Linus Walleij9ee29402007-10-31 20:24:48 +0000365mailinglist and post your experiences there.
Linus Walleijda558be2007-03-10 21:42:25 +0000366
Linus Walleija1b66f22007-05-10 20:02:16 +0000367If you want to be able to hack some more and you're not
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000368afraid of C hacking, add an entry for your device's
369vendor/product ID and a descriptive string to the database
Linus Walleij6dc01682007-11-15 21:23:46 +0000370in the file src/music-players.h.
Linus Walleija1b66f22007-05-10 20:02:16 +0000371
372If you want to poke around to see if your device has some
373special pecularities, you can test some special device
Linus Walleij6dc01682007-11-15 21:23:46 +0000374flags (defined in src/device-flags.h) by inserting them
375together with your device entry in src/music-players.h.
Linus Walleija1b66f22007-05-10 20:02:16 +0000376Flags can be tested in isolation or catenated with "|"
377(binary OR). If relatives to your device use a certain
378flag, chances are high that a new device will need it
379too, typically from the same manufacturer.
380
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000381The most common flag that needs to be set is the
Linus Walleija1b66f22007-05-10 20:02:16 +0000382DEVICE_FLAG_UNLOAD_DRIVER that detach any Linux kernel
383drivers that may have attached to the device making
Linus Walleij94f23d52007-08-04 19:37:28 +0000384MTP access impossible. This is however not expected to
385really work: this is a problem being tracked as of
386now (2007-08-04). See the "last resort" solutions below
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000387if you really need to get your dual-mode device to work
Linus Walleij94f23d52007-08-04 19:37:28 +0000388with MTP.
Linus Walleija1b66f22007-05-10 20:02:16 +0000389
Linus Walleijcc2cf972007-11-22 20:23:43 +0000390Another flag which is easy to identify is the
391DEVICE_FLAG_NO_ZERO_READS, which remedies connection
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000392timeouts when getting files, and some timeouts on e.g.
Linus Walleijcc2cf972007-11-22 20:23:43 +0000393successive "mtp-connect" calls.
394
Linus Walleija1b66f22007-05-10 20:02:16 +0000395If your device is very problematic we are curious of how it
Linus Walleijda558be2007-03-10 21:42:25 +0000396works under Windows, so we enjoy reading USB packet sniffs
397that reveal the low-level traffic carried out between
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000398Windows Media Player and your device. This can be done
Linus Walleij61c25682007-09-04 14:46:21 +0000399using e.g.:
400
401* USBsnoop:
402 http://benoit.papillault.free.fr/usbsnoop/
403
404* The trial version of HHD Softwares software-only
405 USB monitor. You need to get a copy of version 2.37 since
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000406 the newer trial versions won't let you carry out the
Linus Walleij61c25682007-09-04 14:46:21 +0000407 needed packet sniffs. (As of 2007-03-10 a copy can be found
408 at: http://www.cobbleware.com/files/usb-monitor-237.exe)
409
Linus Walleijda558be2007-03-10 21:42:25 +0000410There are other USB monitors as well, some more expensive
411alternatives use hardware and even measure electronic
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000412characteristics of the traffic (which is far too much
Linus Walleijda558be2007-03-10 21:42:25 +0000413detail for us).
414
Linus Walleij91fb0282007-09-03 21:16:08 +0000415Device sniffs are an easy read since the PTP/MTP protocol
416is nicely structured. All commands will have a structure such
417as this in the log, we examplify with a object list request:
418
419PTP REQEUST:
420000120: Bulk or Interrupt Transfer (UP), 03.09.2007 12:49:25.9843750 +0.0
421Pipe Handle: 0x863ce234 (Endpoint Address: 0x2)
422Send 0x20 bytes to the device:
423 20 00 00 00 01 00 05 98 23 00 00 00 27 03 00 10 ......?#...'...
424 Length TYPE CMD Trans# Param1
425
426 00 00 00 00 02 DC 00 00 00 00 00 00 00 00 00 00 .....Ü..........
