blob: 7003f4f9eddb2b8790d519fab1c34e640670a9cf [file] [log] [blame]
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
153* Generic MTP/PTP disconnect misbehaviour: we have noticed that
154 Windows Media Player apparently never close the session to an MTP
155 device. There is a daemon in Windows that "hooks" the device
156 by opening a PTP session to any MTP device, whenever it is
157 plugged in. This daemon proxies any subsequent transactions
158 to/from the device and will never close the session, thus
159 Windows simply does not close sessions at all.
160
Linus Walleije962add2012-01-13 20:22:22 +0100161 For example this means that a device may work the first time
162 you run some command-line example like "mtp-detect" while
163 subsequent runs fail.
164
Linus Walleijc36e2a62011-12-29 21:31:49 +0100165 Typical sign of this illness: broken pipes on closing sessions,
166 on the main transfer pipes(s) or the interrupt pipe:
167
168 Closing session
169 usb_clear_halt() on INTERRUPT endpoint: Broken pipe
170 OK.
171
172 This means that device manufacturers doesn't notice any problems
173 with devices that do not correctly handle closing PTP/MTP
174 sessions, since Windows never do it. The proper way of closing
175 a session in Windows is to unplug the device, simply put.
176
177 Since libmtp actually tries to close sessions, some devices
178 may fail since the close session functionality has never been
179 properly tested, and "it works with Windows" is sort of the
180 testing criteria at some companies.
181
Linus Walleije962add2012-01-13 20:22:22 +0100182 You can get Windows-like behaviour on Linux by running a udev-aware
Linus Walleijc36e2a62011-12-29 21:31:49 +0100183 libmtp GUI client like Rhythmbox or Gnomad2, which will "hook"
184 the device when you plug it in, and "release" it if you unplug
Linus Walleije962add2012-01-13 20:22:22 +0100185 it, and you start/end you transfer sessions by plugging/unplugging
186 the USB cable.
187
188 The "Unix way" of running small programs that open the device,
189 do something, then close the device, isn't really working with
190 such devices and you cannot expect to have command line tools
191 like the mtp examples work with them. You could implement new
192 example programs that just call to a mediating daemon like the
193 Windows MTP stack does. (And change all programs using libmtp
194 directly today.)
Linus Walleijc36e2a62011-12-29 21:31:49 +0100195
196 If this bug in your device annoys you, contact your device
197 manufacturer and ask them to test their product with some libmtp
198 program.
199
Linus Walleijf776f7b2012-06-06 10:14:05 +0200200* Samsung Android 2.3.x devices: these have a special MTP stack
201 with some specific bugs that we have maybe nailed down now.
202 It suffers from an "immediate connect" syndrome, i.e. you have
203 to connect to the device within 7 seconds of plugging in, or it
204 will go numb. This also goes for command-line activity with
205 the example programs, so this device is better used with a
206 GUI tool like Rhythmbox, gnomad2...
207
Linus Walleijc36e2a62011-12-29 21:31:49 +0100208* Generic USB misbehaviour: some devices behave badly under MTP
209 and USB mass storage alike, even down to the lowest layers
210 of USB. You can always discuss such issues at the linux-usb
211 mailing list if you're using Linux:
212 http://www.linux-usb.org/mailing.html
213
214 If you have a problem specific to USB mass storage mode, there
215 is a list of strange behaving devices in the Linux kernel:
216 http://lxr.linux.no/linux/drivers/usb/storage/unusual_devs.h
217 You can discuss this too on the mentioned list, for understanding
218 the quirks, see:
219 http://www2.one-eyed-alien.net/~mdharm/linux-usb/target_offenses.txt
220
221* Generic certificate misbehaviour. All devices are actually
222 required to support a device certificate to be able to
223 encrypt Windows Media (WMA/WMV) files. However there are
224 obviously a lot of devices out there which doesn't support
225 this at all but instead crash. Typical printout:
226
227 Error 2: PTP Layer error 02ff: get_device_unicode_property(): failed
228 to get unicode property.
229
230 This should only affect "mtp-detect", there is no other
231 application currently retrieveing the certificate (not that we
232 know anyway).
233
234* Kernel bug on Linux. Linux 2.6.16 is generally speaking required
235 to use any MTP device under USB 2.0. This is because the EHCI
236 driver previously did not support zero-length writes to endpoints.
237 It should work in most cases however, or if you connect it
238 to an UHCI/OHCI port instead (yielding lower speed). But
239 please just use a recent kernel.
240
241* Zen models AVI file seeking problem: the Zens cannot parse the
242 files for the runlength metadata. Do not transfer file with e.g.
243 mtp-sendfile, use mtp-sendtr and set the length of the track to
244 the apropriate number of seconds and it will work. In graphical
245 clients, use a "track transfer" function to send these AVI files,
246 the Zens need the metadata associated with tracks to play back
247 movies properly. Movies are considered "tracks" in the MTP world.
248
249* Some devices that disregard the metadata sent with the MTP
250 commands will parse the files for e.g. ID3 metadata. Some still
251 of these devices expect only ID3v2.3 metadata and will fail with
252 a modern ID3v2,4 tag writer, like many of those found in Linux
253 applications. Windows Media Player use ID3v2.3 only, so many
254 manufacturers only test this version.
