Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | $Id: README.aztcd,v 2.60 1997/11/29 09:51:25 root Exp root $ |
| 2 | Readme-File Documentation/cdrom/aztcd |
| 3 | for |
| 4 | AZTECH CD-ROM CDA268-01A, ORCHID CD-3110, |
| 5 | OKANO/WEARNES CDD110, CONRAD TXC, CyCDROM CR520, CR540 |
| 6 | CD-ROM Drives |
| 7 | Version 2.6 and newer |
| 8 | (for other drives see 6.-8.) |
| 9 | |
| 10 | NOTE: THIS DRIVER WILL WORK WITH THE CD-ROM DRIVES LISTED, WHICH HAVE |
| 11 | A PROPRIETARY INTERFACE (implemented on a sound card or on an |
| 12 | ISA-AT-bus card). |
| 13 | IT WILL DEFINITELY NOT WORK WITH CD-ROM DRIVES WITH *IDE*-INTERFACE, |
| 14 | such as the Aztech CDA269-031SE !!! (The only known exceptions are |
| 15 | 'faked' IDE drives like the CyCDROM CR520ie which work with aztcd |
| 16 | under certain conditions, see 7.). IF YOU'RE USING A CD-ROM DRIVE |
| 17 | WITH IDE-INTERFACE, SOMETIMES ALSO CALLED ATAPI-COMPATIBLE, PLEASE |
| 18 | USE THE ide-cd.c DRIVER, WRITTEN BY MARK LORD AND SCOTT SNYDER ! |
| 19 | THE STANDARD-KERNEL 1.2.x NOW ALSO SUPPORTS IDE-CDROM-DRIVES, SEE THE |
| 20 | HARDDISK (!) SECTION OF make config, WHEN COMPILING A NEW KERNEL!!! |
| 21 | ---------------------------------------------------------------------------- |
| 22 | |
| 23 | Contents of this file: |
| 24 | 1. NOTE |
| 25 | 2. INSTALLATION |
| 26 | 3. CONFIGURING YOUR KERNEL |
| 27 | 4. RECOMPILING YOUR KERNEL |
| 28 | 4.1 AZTCD AS A RUN-TIME LOADABLE MODULE |
| 29 | 4.2 CDROM CONNECTED TO A SOUNDCARD |
| 30 | 5. KNOWN PROBLEMS, FUTURE DEVELOPMENTS |
| 31 | 5.1 MULTISESSION SUPPORT |
| 32 | 5.2 STATUS RECOGNITION |
| 33 | 5.3 DOSEMU's CDROM SUPPORT |
| 34 | 6. BUG REPORTS |
| 35 | 7. OTHER DRIVES |
| 36 | 8. IF YOU DON'T SUCCEED ... DEBUGGING |
| 37 | 9. TECHNICAL HISTORY OF THE DRIVER |
| 38 | 10. ACKNOWLEDGMENTS |
| 39 | 11. PROGRAMMING ADD ONS: CDPLAY.C |
| 40 | APPENDIX: Source code of cdplay.c |
| 41 | ---------------------------------------------------------------------------- |
| 42 | |
| 43 | 1. NOTE |
| 44 | This software has been successfully in alpha and beta test and is part of |
| 45 | the standard kernel since kernel 1.1.8x since December 1994. It works with |
| 46 | AZTECH CDA268-01A, ORCHID CDS-3110, ORCHID/WEARNES CDD110 and CONRAD TXC |
| 47 | (Nr.99 31 23 -series 04) and has proven to be stable with kernel |
| 48 | versions 1.0.9 and newer. But with any software there still may be bugs in it. |
| 49 | So if you encounter problems, you are invited to help us improve this software. |
| 50 | Please send me a detailed bug report (see chapter BUG REPORTS). You are also |
| 51 | invited in helping us to increase the number of drives, which are supported. |
| 52 | |
| 53 | Please read the README-files carefully and always keep a backup copy of your |
| 54 | old kernel, in order to reboot if something goes wrong! |
| 55 | |
| 56 | 2. INSTALLATION |
| 57 | The driver consists of a header file 'aztcd.h', which normally should reside |
| 58 | in /usr/src/linux/drivers/cdrom and the source code 'aztcd.c', which normally |
| 59 | resides in the same place. It uses /dev/aztcd (/dev/aztcd0 in some distri- |
| 60 | butions), which must be a valid block device with major number 29 and reside |
| 61 | in directory /dev. To mount a CD-ROM, your kernel needs to have the ISO9660- |
| 62 | filesystem support included. |
| 63 | |
| 64 | PLEASE NOTE: aztcd.c has been developed in parallel to the linux kernel, |
| 65 | which had and is having many major and minor changes which are not backward |
| 66 | compatible. Quite definitely aztcd.c version 1.80 and newer will NOT work |
| 67 | in kernels older than 1.3.33. So please always use the most recent version |
| 68 | of aztcd.c with the appropriate linux-kernel. |
| 69 | |
| 70 | 3. CONFIGURING YOUR KERNEL |
| 71 | If your kernel is already configured for using the AZTECH driver you will |
| 72 | see the following message while Linux boots: |
| 73 | Aztech CD-ROM Init: DriverVersion=<version number> BaseAddress=<baseaddress> |