427 Param2 Param3 Param4 Param5
428
429[OPTIONAL] DATA PHASE:
430000121: Bulk or Interrupt Transfer (UP), 03.09.2007 12:49:26.0 +0.0156250
431Pipe Handle: 0x863ce214 (Endpoint Address: 0x81)
432Get 0x1a bytes from the device:
433 1A 00 00 00 02 00 05 98 23 00 00 00 01 00 00 00 .......?#.......
434 Length TYPE CMD Trans# DATA
435
436 27 03 00 10 02 DC 04 00 00 30 '....Ü...0
437
438RESPONSE:
439000122: Bulk or Interrupt Transfer (UP), 03.09.2007 12:49:26.0 +0.0
440Pipe Handle: 0x863ce214 (Endpoint Address: 0x81)
441Get 0xc bytes from the device:
442 0C 00 00 00 03 00 01 20 23 00 00 00 ....... #...
443 Length TYPE CODE Trans#
444
445* One send (OUT to the device), two reads (IN from the device).
446
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000447* All three byte chunks commands are
448 sent/recieved/recieeved by the function ptp_transaction()
Linus Walleij91fb0282007-09-03 21:16:08 +0000449 in the file ptp.c.
450
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000451* It boils down to ptp_usb_sendreq(), optionally ptp_usb_senddata()
452 or ptp_usb_getdata() and finally ptp_usb_getresp() in the file
Linus Walleij91fb0282007-09-03 21:16:08 +0000453 libusb-glue.c. Notice ptp_usb_sendreq() and ptp_usb_getresp()
454 are ALWAYS called. The TYPE field correspond to this, so the
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000455 TYPES in this case are "COMMAND" (0x0001), "DATA" (0x0002),
Linus Walleij91fb0282007-09-03 21:16:08 +0000456 and "RESPONSE" (0x0003).
457
458* Notice that the byte order is little endian, so you need to read
459 each field from right to left.
460
461* This COMMAND has:
462 CMD 0x99805, we see in ptp.h that this is PTP_OC_MTP_GetObjPropList.
463 Transaction# 0x00000023.
464 REQUEST parameters 0x10000327, 0x00000000, 0x0000DC02, 0x00000000
465 0x00000000, in this case it means "get props for object 0x10000327",
466 "any format", "property 0xDC02" (PTP_OPC_ObjectFormat), then two
467 parameters that are always zero (no idea what they mean or their
468 use).
469
470* The DATA has:
471 CMD 0x99805, we see in ptp.h that this is PTP_OC_MTP_GetObjPropList.
472 Transaction# 0x00000023.
473 Then comes data 0x00000001, 0x10000327, 0xDC02, 0x0004, 0x3000
474 Which means in this case, (and this is the tricky part) "here
475 you have 1 property", "for object 0x10000327", "it is property
476 0xDC02" (PTP_OPC_ObjectFormat), "which is of type 0x0004"
477 (PTP_DTC_UINT16), "and set to 0x3000" (PTP_OFC_Undefined, it
478 is perfectly valid to have undefined object formats, since it
479 is a legal value defining this).
480
481* This RESPONSE has:
482 CMD 0x99805, we see in ptp.h that this is PTP_OC_MTP_GetObjPropList.
483 Return Code ("RC") = 0x2001, PTP_RC_OK, all went fine.
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000484 Transaction# 0x00000023.
Linus Walleijfcf88912006-06-05 13:23:33 +0000485
Linus Walleijd05fce62007-09-29 20:17:23 +0000486If you want to compare the Windows behaviour with a similar
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000487operation using libmtp you can go into the src/libusb-glue.c
Linus Walleij6dc01682007-11-15 21:23:46 +0000488file and uncomment the row that reads:
Linus Walleijd05fce62007-09-29 20:17:23 +0000489
490//#define ENABLE_USB_BULK_DEBUG
491
492(I.e. remove the two //.)
493
494This will make libmtp print out a hex dump of every bulk USB
495transaction. The bulk transactions contain all the PTP/MTP layer
496data, which is usually where the problems appear.