255
256* The Zen Vision:M (possibly more Creative Zens) has a firmware bug
257 that makes it drop the last two characters off a playlist name.
258 It is fixed in later firmware.
259
260* For Creative Technology devices, there are hard limits on how
261 many files can be put onto the device. For a 30 GiB device (like
262 the Zen Xtra) the limit is 6000, for a 60 GiB device the limit
263 is 15000 files. For further Creative pecularities, see the
264 FAQ sections at www.nomadness.net.
265
266* Sandisk sansa c150 and probably several other Sandisk devices
267 (and possibly devices from other manufacturers) have a dual
268 mode with MTP and USB mass storage. The device will initially
269 claim to be mass storage so udev will capture is and make the
270 use of MTP mode impossible. One way of avoiding it could be to
271 be to blacklist the "usb-storage" module in
272 /etc/modprobe.c/blacklist with a row like this:
273 "blacklist usb-storage". Some have even removed the
274 "usb-storage.ko" (kernel module file) to avoid loading.
275
276* Sandisk Sansa Fuze has three modes: auto, MTP or mass storage
277 (MSC). Please set it to MTP to avoid problems with libmtp.
278
279* The iriver devices (possibly all of them) cannot handle the
280 enhanced GetObjectPropList MTP command (0x9805) properly. So
281 they have been banned from using it.
282
283* iriver devices have problems with older versions of libmtp and
284 with new devices libmtp does not know of as of yet, since it
285 has an oldstyle USB device controller that cannot handle zero
286 writes. (Register your device with us!) All their devices are
287 likely to need a special device flag in the src/libusb-glue.c
288 database.
289
290* The Samsung Yepp T9 has several strange characteristics, some
291 that we've managed to work around. (For example it will return
292 multiple PTP packages in a single transaction.)
293
294* The early firmware for Philips HDD players is known to be
295 problematic. Please upgrade to as new firmware as you can get.
296 (Yes this requires some kind of Windows Installation I think.)
297
298* Philips HDD 1630/16 or 1630/17 etc may lock themselves up,
299 turning inresponsive due to internal corruption. This typically
300 gives an error in opening the PTP session. Apparently you can
301 do a "repair" with the firmware utility (Windows only) which
302 will often fix this problem and make the device responsive
303 again.
304
305* Some devices that implement GetObjectPropList (0x9805) will
306 not return the entire object list if you request a list for object
307 0xffffffffu. (But they should.) So they may need the special
308 DEVICE_FLAG_BROKEN_MTPGETOBJPROPLIST_ALL.
309
310* Some (smaller) subset of devices cannot even get all the
311 properties for a single object in one go, these need the
312 DEVICE_FLAG_BROKEN_MTPGETOBJPROPLIST. Currently only the
313 iriver devices seem to have this bug.
314
315* The Toshiba Gigabeat S (and probably its sibling the
316 Microsoft Zune and other Toshiba devices) will only display
317 album information tags for a song in case there is also
318 an abstract album (created with the album interface) with
319 the exact same name.
320
321* The Zen Vision:M has an older firmware which is very corrupt,
322 it is incompatible with the Linux USB stack altogether. The
323 kernel dmesg will look something like this, and you have to
324 upgrade the firmware using Windows:
325 usb 4-5: new high speed USB device using ehci_hcd and address 5
326 usb 4-5: configuration #1 chosen from 1 choice
327 usb 4-5: can't set config #1, error -110
328
329* The Sirus Stiletto does not seem to allow you to copy any files
330 off the device. This may be someone's idea of copy protection.
331
332* The Samsung P2 assigns parent folder ID 0 to all unknown file
333 types.(i.e. moves them to the root folder)
334
335* The Sandisk Sansa Clip+ needs a firmware upgrade in earlier
336 versions in order to work properly.
337
338
Linus Walleija1b66f22007-05-10 20:02:16 +0000339New Devices
340-----------
341
Linus Walleijfcf88912006-06-05 13:23:33 +0000342If you happen upon a device which libmtp claims it cannot
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000343autodetect, please submit the vendor ID and device ID
Linus Walleij9ee29402007-10-31 20:24:48 +0000344(these can be obtained from the "lsusb" and "lsusb -n"
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000345commands run as root) as a bug, patch or feature request
346on the Sourceforge bug tracker at our homepage. If it
347gives a sensible output from "mtp-detect" then please attach
348the result as well as it teach us some stuff about your
349device. If you've done some additional hacking, join our
Linus Walleij9ee29402007-10-31 20:24:48 +0000350mailinglist and post your experiences there.
Linus Walleijda558be2007-03-10 21:42:25 +0000351
Linus Walleija1b66f22007-05-10 20:02:16 +0000352If you want to be able to hack some more and you're not
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000353afraid of C hacking, add an entry for your device's
354vendor/product ID and a descriptive string to the database
Linus Walleij6dc01682007-11-15 21:23:46 +0000355in the file src/music-players.h.
Linus Walleija1b66f22007-05-10 20:02:16 +0000356
357If you want to poke around to see if your device has some
358special pecularities, you can test some special device
Linus Walleij6dc01682007-11-15 21:23:46 +0000359flags (defined in src/device-flags.h) by inserting them
360together with your device entry in src/music-players.h.