| 74 | Aztech CD-ROM Init: FirmwareVersion=<firmware version id of your I/O-card>>> |
| 75 | Aztech CD-ROM Init: <drive type> detected |
| 76 | Aztech CD-ROM Init: End |
| 77 | If the message looks different and you are sure to have a supported drive, |
| 78 | it may have a different base address. The Aztech driver does look for the |
| 79 | CD-ROM drive at the base address specified in aztcd.h at compile time. This |
| 80 | address can be overwritten by boot parameter aztcd=....You should reboot and |
| 81 | start Linux with boot parameter aztcd=<base address>, e.g. aztcd=0x320. If |
| 82 | you do not know the base address, start your PC with DOS and look at the boot |
| 83 | message of your CD-ROM's DOS driver. If that still does not help, use boot |
| 84 | parameter aztcd=<base address>,0x79 , this tells aztcd to try a little harder. |
| 85 | aztcd may be configured to use autoprobing the base address by recompiling |
| 86 | it (see chapter 4.). |
| 87 | |
| 88 | If the message looks correct, as user 'root' you should be able to mount the |
| 89 | drive by |
| 90 | mount -t iso9660 -r /dev/aztcd0 /mnt |
| 91 | and use it as any other filesystem. (If this does not work, check if |
| 92 | /dev/aztcd0 and /mnt do exist and create them, if necessary by doing |
| 93 | mknod /dev/aztcd0 b 29 0 |
| 94 | mkdir /mnt |
| 95 | |
| 96 | If you still get a different message while Linux boots or when you get the |
| 97 | message, that the ISO9660-filesystem is not supported by your kernel, when |
| 98 | you try to mount the CD-ROM drive, you have to recompile your kernel. |
| 99 | |
| 100 | If you do *not* have an Aztech/Orchid/Okano/Wearnes/TXC drive and want to |
| 101 | bypass drive detection during Linux boot up, start with boot parameter aztcd=0. |
| 102 | |
| 103 | Most distributions nowadays do contain a boot disk image containing aztcd. |
| 104 | Please note, that this driver will not work with IDE/ATAPI drives! With these |
| 105 | you must use ide-cd.c instead. |
| 106 | |
| 107 | 4. RECOMPILING YOUR KERNEL |
| 108 | If your kernel is not yet configured for the AZTECH driver and the ISO9660- |
| 109 | filesystem, you have to recompile your kernel: |
| 110 | |
| 111 | - Edit aztcd.h to set the I/O-address to your I/O-Base address (AZT_BASE_ADDR), |
| 112 | the driver does not use interrupts or DMA, so if you are using an AZTECH |
| 113 | CD268, an ORCHID CD-3110 or ORCHID/WEARNES CDD110 that's the only item you |
| 114 | have to set up. If you have a soundcard, read chapter 4.2. |
| 115 | Users of other drives should read chapter OTHER DRIVES of this file. |
| 116 | You also can configure that address by kernel boot parameter aztcd=... |
| 117 | - aztcd may be configured to use autoprobing the base address by setting |
| 118 | AZT_BASE_ADDR to '-1'. In that case aztcd probes the addresses listed |
| 119 | under AZT_BASE_AUTO. But please remember, that autoprobing always may |
| 120 | incorrectly influence other hardware components too! |
| 121 | - There are some other points, which may be configured, e.g. auto-eject the |
| 122 | CD when unmounting a drive, tray locking etc., see aztcd.h for details. |
| 123 | - If you're using a linux kernel version prior to 2.1.0, in aztcd.h |
| 124 | uncomment the line '#define AZT_KERNEL_PRIOR_2_1' |
| 125 | - Build a new kernel, configure it for 'Aztech/Orchid/Okano/Wearnes support' |
| 126 | (if you want aztcd to be part of the kernel). Do not configure it for |
| 127 | 'Aztech... support', if you want to use aztcd as a run time loadable module. |
| 128 | But in any case you must have the ISO9660-filesystem included in your |
| 129 | kernel. |
| 130 | - Activate the new kernel, normally this is done by running LILO (don't for- |
| 131 | get to configure it before and to keep a copy of your old kernel in case |
| 132 | something goes wrong!). |
| 133 | - Reboot |
| 134 | - If you've included aztcd in your kernel, you now should see during boot |
| 135 | some messages like |