497
Linus Walleij6fd2f082006-03-28 07:19:22 +0000498
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200499Notes to assist with debugging new devices:
500-------------------------------------------
501
Linus Walleijc36e2a62011-12-29 21:31:49 +0100502In debugging new hardware, we highly recommend that you only
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200503use the example mtp-* applications that come with libmtp, as other
504applications may have their own bugs that may interfere with your
505new device working correctly. Using another application instead of
506those that come with libmtp just adds another point of failure.
507
508For debugging, there are 3 main options:
509
Linus Walleijc36e2a62011-12-29 21:31:49 +01005101. Use the env variable: LIBMTP_DEBUG to increase the
511verboseness of the debugging output for any application using
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200512libmtp. Relevant codes are:
513* 0x00 [0000 0000] : no debug (default)
514* 0x01 [0000 0001] : PTP debug
515* 0x02 [0000 0010] : Playlist debug
516* 0x04 [0000 0100] : USB debug
517* 0x08 [0000 1000] : USB data debug
518// Codes are hex and binary respectively. Simple add them togther
519// to get your desired level of output.
520
521(Assuming bash)
Linus Walleijc36e2a62011-12-29 21:31:49 +0100522eg:
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200523$ export LIBMTP_DEBUG=12
524$ mtp-detect
525 // To get USB debug and USB data debug information.
526
527$ export LIBMTP_DEBUG=2
528$ mtp-detect
529 // To get Playlist debug information.
Linus Walleijc36e2a62011-12-29 21:31:49 +0100530
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200531Also note, an application may also use the LIBMTP_debug() API
532function to achieve the same options as listed above.
533
Linus Walleijc36e2a62011-12-29 21:31:49 +01005342. Use "strace" on the various mtp-* commands to see where/what
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200535is falling over or getting stuck at.
536* On Solaris and FreeBSD, use "truss" or "dtrace" instead on "strace".
537* On Mac OS X, use "ktrace" or "dtrace" instead of "strace".
538* On OpenBSD and NetBSD, use "ktrace" instead of "strace".
539
540This will at least help pinpoint where the application is failing, or
Linus Walleijc36e2a62011-12-29 21:31:49 +0100541a device is reporting incorrect information. (This is extremely helpful
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200542with devices that have odd disconnection requirements).
543
Linus Walleijc36e2a62011-12-29 21:31:49 +0100544The use of these tools may also pinpoint issues with libusb as
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200545implemented by each OS vendor or issues with the MTP implementation
546on the new device as well, so please be prepared for either case.
547
5483. Use "gdb" or similar debugger to step through the code as it is
549run. This is time consuming, and not needed just to pinpoint where
Linus Walleijc36e2a62011-12-29 21:31:49 +0100550the fault is.
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200551
Linus Walleijc36e2a62011-12-29 21:31:49 +0100552The use of gdb or another debugger may also miss or actually cause
553command and data timing issues with some devices, leading to false
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200554information. So please consider this a last resort option.
555
556Also please read the "It's Not Our Bug!" section below, as it does
557contain some useful information that may assist with your device.
558
559
Linus Walleij8d799eb2009-07-23 22:58:06 +0000560Dual-mode devices does not work - last resort:
561----------------------------------------------
Linus Walleijbd7624c2007-05-28 10:48:54 +0000562
563Some devices that are dual-mode are simply impossible to get
564to work under Linux because the usb-storage(.ko) kernel
565module hook them first, and refuse to release them, even
Linus Walleij94f23d52007-08-04 19:37:28 +0000566when we specify the DEVICE_FLAG_UNLOAD_DRIVER flag. (Maybe
567it DOES release it but the device will immediately be probed
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000568at the USB mass storage interface AGAIN because it
Linus Walleij94f23d52007-08-04 19:37:28 +0000569enumerates.)
Linus Walleijbd7624c2007-05-28 10:48:54 +0000570
Linus Walleij8d799eb2009-07-23 22:58:06 +0000571Here is what some people do:
572
573 1. Plug in the device.
574 2. USB-mass storage folder will open automatically.
575 3. Unmount the device.
576 4. Run mtp-detect. It will most likely fail the first time.
577 5. Run mtp-detect again, it might work this time, or fail. Keep running
578 till it works. 99% it works by the third try.