Linus Walleija1b66f22007-05-10 20:02:16 +0000361Flags can be tested in isolation or catenated with "|"
362(binary OR). If relatives to your device use a certain
363flag, chances are high that a new device will need it
364too, typically from the same manufacturer.
365
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000366The most common flag that needs to be set is the
Linus Walleija1b66f22007-05-10 20:02:16 +0000367DEVICE_FLAG_UNLOAD_DRIVER that detach any Linux kernel
368drivers that may have attached to the device making
Linus Walleij94f23d52007-08-04 19:37:28 +0000369MTP access impossible. This is however not expected to
370really work: this is a problem being tracked as of
371now (2007-08-04). See the "last resort" solutions below
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000372if you really need to get your dual-mode device to work
Linus Walleij94f23d52007-08-04 19:37:28 +0000373with MTP.
Linus Walleija1b66f22007-05-10 20:02:16 +0000374
Linus Walleijcc2cf972007-11-22 20:23:43 +0000375Another flag which is easy to identify is the
376DEVICE_FLAG_NO_ZERO_READS, which remedies connection
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000377timeouts when getting files, and some timeouts on e.g.
Linus Walleijcc2cf972007-11-22 20:23:43 +0000378successive "mtp-connect" calls.
379
Linus Walleija1b66f22007-05-10 20:02:16 +0000380If your device is very problematic we are curious of how it
Linus Walleijda558be2007-03-10 21:42:25 +0000381works under Windows, so we enjoy reading USB packet sniffs
382that reveal the low-level traffic carried out between
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000383Windows Media Player and your device. This can be done
Linus Walleij61c25682007-09-04 14:46:21 +0000384using e.g.:
385
386* USBsnoop:
387 http://benoit.papillault.free.fr/usbsnoop/
388
389* The trial version of HHD Softwares software-only
390 USB monitor. You need to get a copy of version 2.37 since
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000391 the newer trial versions won't let you carry out the
Linus Walleij61c25682007-09-04 14:46:21 +0000392 needed packet sniffs. (As of 2007-03-10 a copy can be found
393 at: http://www.cobbleware.com/files/usb-monitor-237.exe)
394
Linus Walleijda558be2007-03-10 21:42:25 +0000395There are other USB monitors as well, some more expensive
396alternatives use hardware and even measure electronic
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000397characteristics of the traffic (which is far too much
Linus Walleijda558be2007-03-10 21:42:25 +0000398detail for us).
399
Linus Walleij91fb0282007-09-03 21:16:08 +0000400Device sniffs are an easy read since the PTP/MTP protocol
401is nicely structured. All commands will have a structure such
402as this in the log, we examplify with a object list request:
403
404PTP REQEUST:
405000120: Bulk or Interrupt Transfer (UP), 03.09.2007 12:49:25.9843750 +0.0
406Pipe Handle: 0x863ce234 (Endpoint Address: 0x2)
407Send 0x20 bytes to the device:
408 20 00 00 00 01 00 05 98 23 00 00 00 27 03 00 10 ......?#...'...
409 Length TYPE CMD Trans# Param1
410
411 00 00 00 00 02 DC 00 00 00 00 00 00 00 00 00 00 .....Ü..........
412 Param2 Param3 Param4 Param5
413
414[OPTIONAL] DATA PHASE:
415000121: Bulk or Interrupt Transfer (UP), 03.09.2007 12:49:26.0 +0.0156250
416Pipe Handle: 0x863ce214 (Endpoint Address: 0x81)
417Get 0x1a bytes from the device:
418 1A 00 00 00 02 00 05 98 23 00 00 00 01 00 00 00 .......?#.......
419 Length TYPE CMD Trans# DATA
420
421 27 03 00 10 02 DC 04 00 00 30 '....Ü...0
422
423RESPONSE:
424000122: Bulk or Interrupt Transfer (UP), 03.09.2007 12:49:26.0 +0.0
425Pipe Handle: 0x863ce214 (Endpoint Address: 0x81)
426Get 0xc bytes from the device:
427 0C 00 00 00 03 00 01 20 23 00 00 00 ....... #...
428 Length TYPE CODE Trans#
429
430* One send (OUT to the device), two reads (IN from the device).
431
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000432* All three byte chunks commands are
433 sent/recieved/recieeved by the function ptp_transaction()
Linus Walleij91fb0282007-09-03 21:16:08 +0000434 in the file ptp.c.
435
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000436* It boils down to ptp_usb_sendreq(), optionally ptp_usb_senddata()
437 or ptp_usb_getdata() and finally ptp_usb_getresp() in the file
Linus Walleij91fb0282007-09-03 21:16:08 +0000438 libusb-glue.c. Notice ptp_usb_sendreq() and ptp_usb_getresp()
439 are ALWAYS called. The TYPE field correspond to this, so the
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000440 TYPES in this case are "COMMAND" (0x0001), "DATA" (0x0002),
Linus Walleij91fb0282007-09-03 21:16:08 +0000441 and "RESPONSE" (0x0003).
442
443* Notice that the byte order is little endian, so you need to read
444 each field from right to left.
445
446* This COMMAND has:
447 CMD 0x99805, we see in ptp.h that this is PTP_OC_MTP_GetObjPropList.
448 Transaction# 0x00000023.
449 REQUEST parameters 0x10000327, 0x00000000, 0x0000DC02, 0x00000000
450 0x00000000, in this case it means "get props for object 0x10000327",
451 "any format", "property 0xDC02" (PTP_OPC_ObjectFormat), then two
452 parameters that are always zero (no idea what they mean or their
453 use).