| 136 | Aztech CD-ROM Init: DriverVersion=<version number> BaseAddress=<baseaddress> |
| 137 | Aztech CD-ROM Init: FirmwareVersion=<firmware version id of your I/O-card> |
| 138 | Aztech CD-ROM Init: <drive type> detected |
| 139 | Aztech CD-ROM Init: End |
| 140 | - If you have not included aztcd in your kernel, but want to load aztcd as a |
| 141 | run time loadable module see 4.1. |
| 142 | - If the message looks correct, as user 'root' you should be able to mount |
| 143 | the drive by |
| 144 | mount -t iso9660 -r /dev/aztcd0 /mnt |
| 145 | and use it as any other filesystem. (If this does not work, check if |
| 146 | /dev/aztcd0 and /mnt do exist and create them, if necessary by doing |
| 147 | mknod /dev/aztcd0 b 29 0 |
| 148 | mkdir /mnt |
| 149 | - If this still does not help, see chapters OTHER DRIVES and DEBUGGING. |
| 150 | |
| 151 | 4.1 AZTCD AS A RUN-TIME LOADABLE MODULE |
| 152 | If you do not need aztcd permanently, you can also load and remove the driver |
| 153 | during runtime via insmod and rmmod. To build aztcd as a loadable module you |
| 154 | must configure your kernel for AZTECH module support (answer 'm' when con- |
| 155 | figuring the kernel). Anyhow, you may run into problems, if the version of |
| 156 | your boot kernel is not the same than the source kernel version, from which |
| 157 | you create the modules. So rebuild your kernel, if necessary. |
| 158 | |
| 159 | Now edit the base address of your AZTECH interface card in |
| 160 | /usr/src/linux/drivers/cdrom/aztcd.h to the appropriate value. |
| 161 | aztcd may be configured to use autoprobing the base address by setting |
| 162 | AZT_BASE_ADDR to '-1'. In that case aztcd probes the addresses listed |
| 163 | under AZT_BASE_AUTO. But please remember, that autoprobing always may |
| 164 | incorrectly influence other hardware components too! |
| 165 | There are also some special features which may be configured, e.g. |
| 166 | auto-eject a CD when unmounting the drive etc; see aztcd.h for details. |
| 167 | Then change to /usr/src/linux and do a |
| 168 | make modules |
| 169 | make modules_install |
| 170 | After that you can run-time load the driver via |
| 171 | insmod /lib/modules/X.X.X/misc/aztcd.o |
| 172 | and remove it via rmmod aztcd. |
| 173 | If you did not set the correct base address in aztcd.h, you can also supply the |
| 174 | base address when loading the driver via |
| 175 | insmod /lib/modules/X.X.X/misc/aztcd.o aztcd=<base address> |
| 176 | Again specifying aztcd=-1 will cause autoprobing. |
| 177 | If you do not have the iso9660-filesystem in your boot kernel, you also have |
| 178 | to load it before you can mount the CDROM: |
| 179 | insmod /lib/modules/X.X.X/fs/isofs.o |
| 180 | The mount procedure works as described in 4. above. |
| 181 | (In all commands 'X.X.X' is the current linux kernel version number) |
| 182 | |
| 183 | 4.2 CDROM CONNECTED TO A SOUNDCARD |
| 184 | Most soundcards do have a bus interface to the CDROM-drive. In many cases |
| 185 | this soundcard needs to be configured, before the CDROM can be used. This |
| 186 | configuration procedure consists of writing some kind of initialization |
| 187 | data to the soundcard registers. The AZTECH-CDROM driver in the moment does |
| 188 | only support one type of soundcard (SoundWave32). Users of other soundcards |
| 189 | should try to boot DOS first and let their DOS drivers initialize the |
| 190 | soundcard and CDROM, then warm boot (or use loadlin) their PC to start |
| 191 | Linux. |
| 192 | Support for the CDROM-interface of SoundWave32-soundcards is directly |
| 193 | implemented in the AZTECH driver. Please edit linux/drivers/cdrom/aztdc.h, |
| 194 | uncomment line '#define AZT_SW32' and set the appropriate value for |
| 195 | AZT_BASE_ADDR and AZT_SW32_BASE_ADDR. This support was tested with an Orchid |
| 196 | CDS-3110 connected to a SoundWave32. |
| 197 | If you want your soundcard to be supported, find out, how it needs to be |
| 198 | configured and mail me (see 6.) the appropriate information. |