579 6. Once mtp-detect gives you an "Ok", open either Rhythmbox or Gnomad2,
580 everything should work.
581
Linus Walleije20abaf2007-12-10 11:20:34 +0000582Linux: Try this, if you have a recent 2.6.x Linux kernel,
Linus Walleij584eb8d2007-09-05 19:51:27 +0000583run (as root) something like:
584
585> rmmod usb_storage ; mtp-detect
586
587You can run most any command or a client like gnomad2 or
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000588Amarok immediately after the rmmod command. This works
Linus Walleij584eb8d2007-09-05 19:51:27 +0000589sometimes. Another way:
Linus Walleijbd7624c2007-05-28 10:48:54 +0000590
Linus Walleij94f23d52007-08-04 19:37:28 +0000591* Edit /etc/modprobe.d/blacklist
Linus Walleijbd7624c2007-05-28 10:48:54 +0000592
593* Add the line "blacklist usb-storage"
594
595* Reboot.
596
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000597Now none of you USB disks, flash memory sticks etc will be
Linus Walleijbd7624c2007-05-28 10:48:54 +0000598working (you just disabled them all). However you *can* try
599your device, and it might have started working because there
600is no longer a USB mass storage driver that tries to hook onto
601the mass storage interface of your device.
602
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000603If not even blacklisting works (check with
Linus Walleij94f23d52007-08-04 19:37:28 +0000604"lsmod | grep usb-storage"), there is some problem with
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000605something else and you may need to remove or rename the file
Linus Walleij94f23d52007-08-04 19:37:28 +0000606/lib/modules/<VERSION>/kernel/drivers/usb/storage/usb-storage.ko
607manually.
608
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000609If you find the PerfectSolution(TM) to this dilemma, so you
Linus Walleijbd7624c2007-05-28 10:48:54 +0000610can properly switch for individual devices whether to use it
611as USB mass storage or not, please tell us how you did it. We
612know we cannot use udev, because udev is called after-the-fact:
613the device is already configured for USB mass storage when
614udev is called.
615
Linus Walleije20abaf2007-12-10 11:20:34 +0000616On Mac OS there is another ugly hack:
617
6181. Open up a terminal window
6192. Type:
620sudo mv /System/Library/Extensions/IOUSBMassStorageClass.kext
621/System/Library/Extensions/IOUSBMassStorageClass.kext.disabled
622
623and when prompted enter your password.
624
6253. Restart.
626
627To reverse this change, just reverse the filenames:
628
629sudo mv /System/Library/Extensions/
630IOUSBMassStorageClass.kext.disabled /System/Library/Extensions/
631IOUSBMassStorageClass.kext
632
633and restart.
634
Linus Walleijbd7624c2007-05-28 10:48:54 +0000635
Linus Walleij15def332006-09-19 14:27:02 +0000636Calendar and contact support:
637-----------------------------
Linus Walleijd3bdf762006-02-20 22:21:56 +0000638
Linus Walleij3c16fe42006-04-30 07:53:41 +0000639The Creative Zen series can read VCALENDAR2 (.ics) files
Linus Walleij15def332006-09-19 14:27:02 +0000640and VCard (.vcf) files from programs like for example
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000641Evolution with the following limitations/conditions:
Linus Walleijd3bdf762006-02-20 22:21:56 +0000642
Linus Walleij3c16fe42006-04-30 07:53:41 +0000643- The file must be in DOS (CR/LF) format, use the unix2dos
644 program to convert if needed
Linus Walleij15def332006-09-19 14:27:02 +0000645
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000646- Repeat events in calendar files do not seem to be supported,
Linus Walleij15def332006-09-19 14:27:02 +0000647 entries will only appear once.
648
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000649- Calendar (.ics) files should be stored in the folder "My Organizer"
Linus Walleij15def332006-09-19 14:27:02 +0000650 when sent to the device (this directory should be autodetected
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000651 for use with calendar files, otherwise use the option
Linus Walleij15def332006-09-19 14:27:02 +0000652 -f "My Organizer" to sendfile for this) Apparently this file can
653 also contain tasklists.