454
455* The DATA has:
456 CMD 0x99805, we see in ptp.h that this is PTP_OC_MTP_GetObjPropList.
457 Transaction# 0x00000023.
458 Then comes data 0x00000001, 0x10000327, 0xDC02, 0x0004, 0x3000
459 Which means in this case, (and this is the tricky part) "here
460 you have 1 property", "for object 0x10000327", "it is property
461 0xDC02" (PTP_OPC_ObjectFormat), "which is of type 0x0004"
462 (PTP_DTC_UINT16), "and set to 0x3000" (PTP_OFC_Undefined, it
463 is perfectly valid to have undefined object formats, since it
464 is a legal value defining this).
465
466* This RESPONSE has:
467 CMD 0x99805, we see in ptp.h that this is PTP_OC_MTP_GetObjPropList.
468 Return Code ("RC") = 0x2001, PTP_RC_OK, all went fine.
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000469 Transaction# 0x00000023.
Linus Walleijfcf88912006-06-05 13:23:33 +0000470
Linus Walleijd05fce62007-09-29 20:17:23 +0000471If you want to compare the Windows behaviour with a similar
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000472operation using libmtp you can go into the src/libusb-glue.c
Linus Walleij6dc01682007-11-15 21:23:46 +0000473file and uncomment the row that reads:
Linus Walleijd05fce62007-09-29 20:17:23 +0000474
475//#define ENABLE_USB_BULK_DEBUG
476
477(I.e. remove the two //.)
478
479This will make libmtp print out a hex dump of every bulk USB
480transaction. The bulk transactions contain all the PTP/MTP layer
481data, which is usually where the problems appear.
482
Linus Walleij6fd2f082006-03-28 07:19:22 +0000483
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200484Notes to assist with debugging new devices:
485-------------------------------------------
486
Linus Walleijc36e2a62011-12-29 21:31:49 +0100487In debugging new hardware, we highly recommend that you only
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200488use the example mtp-* applications that come with libmtp, as other
489applications may have their own bugs that may interfere with your
490new device working correctly. Using another application instead of
491those that come with libmtp just adds another point of failure.
492
493For debugging, there are 3 main options:
494
Linus Walleijc36e2a62011-12-29 21:31:49 +01004951. Use the env variable: LIBMTP_DEBUG to increase the
496verboseness of the debugging output for any application using
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200497libmtp. Relevant codes are:
498* 0x00 [0000 0000] : no debug (default)
499* 0x01 [0000 0001] : PTP debug
500* 0x02 [0000 0010] : Playlist debug
501* 0x04 [0000 0100] : USB debug
502* 0x08 [0000 1000] : USB data debug
503// Codes are hex and binary respectively. Simple add them togther
504// to get your desired level of output.
505
506(Assuming bash)
Linus Walleijc36e2a62011-12-29 21:31:49 +0100507eg:
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200508$ export LIBMTP_DEBUG=12
509$ mtp-detect
510 // To get USB debug and USB data debug information.
511
512$ export LIBMTP_DEBUG=2
513$ mtp-detect
514 // To get Playlist debug information.
Linus Walleijc36e2a62011-12-29 21:31:49 +0100515
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200516Also note, an application may also use the LIBMTP_debug() API
517function to achieve the same options as listed above.
518
Linus Walleijc36e2a62011-12-29 21:31:49 +01005192. Use "strace" on the various mtp-* commands to see where/what
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200520is falling over or getting stuck at.
521* On Solaris and FreeBSD, use "truss" or "dtrace" instead on "strace".
522* On Mac OS X, use "ktrace" or "dtrace" instead of "strace".
523* On OpenBSD and NetBSD, use "ktrace" instead of "strace".
524
525This will at least help pinpoint where the application is failing, or
Linus Walleijc36e2a62011-12-29 21:31:49 +0100526a device is reporting incorrect information. (This is extremely helpful
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200527with devices that have odd disconnection requirements).
528
Linus Walleijc36e2a62011-12-29 21:31:49 +0100529The use of these tools may also pinpoint issues with libusb as
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200530implemented by each OS vendor or issues with the MTP implementation
531on the new device as well, so please be prepared for either case.
532
5333. Use "gdb" or similar debugger to step through the code as it is
534run. This is time consuming, and not needed just to pinpoint where
Linus Walleijc36e2a62011-12-29 21:31:49 +0100535the fault is.
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200536
Linus Walleijc36e2a62011-12-29 21:31:49 +0100537The use of gdb or another debugger may also miss or actually cause
538command and data timing issues with some devices, leading to false
Darran Kartaschewa476ae92011-08-08 09:07:30 +0200539information. So please consider this a last resort option.
540
541Also please read the "It's Not Our Bug!" section below, as it does
542contain some useful information that may assist with your device.