| 199 | |
| 200 | 5. KNOWN PROBLEMS, FUTURE DEVELOPMENTS |
| 201 | 5.1 MULTISESSION SUPPORT |
| 202 | Multisession support for CD's still is a myth. I implemented and tested a basic |
| 203 | support for multisession and XA CDs, but I still have not enough CDs and appli- |
| 204 | cations to test it rigorously. So if you'd like to help me, please contact me |
| 205 | (Email address see below). As of version 1.4 and newer you can enable the |
| 206 | multisession support in aztcd.h by setting AZT_MULTISESSION to 1. Doing so |
| 207 | will cause the ISO9660-filesystem to deal with multisession CDs, ie. redirect |
| 208 | requests to the Table of Contents (TOC) information from the last session, |
| 209 | which contains the info of all previous sessions etc.. If you do set |
| 210 | AZT_MULTISESSION to 0, you can use multisession CDs anyway. In that case the |
| 211 | drive's firmware will do automatic redirection. For the ISO9660-filesystem any |
| 212 | multisession CD will then look like a 'normal' single session CD. But never- |
| 213 | theless the data of all sessions are viewable and accessible. So with practical- |
| 214 | ly all real world applications you won't notice the difference. But as future |
| 215 | applications may make use of advanced multisession features, I've started to |
| 216 | implement the interface for the ISO9660 multisession interface via ioctl |
| 217 | CDROMMULTISESSION. |
| 218 | |
| 219 | 5.2 STATUS RECOGNITION |
| 220 | The drive status recognition does not work correctly in all cases. Changing |
| 221 | a disk or having the door open, when a drive is already mounted, is detected |
| 222 | by the Aztech driver itself, but nevertheless causes multiple read attempts |
| 223 | by the different layers of the ISO9660-filesystem driver, which finally timeout, |
| 224 | so you have to wait quite a little... But isn't it bad style to change a disk |
| 225 | in a mounted drive, anyhow ?! |
| 226 | |
| 227 | The driver uses busy wait in most cases for the drive handshake (macros |
| 228 | STEN_LOW and DTEN_LOW). I tested with a 486/DX2 at 66MHz and a Pentium at |
| 229 | 60MHz and 90MHz. Whenever you use a much faster machine you are likely to get |
| 230 | timeout messages. In that case edit aztcd.h and increase the timeout value |
| 231 | AZT_TIMEOUT. |
| 232 | |
| 233 | For some 'slow' drive commands I implemented waiting with a timer waitqueue |
| 234 | (macro STEN_LOW_WAIT). If you get this timeout message, you may also edit |
| 235 | aztcd.h and increase the timeout value AZT_STATUS_DELAY. The waitqueue has |
| 236 | shown to be a little critical. If you get kernel panic messages, edit aztcd.c |
| 237 | and substitute STEN_LOW_WAIT by STEN_LOW. Busy waiting with STEN_LOW is more |
| 238 | stable, but also causes CPU overhead. |
| 239 | |
| 240 | 5.3 DOSEMU's CD-ROM SUPPORT |
| 241 | With release 1.20 aztcd was modified to allow access to CD-ROMS when running |
| 242 | under dosemu-0.60.0 aztcd-versions before 1.20 are most likely to crash |
| 243 | Linux, when a CD-ROM is accessed under dosemu. This problem has partly been |
| 244 | fixed, but still when accessing a directory for the first time the system |
| 245 | might hang for some 30sec. So be patient, when using dosemu's CD-ROM support |
| 246 | in combination with aztcd :-) ! |
| 247 | This problem has now (July 1995) been fixed by a modification to dosemu's |
| 248 | CD-ROM driver. The new version came with dosemu-0.60.2, see dosemu's |
| 249 | README.CDROM. |
| 250 | |
| 251 | 6. BUG REPORTS |
| 252 | Please send detailed bug reports and bug fixes via EMail to |
| 253 | |
| 254 | Werner.Zimmermann@fht-esslingen.de |
| 255 | |
| 256 | Please include a description of your CD-ROM drive type and interface card, |
| 257 | the exact firmware message during Linux bootup, the version number of the |
| 258 | AZTECH-CDROM-driver and the Linux kernel version. Also a description of your |
| 259 | system's other hardware could be of interest, especially microprocessor type, |