654
655- Contact (.vcf) files should be stored in the folder "My Contacts"
656 when sent to the device. (-f "My Contacts")
657
658- Some devices are picky about the name of the calendar and
659 contact files. For example the Zen Microphoto wants:
660
Linus Walleijb1318d12006-09-25 14:59:26 +0000661 Calendar: My Organizer/6651416.ics
662 Contacts: My Organizer/6651416.vcf
663
664
665Syncing in with Evolution and Creative Devices
666----------------------------------------------
667
668Evolution can easily export .ics an .vcf files, but you currently
669need some command-line hacking to get you stuff copied over in
670one direction host -> device. The examples/ directory contains a script
671created for the Creative Zen Microphoto by Nicolas Tetreault.
672
Linus Walleij6e8cef42006-12-03 20:45:04 +0000673
Linus Walleijd132d8e2007-04-03 23:24:54 +0000674Lost symbols
675------------
676
677Shared libraries can be troublesome to users not experienced with
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000678them. The following is a condensed version of a generic question
Linus Walleijd132d8e2007-04-03 23:24:54 +0000679that has appeared on the libmtp mailing list from time to time.
680
681> PTP: Opening session
682> Queried Creative Zen Vision:M
683> gnomad2: relocation error: gnomad2: undefined symbol:
684> LIBMTP_Get_Storageinfo
685> (...)
686> Are these type of errors related to libmtp or something else?
687
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000688The problem is of a generic nature, and related to dynamic library
Linus Walleijd132d8e2007-04-03 23:24:54 +0000689loading. It is colloquially known as "dependency hell".
690(http://en.wikipedia.org/wiki/Dependency_hell)
691
692The gnomad2 application calls upon the dynamic linker in Linux to
693resolve the symbol "LIBMTP_Get_Storageinfo" or any other symbol
694(ELF symbol, or link point or whatever you want to call them, a
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000695symbol is a label on a memory address that the linker shall
Linus Walleijd132d8e2007-04-03 23:24:54 +0000696resolve from label to actual address.)
697For generic information on this subject see the INSTALL file and
698this Wikipedia page:
699
700http://en.wikipedia.org/wiki/Library_(computing)
701
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000702When Linux /lib/ld-linux.so.X is called to link the symbols compiled
703into gnomad2 (or any other executable using libmtp), it examines the
704ELF file for the libmtp.so.X file it finds first and cannot resolve
Linus Walleijd132d8e2007-04-03 23:24:54 +0000705the symbol "LIBMTP_Get_Storageinfo" (or whichever symbol you have a
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000706problem witj) from it, since it's probably not there. There are many
Linus Walleijd132d8e2007-04-03 23:24:54 +0000707possible causes of this symbol breakage:
708
7091) You installed precompiled libmtp and gnomad2 packages (RPMs, debs
710 whatever) that do not match up. Typical cause: your gnomad2 package was
711 built against a newer version of libmtp than what's installed on your
712 machine. Another typical cause: you installed a package you found on
713 the web, somewhere, the dependency resolution system did not protest
714 properly (as it should) or you forced it to install anyway, ignoring
715 some warnings.
716
7172) You compiled libmtp and/or gnomad2 from source, installing both or
718 either in /usr/local/lib and /usr/local/bin. This means at compile-time
719 gnomad2 finds the libmtp library in /usr/local/lib but at runtime, it
720 depends on the Linux system wide library loader (/lib/ld-linux.so.X) in
721 order to resolve the symbols. This loader will look into the file
722 /etc/ld.so.conf and/or the folder /etc/ld.so.conf.d in order to find
723 paths to libraries to be used for resolving the symbols. If you have
724 some older version of libmtp in e.g. /usr/lib (typically installed by a
725 package manager) it will take precedence over the new version you just
726 installed in /usr/local/lib and the newly compiled library in
727 /usr/local/lib will *not* be used, resulting in this error message.
728
7293) You really did install the very latest versions (as of writing libmtp
730 0.1.5 and gnomad2 2.8.11) from source and there really is no
731 pre-installed package of either on your machine. In that case I'm
732 totally lost, I have no idea what's causing this.