543
544
Linus Walleij8d799eb2009-07-23 22:58:06 +0000545Dual-mode devices does not work - last resort:
546----------------------------------------------
Linus Walleijbd7624c2007-05-28 10:48:54 +0000547
548Some devices that are dual-mode are simply impossible to get
549to work under Linux because the usb-storage(.ko) kernel
550module hook them first, and refuse to release them, even
Linus Walleij94f23d52007-08-04 19:37:28 +0000551when we specify the DEVICE_FLAG_UNLOAD_DRIVER flag. (Maybe
552it DOES release it but the device will immediately be probed
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000553at the USB mass storage interface AGAIN because it
Linus Walleij94f23d52007-08-04 19:37:28 +0000554enumerates.)
Linus Walleijbd7624c2007-05-28 10:48:54 +0000555
Linus Walleij8d799eb2009-07-23 22:58:06 +0000556Here is what some people do:
557
558 1. Plug in the device.
559 2. USB-mass storage folder will open automatically.
560 3. Unmount the device.
561 4. Run mtp-detect. It will most likely fail the first time.
562 5. Run mtp-detect again, it might work this time, or fail. Keep running
563 till it works. 99% it works by the third try.
564 6. Once mtp-detect gives you an "Ok", open either Rhythmbox or Gnomad2,
565 everything should work.
566
Linus Walleije20abaf2007-12-10 11:20:34 +0000567Linux: Try this, if you have a recent 2.6.x Linux kernel,
Linus Walleij584eb8d2007-09-05 19:51:27 +0000568run (as root) something like:
569
570> rmmod usb_storage ; mtp-detect
571
572You can run most any command or a client like gnomad2 or
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000573Amarok immediately after the rmmod command. This works
Linus Walleij584eb8d2007-09-05 19:51:27 +0000574sometimes. Another way:
Linus Walleijbd7624c2007-05-28 10:48:54 +0000575
Linus Walleij94f23d52007-08-04 19:37:28 +0000576* Edit /etc/modprobe.d/blacklist
Linus Walleijbd7624c2007-05-28 10:48:54 +0000577
578* Add the line "blacklist usb-storage"
579
580* Reboot.
581
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000582Now none of you USB disks, flash memory sticks etc will be
Linus Walleijbd7624c2007-05-28 10:48:54 +0000583working (you just disabled them all). However you *can* try
584your device, and it might have started working because there
585is no longer a USB mass storage driver that tries to hook onto
586the mass storage interface of your device.
587
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000588If not even blacklisting works (check with
Linus Walleij94f23d52007-08-04 19:37:28 +0000589"lsmod | grep usb-storage"), there is some problem with
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000590something else and you may need to remove or rename the file
Linus Walleij94f23d52007-08-04 19:37:28 +0000591/lib/modules/<VERSION>/kernel/drivers/usb/storage/usb-storage.ko
592manually.
593
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000594If you find the PerfectSolution(TM) to this dilemma, so you
Linus Walleijbd7624c2007-05-28 10:48:54 +0000595can properly switch for individual devices whether to use it
596as USB mass storage or not, please tell us how you did it. We
597know we cannot use udev, because udev is called after-the-fact:
598the device is already configured for USB mass storage when
599udev is called.
600
Linus Walleije20abaf2007-12-10 11:20:34 +0000601On Mac OS there is another ugly hack:
602
6031. Open up a terminal window
6042. Type:
605sudo mv /System/Library/Extensions/IOUSBMassStorageClass.kext
606/System/Library/Extensions/IOUSBMassStorageClass.kext.disabled
607
608and when prompted enter your password.
609
6103. Restart.
611
612To reverse this change, just reverse the filenames:
613
614sudo mv /System/Library/Extensions/
615IOUSBMassStorageClass.kext.disabled /System/Library/Extensions/
616IOUSBMassStorageClass.kext
617
618and restart.
619
Linus Walleijbd7624c2007-05-28 10:48:54 +0000620
Linus Walleij15def332006-09-19 14:27:02 +0000621Calendar and contact support:
622-----------------------------
Linus Walleijd3bdf762006-02-20 22:21:56 +0000623
Linus Walleij3c16fe42006-04-30 07:53:41 +0000624The Creative Zen series can read VCALENDAR2 (.ics) files
Linus Walleij15def332006-09-19 14:27:02 +0000625and VCard (.vcf) files from programs like for example
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000626Evolution with the following limitations/conditions:
Linus Walleijd3bdf762006-02-20 22:21:56 +0000627
Linus Walleij3c16fe42006-04-30 07:53:41 +0000628- The file must be in DOS (CR/LF) format, use the unix2dos
629 program to convert if needed
Linus Walleij15def332006-09-19 14:27:02 +0000630
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000631- Repeat events in calendar files do not seem to be supported,
Linus Walleij15def332006-09-19 14:27:02 +0000632 entries will only appear once.
633
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000634- Calendar (.ics) files should be stored in the folder "My Organizer"
Linus Walleij15def332006-09-19 14:27:02 +0000635 when sent to the device (this directory should be autodetected
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000636 for use with calendar files, otherwise use the option
Linus Walleij15def332006-09-19 14:27:02 +0000637 -f "My Organizer" to sendfile for this) Apparently this file can
638 also contain tasklists.
639
640- Contact (.vcf) files should be stored in the folder "My Contacts"
641 when sent to the device. (-f "My Contacts")
642
643- Some devices are picky about the name of the calendar and
644 contact files. For example the Zen Microphoto wants:
645
Linus Walleijb1318d12006-09-25 14:59:26 +0000646 Calendar: My Organizer/6651416.ics
647 Contacts: My Organizer/6651416.vcf
648
649
650Syncing in with Evolution and Creative Devices
651----------------------------------------------
652
653Evolution can easily export .ics an .vcf files, but you currently
654need some command-line hacking to get you stuff copied over in
655one direction host -> device. The examples/ directory contains a script
656created for the Creative Zen Microphoto by Nicolas Tetreault.