| 260 | clock frequency, other interface cards such as soundcards, ethernet adapter, |
| 261 | game cards etc.. |
| 262 | |
| 263 | I will try to collect the reports and make the necessary modifications from |
| 264 | time to time. I may also come back to you directly with some bug fixes and |
| 265 | ask you to do further testing and debugging. |
| 266 | |
| 267 | Editors of CD-ROMs are invited to send a 'cooperation' copy of their |
| 268 | CD-ROMs to the volunteers, who provided the CD-ROM support for Linux. My |
| 269 | snail mail address for such 'stuff' is |
| 270 | Prof. Dr. W. Zimmermann |
| 271 | Fachhochschule fuer Technik Esslingen |
| 272 | Fachbereich IT |
| 273 | Flandernstrasse 101 |
| 274 | D-73732 Esslingen |
| 275 | Germany |
| 276 | |
| 277 | |
| 278 | 7. OTHER DRIVES |
| 279 | The following drives ORCHID CDS3110, OKANO CDD110, WEARNES CDD110 and Conrad |
| 280 | TXC Nr. 993123-series 04 nearly look the same as AZTECH CDA268-01A, especially |
| 281 | they seem to use the same command codes. So it was quite simple to make the |
| 282 | AZTECH driver work with these drives. |
| 283 | |
| 284 | Unfortunately I do not have any of these drives available, so I couldn't test |
| 285 | it myself. In some installations, it seems necessary to initialize the drive |
| 286 | with the DOS driver before (especially if combined with a sound card) and then |
| 287 | do a warm boot (CTRL-ALT-RESET) or start Linux from DOS, e.g. with 'loadlin'. |
| 288 | |
| 289 | If you do not succeed, read chapter DEBUGGING. Thanks in advance! |
| 290 | |
| 291 | Sorry for the inconvenience, but it is difficult to develop for hardware, |
| 292 | which you don't have available for testing. So if you like, please help us. |
| 293 | |
| 294 | If you do have a CyCDROM CR520ie thanks to Hilmar Berger's help your chances |
| 295 | are good, that it will work with aztcd. The CR520ie is sold as an IDE-drive |
| 296 | and really is connected to the IDE interface (primary at 0x1F0 or secondary |
| 297 | at 0x170, configured as slave, not as master). Nevertheless it is not ATAPI |
| 298 | compatible but still uses Aztech's command codes. |
| 299 | |
| 300 | |
| 301 | 8. DEBUGGING : IF YOU DON'T SUCCEED, TRY THE FOLLOWING |
| 302 | -reread the complete README file |
| 303 | -make sure, that your drive is hardware configured for |
| 304 | transfer mode: polled |
| 305 | IRQ: not used |
| 306 | DMA: not used |
| 307 | Base Address: something like 300, 320 ... |
| 308 | You can check this, when you start the DOS driver, which came with your |
| 309 | drive. By appropriately configuring the drive and the DOS driver you can |
| 310 | check, whether your drive does operate in this mode correctly under DOS. If |
| 311 | it does not operate under DOS, it won't under Linux. |
| 312 | If your drive's base address is something like 0x170 or 0x1F0 (and it is |
| 313 | not a CyCDROM CR520ie or CR 940ie) you most likely are having an IDE/ATAPI- |
| 314 | compatible drive, which is not supported by aztcd.c, use ide-cd.c instead. |
| 315 | Make sure the Base Address is configured correctly in aztcd.h, also make |
| 316 | sure, that /dev/aztcd0 exists with the correct major number (compare it with |
| 317 | the entry in file /usr/include/linux/major.h for the Aztech drive). |
| 318 | -insert a CD-ROM and close the tray |
| 319 | -cold boot your PC (i.e. via the power on switch or the reset button) |
| 320 | -if you start Linux via DOS, e.g. using loadlin, make sure, that the DOS |
| 321 | driver for the CD-ROM drive is not loaded (comment out the calling lines |
| 322 | in DOS' config.sys!) |
| 323 | -look for the aztcd: init message during Linux init and note them exactly |
| 324 | -log in as root and do a mount -t iso9660 /dev/aztcd0 /mnt |
| 325 | -if you don't succeed in the first time, try several times. Try also to open |
| 326 | and close the tray, then mount again. Please note carefully all commands |
| 327 | you typed in and the aztcd-messages, which you get. |