733
734Typical remedies:
735
7361) If you don't want to mess around with your system and risk these
737 situations, only use pre-packaged software that came with the
738 distribution or its official support channels. If it still breaks,
739 blame your distribution, they're not packaging correctly. Relying on
740 properly packaged software and not installing things yourself *is* the
741 Linux solution to the "dependency hell" problem.
742
7432) Read about dynamically linked library handling until the stuff I wrote
744 about in the previous list sounds like music to your ears, inspect
745 your /lib, /usr/lib, /usr/local/lib, /etc/ld.so.conf and the
746 /etc/ld.so.conf.d, remove all pre-packed versions using RPM, APT,
747 YaST or whatever your distribution uses, compile libmtp and gnomad2
748 (or whatever) from source only and you will be enlighted.
749
750I don't know if this helps you, it's the best answer we can give.
Linus Walleij387e37a2008-10-29 17:22:22 +0000751
752
753API is obscure - I want plain files!
754------------------------------------
755
756PTP/MTP devices does not actually contain "files", they contain
757objects. These objects have file names, but that is actually
758just a name tag on the object.
759
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000760Folders/directories aren't really such entities: they are just
Linus Walleij387e37a2008-10-29 17:22:22 +0000761objects too, albeit objects that can act as parent to other
Linus Walleij8aba06d2008-12-28 08:26:57 +0000762objects. They are called "associations" and are created in atomic
Linus Walleij387e37a2008-10-29 17:22:22 +0000763fashion and even though there is an MTP command to get all the
Linus Walleij8aba06d2008-12-28 08:26:57 +0000764associations of a certain association, this command is optional
765so it is perfectly possible (and most common, actually) to create
766devices where the "folders" (which are actually associations) have
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000767no idea whatsoever of what files they are associated as parents to
Linus Walleij387e37a2008-10-29 17:22:22 +0000768(i.e. which files they contain). This is very easy for device
Linus Walleij8aba06d2008-12-28 08:26:57 +0000769manufacturers to implement, all the association (i.e. finding out
770which files are in a certain folder) has to be done by the MTP
771Initiator / host computer.
Linus Walleij387e37a2008-10-29 17:22:22 +0000772
773Moving a file to a new folder is for example very simple in a
774"real" file system. In PTP/MTP devices it is often not even possible,
775some devices *may* be able to do that. But actually the only
776reliable way of doing that is to upload the file to the host,
Linus Walleij8aba06d2008-12-28 08:26:57 +0000777download it with the new parent, then delete the old file.
Linus Walleij387e37a2008-10-29 17:22:22 +0000778We have played with the idea of implementing this time consuming
779function, perhaps we will.
780
Linus Walleij8aba06d2008-12-28 08:26:57 +0000781Then the issue that in PTP/MTP it is legal for two files to have
782exactly the same path as long as their object IDs differ. A
783folder/association can contain two files with the exact same name.
784(And on the Creative devices this even works, too, though most devices
785implicitly fail at this.) Perhaps one could add some custom hook for
786handling that, so they become /Foo.mp3 and /Foo.mp3(1) or something
787similar, but it's really a bit kludgy.
788
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000789Playlists and albums aren't really files, thinking about
Linus Walleij387e37a2008-10-29 17:22:22 +0000790them as files like the hacks in libgphoto2 is really backwards. They are
791called associations and are more like a symbolic link that links in a
792star-shaped pattern to all the files that are part of the album/playlist.
793Some devices (Samsung) thought that was too complicated and have a
794different way of storing playlists in an UTF-16 encoded .spl-like file
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000795instead! This is why playlists/albums must have their own structs and
Linus Walleij387e37a2008-10-29 17:22:22 +0000796functions.
797
Linus Walleij8aba06d2008-12-28 08:26:57 +0000798Plain file access also assumes to be able to write files of an
799undetermined size, which is simply not possible in a transactional
800file system like PTP/MTP. (See further below.)
801
Linus Walleij387e37a2008-10-29 17:22:22 +0000802
803I Want Streaming!