657
Linus Walleij6e8cef42006-12-03 20:45:04 +0000658
Linus Walleijd132d8e2007-04-03 23:24:54 +0000659Lost symbols
660------------
661
662Shared libraries can be troublesome to users not experienced with
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000663them. The following is a condensed version of a generic question
Linus Walleijd132d8e2007-04-03 23:24:54 +0000664that has appeared on the libmtp mailing list from time to time.
665
666> PTP: Opening session
667> Queried Creative Zen Vision:M
668> gnomad2: relocation error: gnomad2: undefined symbol:
669> LIBMTP_Get_Storageinfo
670> (...)
671> Are these type of errors related to libmtp or something else?
672
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000673The problem is of a generic nature, and related to dynamic library
Linus Walleijd132d8e2007-04-03 23:24:54 +0000674loading. It is colloquially known as "dependency hell".
675(http://en.wikipedia.org/wiki/Dependency_hell)
676
677The gnomad2 application calls upon the dynamic linker in Linux to
678resolve the symbol "LIBMTP_Get_Storageinfo" or any other symbol
679(ELF symbol, or link point or whatever you want to call them, a
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000680symbol is a label on a memory address that the linker shall
Linus Walleijd132d8e2007-04-03 23:24:54 +0000681resolve from label to actual address.)
682For generic information on this subject see the INSTALL file and
683this Wikipedia page:
684
685http://en.wikipedia.org/wiki/Library_(computing)
686
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000687When Linux /lib/ld-linux.so.X is called to link the symbols compiled
688into gnomad2 (or any other executable using libmtp), it examines the
689ELF file for the libmtp.so.X file it finds first and cannot resolve
Linus Walleijd132d8e2007-04-03 23:24:54 +0000690the symbol "LIBMTP_Get_Storageinfo" (or whichever symbol you have a
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000691problem witj) from it, since it's probably not there. There are many
Linus Walleijd132d8e2007-04-03 23:24:54 +0000692possible causes of this symbol breakage:
693
6941) You installed precompiled libmtp and gnomad2 packages (RPMs, debs
695 whatever) that do not match up. Typical cause: your gnomad2 package was
696 built against a newer version of libmtp than what's installed on your
697 machine. Another typical cause: you installed a package you found on
698 the web, somewhere, the dependency resolution system did not protest
699 properly (as it should) or you forced it to install anyway, ignoring
700 some warnings.
701
7022) You compiled libmtp and/or gnomad2 from source, installing both or
703 either in /usr/local/lib and /usr/local/bin. This means at compile-time
704 gnomad2 finds the libmtp library in /usr/local/lib but at runtime, it
705 depends on the Linux system wide library loader (/lib/ld-linux.so.X) in
706 order to resolve the symbols. This loader will look into the file
707 /etc/ld.so.conf and/or the folder /etc/ld.so.conf.d in order to find
708 paths to libraries to be used for resolving the symbols. If you have
709 some older version of libmtp in e.g. /usr/lib (typically installed by a
710 package manager) it will take precedence over the new version you just
711 installed in /usr/local/lib and the newly compiled library in
712 /usr/local/lib will *not* be used, resulting in this error message.
713
7143) You really did install the very latest versions (as of writing libmtp
715 0.1.5 and gnomad2 2.8.11) from source and there really is no
716 pre-installed package of either on your machine. In that case I'm
717 totally lost, I have no idea what's causing this.
718
719Typical remedies:
720
7211) If you don't want to mess around with your system and risk these
722 situations, only use pre-packaged software that came with the
723 distribution or its official support channels. If it still breaks,
724 blame your distribution, they're not packaging correctly. Relying on
725 properly packaged software and not installing things yourself *is* the
726 Linux solution to the "dependency hell" problem.
727
7282) Read about dynamically linked library handling until the stuff I wrote
729 about in the previous list sounds like music to your ears, inspect
730 your /lib, /usr/lib, /usr/local/lib, /etc/ld.so.conf and the
731 /etc/ld.so.conf.d, remove all pre-packed versions using RPM, APT,
732 YaST or whatever your distribution uses, compile libmtp and gnomad2
733 (or whatever) from source only and you will be enlighted.
734
735I don't know if this helps you, it's the best answer we can give.
Linus Walleij387e37a2008-10-29 17:22:22 +0000736
737
738API is obscure - I want plain files!
739------------------------------------
740
741PTP/MTP devices does not actually contain "files", they contain
742objects. These objects have file names, but that is actually
743just a name tag on the object.