| 328 | -if you get an 'Aztech CD-ROM init: aborted' message, read the remarks about |
| 329 | the version string below. |
| 330 | |
| 331 | If this does not help, do the same with the following differences |
| 332 | -start DOS before; make now sure, that the DOS driver for the CD-ROM is |
| 333 | loaded under DOS (i.e. uncomment it again in config.sys) |
| 334 | -warm boot your PC (i.e. via CTRL-ALT-DEL) |
| 335 | if you have it, you can also start via loadlin (try both). |
| 336 | ... |
| 337 | Again note all commands and the aztcd-messages. |
| 338 | |
| 339 | If you see STEN_LOW or STEN_LOW_WAIT error messages, increase the timeout |
| 340 | values. |
| 341 | |
| 342 | If this still does not help, |
| 343 | -look in aztcd.c for the lines #if 0 |
| 344 | #define AZT_TEST1 |
| 345 | ... |
| 346 | #endif |
| 347 | and substitute '#if 0' by '#if 1'. |
| 348 | -recompile your kernel and repeat the above two procedures. You will now get |
| 349 | a bundle of debugging messages from the driver. Again note your commands |
| 350 | and the appropriate messages. If you have syslogd running, these messages |
| 351 | may also be found in syslogd's kernel log file. Nevertheless in some |
| 352 | installations syslogd does not yet run, when init() is called, thus look for |
| 353 | the aztcd-messages during init, before the login-prompt appears. |
| 354 | Then look in aztcd.c, to find out, what happened. The normal calling sequence |
| 355 | is: aztcd_init() during Linux bootup procedure init() |
| 356 | after doing a 'mount -t iso9660 /dev/aztcd0 /mnt' the normal calling sequence is |
| 357 | aztcd_open() -> Status 2c after cold reboot with CDROM or audio CD inserted |
| 358 | -> Status 8 after warm reboot with CDROM inserted |
| 359 | -> Status 2e after cold reboot with no disk, closed tray |
| 360 | -> Status 6e after cold reboot, mount with door open |
| 361 | aztUpdateToc() |
| 362 | aztGetDiskInfo() |
| 363 | aztGetQChannelInfo() repeated several times |
| 364 | aztGetToc() |
| 365 | aztGetQChannelInfo() repeated several times |
| 366 | a list of track information |
| 367 | do_aztcd_request() } |
| 368 | azt_transfer() } repeated several times |
| 369 | azt_poll } |
| 370 | Check, if there is a difference in the calling sequence or the status flags! |
| 371 | |
| 372 | There are a lot of other messages, eg. the ACMD-command code (defined in |
| 373 | aztcd.h), status info from the getAztStatus-command and the state sequence of |
| 374 | the finite state machine in azt_poll(). The most important are the status |
| 375 | messages, look how they are defined and try to understand, if they make |
| 376 | sense in the context where they appear. With a CD-ROM inserted the status |
| 377 | should always be 8, except in aztcd_open(). Try to open the tray, insert an |
| 378 | audio disk, insert no disk or reinsert the CD-ROM and check, if the status |
| 379 | bits change accordingly. The status bits are the most likely point, where |
| 380 | the drive manufacturers may implement changes. |
| 381 | |
| 382 | If you still don't succeed, a good point to start is to look in aztcd.c in |
| 383 | function aztcd_init, where the drive should be detected during init. Do the |
| 384 | following: |
| 385 | -reboot the system with boot parameter 'aztcd=<your base address>,0x79'. With |
| 386 | parameter 0x79 most of the drive version detection is bypassed. After that |
| 387 | you should see the complete version string including leading and trailing |
| 388 | blanks during init. |
| 389 | Now adapt the statement |
| 390 | if ((result[1]=='A')&&(result[2]=='Z' ...) |
| 391 | in aztcd_init() to exactly match the first 3 or 4 letters you have seen. |
| 392 | -Another point is the 'smart' card detection feature in aztcd_init(). Normally |
| 393 | the CD-ROM drive is ready, when aztcd_init is trying to read the version |
| 394 | string and a time consuming ACMD_SOFT_RESET command can be avoided. This is |
| 395 | detected by looking, if AFL_OP_OK can be read correctly. If the CD-ROM drive |