804-----------------
805
806Streaming reads is easy. Just connect the output file descriptor from
807LIBMTP_Get_File_To_File_Descriptor() (and a similar function for tracks)
808wherever you want.
809
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000810People have connected this to TCP sockets for streaming web servers
811etc, works like a charm. Some devices will even survive if the callback
Linus Walleij387e37a2008-10-29 17:22:22 +0000812functions return non-zero and cancel the download. Some devices will
813lock up and even require a reset if you do that. Devices are poorly
814implemented so that's life. If you want to stream off a device, the
815best idea is always to stream the entire file and discard the stuff
816at the end you don't want. It will incur a delay if you e.g. want to
817skip between tracks, sadly.
818
819Then we get to the complicated things: streaming WRITES...
820
821There is a function:
822LIBMTP_Send_File_From_File_Descriptor() (and similar for tracks)
823which will write a file to a device from a file descriptor, which may
824be a socket or whatever.
825
826HOWEVER: this requires a piece of metadata with the .filesize properly
827set first.
828
829This is not because we think it is funny to require that, the protocol
830requires it. The reason is that PTP/MTP is a transactional file system
831and it wants to be able to deny file transfer if the file won't fit on
832the device, so the transaction never even starts, it's impossible to
833start a transaction without giving file length.
834
835People really want streaming so I tried a lot of hacks to see if they
836would work, such as setting file size to 0xffffffffU or something other
837unnaturally big and then aborting the file transfer when the stream ends.
838It doesn't work: either the device crashes or the file simply disappears
839since the device rolls back all failed transactions.
840
841So this is an inherent limitation of the PTP/MTP protocol.
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000842
843
Linus Walleijae890212012-02-16 01:56:19 +0100844I want to remote control my device!
845-----------------------------------
846
847I have both good and bad news for you.
848
849The good news is that the MTP protocol has well-defined commands to play
850back content on a device. Operation 0xD411 (PTP_DPC_MTP_PlaybackObject)
851will start playing back a file on the device (whatever that may mean if
852this is not a music or video file), and operation 0xD403 can set the
853playback volume to save your ears. Then there are operations to
854determine how far into the current file you currently are, so as to
855support say progress bars.
856
857Since these commands have been around since the dawn of the MTP protocol
858and since it was developed in cooperation with Creative Technology, this
859is probably a requested feature from the Creative people who already had
860support for playback on their devices using the PDE protocol back then.
861
862Anyway, here are the bad news:
863[logs]$ grep d411 *
864mtp-detect-trekstor-vibez.txt: 0xd411: Playback Object
865
866Aha there is only one known device in the world which actually supports
867playback on the device. So either you go buy the Trekstor Vibez, or you
868can forget about this. You could always try asking your hardware vendor
869of choice to go implement this.
870
871Since none of the core developers of libmtp has the Trekstor device, this
872is not yet implemented in libmtp.
873
874
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000875I make MTP devices!
876-------------------
877
878If you are a device vendor there is a lot you can do for libmtp:
879
880* Please consider assigning one of your employees as a contact person
881 for libmtp, have them sign up to the libmtp development list and answer
882 questions and post new device ID:s as they are released to our
883 mailing list.
884
885* If you want to help even more, assign someone to look deeper into
886 error reports on your specific devices, understand why your firmware
887 may require some special device flags and what can be done about it.
888
889* Do you have spare devices you can give us? Send them to Richard (Mac
890 support) or Linus (Linux support). (So far nobody did that except for
891 Microsoft who sent us a Zune by proxy!)
892
893Vendors do need help from libmtp too, especially we want to help
894vendors improve their MTP stacks, because they all suffer from the
895same problem: the lack of a proper conformance test has made many devices
896incompliant with the MTP specification as it is published today: most
897devices are just compliant with the Windows MTP stack, and don't work
898out-of-the-box with libmtp. We need someone on the inside to help in
899bug reporting vendors MTP stacks internally so these issues are raised.
900A good way to go toward better MTP compliance is to test with an
901alternative implementation of the stack. In e.g. IETF standardization
902it is compulsory for an RFC to have atleast two independent implementations
903for it to reach the status as standard.