744
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000745Folders/directories aren't really such entities: they are just
Linus Walleij387e37a2008-10-29 17:22:22 +0000746objects too, albeit objects that can act as parent to other
Linus Walleij8aba06d2008-12-28 08:26:57 +0000747objects. They are called "associations" and are created in atomic
Linus Walleij387e37a2008-10-29 17:22:22 +0000748fashion and even though there is an MTP command to get all the
Linus Walleij8aba06d2008-12-28 08:26:57 +0000749associations of a certain association, this command is optional
750so it is perfectly possible (and most common, actually) to create
751devices where the "folders" (which are actually associations) have
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000752no idea whatsoever of what files they are associated as parents to
Linus Walleij387e37a2008-10-29 17:22:22 +0000753(i.e. which files they contain). This is very easy for device
Linus Walleij8aba06d2008-12-28 08:26:57 +0000754manufacturers to implement, all the association (i.e. finding out
755which files are in a certain folder) has to be done by the MTP
756Initiator / host computer.
Linus Walleij387e37a2008-10-29 17:22:22 +0000757
758Moving a file to a new folder is for example very simple in a
759"real" file system. In PTP/MTP devices it is often not even possible,
760some devices *may* be able to do that. But actually the only
761reliable way of doing that is to upload the file to the host,
Linus Walleij8aba06d2008-12-28 08:26:57 +0000762download it with the new parent, then delete the old file.
Linus Walleij387e37a2008-10-29 17:22:22 +0000763We have played with the idea of implementing this time consuming
764function, perhaps we will.
765
Linus Walleij8aba06d2008-12-28 08:26:57 +0000766Then the issue that in PTP/MTP it is legal for two files to have
767exactly the same path as long as their object IDs differ. A
768folder/association can contain two files with the exact same name.
769(And on the Creative devices this even works, too, though most devices
770implicitly fail at this.) Perhaps one could add some custom hook for
771handling that, so they become /Foo.mp3 and /Foo.mp3(1) or something
772similar, but it's really a bit kludgy.
773
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000774Playlists and albums aren't really files, thinking about
Linus Walleij387e37a2008-10-29 17:22:22 +0000775them as files like the hacks in libgphoto2 is really backwards. They are
776called associations and are more like a symbolic link that links in a
777star-shaped pattern to all the files that are part of the album/playlist.
778Some devices (Samsung) thought that was too complicated and have a
779different way of storing playlists in an UTF-16 encoded .spl-like file
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000780instead! This is why playlists/albums must have their own structs and
Linus Walleij387e37a2008-10-29 17:22:22 +0000781functions.
782
Linus Walleij8aba06d2008-12-28 08:26:57 +0000783Plain file access also assumes to be able to write files of an
784undetermined size, which is simply not possible in a transactional
785file system like PTP/MTP. (See further below.)
786
Linus Walleij387e37a2008-10-29 17:22:22 +0000787
788I Want Streaming!
789-----------------
790
791Streaming reads is easy. Just connect the output file descriptor from
792LIBMTP_Get_File_To_File_Descriptor() (and a similar function for tracks)
793wherever you want.
794
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000795People have connected this to TCP sockets for streaming web servers
796etc, works like a charm. Some devices will even survive if the callback
Linus Walleij387e37a2008-10-29 17:22:22 +0000797functions return non-zero and cancel the download. Some devices will
798lock up and even require a reset if you do that. Devices are poorly
799implemented so that's life. If you want to stream off a device, the
800best idea is always to stream the entire file and discard the stuff
801at the end you don't want. It will incur a delay if you e.g. want to
802skip between tracks, sadly.
803
804Then we get to the complicated things: streaming WRITES...
805
806There is a function:
807LIBMTP_Send_File_From_File_Descriptor() (and similar for tracks)
808which will write a file to a device from a file descriptor, which may
809be a socket or whatever.
810
811HOWEVER: this requires a piece of metadata with the .filesize properly
812set first.
813
814This is not because we think it is funny to require that, the protocol
815requires it. The reason is that PTP/MTP is a transactional file system
816and it wants to be able to deny file transfer if the file won't fit on
817the device, so the transaction never even starts, it's impossible to
818start a transaction without giving file length.
819
820People really want streaming so I tried a lot of hacks to see if they
821would work, such as setting file size to 0xffffffffU or something other
822unnaturally big and then aborting the file transfer when the stream ends.
823It doesn't work: either the device crashes or the file simply disappears
824since the device rolls back all failed transactions.
825
826So this is an inherent limitation of the PTP/MTP protocol.
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000827
828
Linus Walleijae890212012-02-16 01:56:19 +0100829I want to remote control my device!
830-----------------------------------
831
832I have both good and bad news for you.
833
834The good news is that the MTP protocol has well-defined commands to play
835back content on a device. Operation 0xD411 (PTP_DPC_MTP_PlaybackObject)
836will start playing back a file on the device (whatever that may mean if
837this is not a music or video file), and operation 0xD403 can set the
838playback volume to save your ears. Then there are operations to
839determine how far into the current file you currently are, so as to
840support say progress bars.
841
842Since these commands have been around since the dawn of the MTP protocol
843and since it was developed in cooperation with Creative Technology, this
844is probably a requested feature from the Creative people who already had
845support for playback on their devices using the PDE protocol back then.
846
847Anyway, here are the bad news:
848[logs]$ grep d411 *
849mtp-detect-trekstor-vibez.txt: 0xd411: Playback Object
850
851Aha there is only one known device in the world which actually supports
852playback on the device. So either you go buy the Trekstor Vibez, or you
853can forget about this. You could always try asking your hardware vendor
854of choice to go implement this.
855
856Since none of the core developers of libmtp has the Trekstor device, this
857is not yet implemented in libmtp.