| 396 | hangs in some unknown state, e.g. because of an error before a warm start or |
| 397 | because you first operated under DOS, even the version string may be correct, |
| 398 | but the following commands will not. Then change the code in such a way, |
| 399 | that the ACMD_SOFT_RESET is issued in any case, by substituting the |
| 400 | if-statement 'if ( ...=AFL_OP_OK)' by 'if (1)'. |
| 401 | |
| 402 | If you succeed, please mail me the exact version string of your drive and |
| 403 | the code modifications, you have made together with a short explanation. |
| 404 | If you don't succeed, you may mail me the output of the debugging messages. |
| 405 | But remember, they are only useful, if they are exact and complete and you |
| 406 | describe in detail your hardware setup and what you did (cold/warm reboot, |
| 407 | with/without DOS, DOS-driver started/not started, which Linux-commands etc.) |
| 408 | |
| 409 | |
| 410 | 9. TECHNICAL HISTORY OF THE DRIVER |
| 411 | The AZTECH-Driver is a rework of the Mitsumi-Driver. Four major items had to |
| 412 | be reworked: |
| 413 | |
| 414 | a) The Mitsumi drive does issue complete status information acknowledging |
| 415 | each command, the Aztech drive does only signal that the command was |
| 416 | processed. So whenever the complete status information is needed, an extra |
| 417 | ACMD_GET_STATUS command is issued. The handshake procedure for the drive |
| 418 | can be found in the functions aztSendCmd(), sendAztCmd() and getAztStatus(). |
| 419 | |
| 420 | b) The Aztech Drive does not have a ACMD_GET_DISK_INFO command, so the |
| 421 | necessary info about the number of tracks (firstTrack, lastTrack), disk |
| 422 | length etc. has to be read from the TOC in the lead in track (see function |
| 423 | aztGetDiskInfo()). |
| 424 | |
| 425 | c) Whenever data is read from the drive, the Mitsumi drive is started with a |
| 426 | command to read an indefinite (0xffffff) number of sectors. When the appropriate |
| 427 | number of sectors is read, the drive is stopped by a ACDM_STOP command. This |
| 428 | does not work with the Aztech drive. I did not find a way to stop it. The |
| 429 | stop and pause commands do only work in AUDIO mode but not in DATA mode. |
| 430 | Therefore I had to modify the 'finite state machine' in function azt_poll to |
| 431 | only read a certain number of sectors and then start a new read on demand. As I |
| 432 | have not completely understood, how the buffer/caching scheme of the Mitsumi |
| 433 | driver was implemented, I am not sure, if I have covered all cases correctly, |
| 434 | whenever you get timeout messages, the bug is most likely to be in that |
| 435 | function azt_poll() around switch(cmd) .... case ACD_S_DATA. |
| 436 | |
| 437 | d) I did not get information about changing drive mode. So I doubt, that the |
| 438 | code around function azt_poll() case AZT_S_MODE does work. In my test I have |
| 439 | not been able to switch to reading in raw mode. For reading raw mode, Aztech |
| 440 | uses a different command than for cooked mode, which I only have implemen- |
| 441 | ted in the ioctl-section but not in the section which is used by the ISO9660. |
| 442 | |
| 443 | The driver was developed on an AST PC with Intel 486/DX2, 8MB RAM, 340MB IDE |
| 444 | hard disk and on an AST PC with Intel Pentium 60MHz, 16MB RAM, 520MB IDE |
| 445 | running Linux kernel version 1.0.9 from the LST 1.8 Distribution. The kernel |
| 446 | was compiled with gcc.2.5.8. My CD-ROM drive is an Aztech CDA268-01A. My |
| 447 | drive says, that it has Firmware Version AZT26801A1.3. It came with an ISA-bus |
| 448 | interface card and works with polled I/O without DMA and without interrupts. |
| 449 | The code for all other drives was 'remote' tested and debugged by a number of |
| 450 | volunteers on the Internet. |
| 451 | |
| 452 | Points, where I feel that possible problems might be and all points where I |