904
905Being compliant with libmtp is also more and more important for
906vendors: libmtp is being deployed in some embedded systems like
907set-top-boxes etc. It will be very irritating for customers if a device
908will not dock properly with some home entertainment equipment just because
909it is based on Linux and libmtp and not the Windows MTP stack.
Linus Walleij5f5c69f2011-06-26 14:34:13 +0200910
911Autodetect with gudev
912---------------------
913
914Previously you would use HAL to detect devices being plugged in. Nowadays
915we use udev directly, or though the GNOME libgudev library. LIBMTPs
916default udev rules export the proper properties to detect any MTP device
917automatically, here is a verbose example derived from gnomad2:
918
919#define G_UDEV_API_IS_SUBJECT_TO_CHANGE
920#include <gudev/gudev.h>
921const char * const gudev_subsystems[] = { "usb", NULL };
922GUdevClient *gudev_client;
923guint uevent_id;
924guint uevent_bus_hooked = 0;
925guint uevent_device_hooked = 0;
926
927
928static void uevent_cb(GUdevClient *client, const char *action, GUdevDevice *device, void *data)
929{
930 guint64 devicenum;
931 guint vendor;
932 guint model;
933 guint busnum;
934 guint devnum;
935 guint mtpdevice;
936
937 devicenum = (guint64) g_udev_device_get_device_number(device);
938 g_print("%s event for %s (%"G_GINT64_MODIFIER"x)", action,
939 g_udev_device_get_sysfs_path (device), devicenum);
940
941 /* get device info */
942 vendor = get_property_as_int(device, "ID_VENDOR_ID", 16);
943 model = get_property_as_int(device, "ID_MODEL_ID", 16);
944 busnum = get_property_as_int(device, "BUSNUM", 10);
945 devnum = get_property_as_int(device, "DEVNUM", 10);
946 mtpdevice = get_property_as_int(device, "ID_MTP_DEVICE", 10);
947
948 if (vendor == 0 || model == 0) {
949 g_print("couldn't get vendor or model ID for device at (%x:%x)\n",
950 busnum, devnum);
951 return;
952 } else {
953 g_print("vendor = %x, model = %x, bus = %x, device = %x\n",
954 vendor, model, busnum, devnum);
955 }
956
957 if (mtpdevice) {
958 g_print("device is MTP compliant\n");
959
960 if (g_str_equal(action, "add") &&
961 uevent_bus_hooked == 0 &&
962 uevent_device_hooked == 0) {
963 g_print(MTP device plugged in!\n");
964 uevent_bus_hooked = busnum;
965 uevent_device_hooked = devnum;
966 scan_jukebox(NULL);
967 } else if (g_str_equal (action, "remove") &&
968 uevent_bus_hooked == busnum &&
969 uevent_device_hooked == devnum) {
970 g_print("MTP device removed!\n");
971 uevent_bus_hooked = 0;
972 uevent_device_hooked = 0;
973 }
974 }
975}
976
977
978
979(...)
980 /*
981 * Monitor udev device events - we're only really interested in events
982 * for USB devices.
983 */
984 gudev_client = g_udev_client_new(gudev_subsystems);
985 uevent_id = g_signal_connect_object(gudev_client,
986 "uevent",
987 G_CALLBACK(uevent_cb),
988 NULL, 0);
Linus Walleij187ac2f2012-05-02 19:08:03 +0200989
990SKETCH OF AN OVERVIEW
991---------------------
992
993Draft agenda for a talk on MTP devices submitted for the Android
994builders summit, might come to recycle this:
995
996- Protocol overview
997- libmtp interface
998- relation to libgphoto2
999- Device sins
1000 - Android bugs
1001 - Samsungs special Android MTP stack
1002 - SonyEricsson Aricent stack for Xperia Androids pre 4.0, broken headers!
1003- Detecting from vendor extension, can fix in newer extensions!
1004- Autoprobing on Linux
1005 - Color devices do not like autoprobing
1006- Ideas??
1007- Mode switch devices?
1008- MTPZ