858
859
Linus Walleijbe8b03b2009-10-16 21:19:35 +0000860I make MTP devices!
861-------------------
862
863If you are a device vendor there is a lot you can do for libmtp:
864
865* Please consider assigning one of your employees as a contact person
866 for libmtp, have them sign up to the libmtp development list and answer
867 questions and post new device ID:s as they are released to our
868 mailing list.
869
870* If you want to help even more, assign someone to look deeper into
871 error reports on your specific devices, understand why your firmware
872 may require some special device flags and what can be done about it.
873
874* Do you have spare devices you can give us? Send them to Richard (Mac
875 support) or Linus (Linux support). (So far nobody did that except for
876 Microsoft who sent us a Zune by proxy!)
877
878Vendors do need help from libmtp too, especially we want to help
879vendors improve their MTP stacks, because they all suffer from the
880same problem: the lack of a proper conformance test has made many devices
881incompliant with the MTP specification as it is published today: most
882devices are just compliant with the Windows MTP stack, and don't work
883out-of-the-box with libmtp. We need someone on the inside to help in
884bug reporting vendors MTP stacks internally so these issues are raised.
885A good way to go toward better MTP compliance is to test with an
886alternative implementation of the stack. In e.g. IETF standardization
887it is compulsory for an RFC to have atleast two independent implementations
888for it to reach the status as standard.
889
890Being compliant with libmtp is also more and more important for
891vendors: libmtp is being deployed in some embedded systems like
892set-top-boxes etc. It will be very irritating for customers if a device
893will not dock properly with some home entertainment equipment just because
894it is based on Linux and libmtp and not the Windows MTP stack.
Linus Walleij5f5c69f2011-06-26 14:34:13 +0200895
896Autodetect with gudev
897---------------------
898
899Previously you would use HAL to detect devices being plugged in. Nowadays
900we use udev directly, or though the GNOME libgudev library. LIBMTPs
901default udev rules export the proper properties to detect any MTP device
902automatically, here is a verbose example derived from gnomad2:
903
904#define G_UDEV_API_IS_SUBJECT_TO_CHANGE
905#include <gudev/gudev.h>
906const char * const gudev_subsystems[] = { "usb", NULL };
907GUdevClient *gudev_client;
908guint uevent_id;
909guint uevent_bus_hooked = 0;
910guint uevent_device_hooked = 0;
911
912
913static void uevent_cb(GUdevClient *client, const char *action, GUdevDevice *device, void *data)
914{
915 guint64 devicenum;
916 guint vendor;
917 guint model;
918 guint busnum;
919 guint devnum;
920 guint mtpdevice;
921
922 devicenum = (guint64) g_udev_device_get_device_number(device);
923 g_print("%s event for %s (%"G_GINT64_MODIFIER"x)", action,
924 g_udev_device_get_sysfs_path (device), devicenum);
925
926 /* get device info */
927 vendor = get_property_as_int(device, "ID_VENDOR_ID", 16);
928 model = get_property_as_int(device, "ID_MODEL_ID", 16);
929 busnum = get_property_as_int(device, "BUSNUM", 10);
930 devnum = get_property_as_int(device, "DEVNUM", 10);
931 mtpdevice = get_property_as_int(device, "ID_MTP_DEVICE", 10);
932
933 if (vendor == 0 || model == 0) {
934 g_print("couldn't get vendor or model ID for device at (%x:%x)\n",
935 busnum, devnum);
936 return;
937 } else {
938 g_print("vendor = %x, model = %x, bus = %x, device = %x\n",
939 vendor, model, busnum, devnum);
940 }
941
942 if (mtpdevice) {
943 g_print("device is MTP compliant\n");
944
945 if (g_str_equal(action, "add") &&
946 uevent_bus_hooked == 0 &&
947 uevent_device_hooked == 0) {
948 g_print(MTP device plugged in!\n");
949 uevent_bus_hooked = busnum;
950 uevent_device_hooked = devnum;
951 scan_jukebox(NULL);
952 } else if (g_str_equal (action, "remove") &&
953 uevent_bus_hooked == busnum &&
954 uevent_device_hooked == devnum) {
955 g_print("MTP device removed!\n");
956 uevent_bus_hooked = 0;
957 uevent_device_hooked = 0;
958 }
959 }
960}
961
962
963
964(...)
965 /*
966 * Monitor udev device events - we're only really interested in events
967 * for USB devices.
968 */
969 gudev_client = g_udev_client_new(gudev_subsystems);
970 uevent_id = g_signal_connect_object(gudev_client,
971 "uevent",
972 G_CALLBACK(uevent_cb),
973 NULL, 0);
Linus Walleij187ac2f2012-05-02 19:08:03 +0200974
975SKETCH OF AN OVERVIEW
976---------------------
977
978Draft agenda for a talk on MTP devices submitted for the Android
979builders summit, might come to recycle this:
980
981- Protocol overview
982- libmtp interface
983- relation to libgphoto2
984- Device sins
985 - Android bugs
986 - Samsungs special Android MTP stack
987 - SonyEricsson Aricent stack for Xperia Androids pre 4.0, broken headers!
988- Detecting from vendor extension, can fix in newer extensions!
989- Autoprobing on Linux
990 - Color devices do not like autoprobing
991- Ideas??
992- Mode switch devices?
993- MTPZ