| 453 | did not completely understand the drive's behaviour or trust my own code are |
| 454 | marked with /*???*/ in the source code. There are also some parts in the |
| 455 | Mitsumi driver, where I did not completely understand their code. |
| 456 | |
| 457 | |
| 458 | 10. ACKNOWLEDGMENTS |
| 459 | Without the help of P.Bush, Aztech, who delivered technical information |
| 460 | about the Aztech Drive and without the help of E.Moenkeberg, GWDG, who did a |
| 461 | great job in analyzing the command structure of various CD-ROM drives, this |
| 462 | work would not have been possible. E.Moenkeberg was also a great help in |
| 463 | making the software 'kernel ready' and in answering many of the CDROM-related |
| 464 | questions in the newsgroups. He really is *the* Linux CD-ROM guru. Thanks |
| 465 | also to all the guys on the Internet, who collected valuable technical |
| 466 | information about CDROMs. |
| 467 | |
| 468 | Joe Nardone (joe@access.digex.net) was a patient tester even for my first |
| 469 | trial, which was more than slow, and made suggestions for code improvement. |
| 470 | Especially the 'finite state machine' azt_poll() was rewritten by Joe to get |
| 471 | clean C code and avoid the ugly 'gotos', which I copied from mcd.c. |
| 472 | |
| 473 | Robby Schirmer (schirmer@fmi.uni-passau.de) tested the audio stuff (ioctls) |
| 474 | and suggested a lot of patches for them. |
| 475 | |
| 476 | Joseph Piskor and Peter Nugent were the first users with the ORCHID CD3110 |
| 477 | and also were very patient with the problems which occurred. |
| 478 | |
| 479 | Reinhard Max delivered the information for the CDROM-interface of the |
| 480 | SoundWave32 soundcards. |
| 481 | |
| 482 | Jochen Kunz and Olaf Kaluza delivered the information for supporting Conrad's |
| 483 | TXC drive. |
| 484 | |
| 485 | Hilmar Berger delivered the patches for supporting CyCDROM CR520ie. |
| 486 | |
| 487 | Anybody, who is interested in these items should have a look at 'ftp.gwdg.de', |
| 488 | directory 'pub/linux/cdrom' and at 'ftp.cdrom.com', directory 'pub/cdrom'. |
| 489 | |
| 490 | 11. PROGRAMMING ADD ONs: cdplay.c |
| 491 | You can use the ioctl-functions included in aztcd.c in your own programs. As |
| 492 | an example on how to do this, you will find a tiny CD Player for audio CDs |
| 493 | named 'cdplay.c'. It allows you to play audio CDs. You can play a specified |
| 494 | track, pause and resume or skip tracks forward and backwards. If you quit the |
| 495 | program without stopping the drive, playing is continued. You can also |
| 496 | (mis)use cdplay to read and hexdump data disks. You can find the code in the |
| 497 | APPENDIX of this file, which you should cut out with an editor and store in a |
| 498 | separate file 'cdplay.c'. To compile it and make it executable, do |
| 499 | gcc -s -Wall -O2 -L/usr/lib cdplay.c -o /usr/local/bin/cdplay # compiles it |
| 500 | chmod +755 /usr/local/bin/cdplay # makes it executable |
| 501 | ln -s /dev/aztcd0 /dev/cdrom # creates a link |
| 502 | (for /usr/lib substitute the top level directory, where your include files |
| 503 | reside, and for /usr/local/bin the directory, where you want the executable |
| 504 | binary to reside ) |
| 505 | |
| 506 | You have to set the correct permissions for cdplay *and* for /dev/mcd0 or |
| 507 | /dev/aztcd0 in order to use it. Remember, that you should not have /dev/cdrom |
| 508 | mounted, when you're playing audio CDs. |
| 509 | |
| 510 | This program is just a hack for testing the ioctl-functions in aztcd.c. I will |
| 511 | not maintain it, so if you run into problems, discard it or have a look into |
| 512 | the source code 'cdplay.c'. The program does only contain a minimum of user |
| 513 | protection and input error detection. If you use the commands in the wrong |
| 514 | order or if you try to read a CD at wrong addresses, you may get error messages |
| 515 | or even hang your machine. If you get STEN_LOW, STEN_LOW_WAIT or segment violation |
| 516 | error messages when using cdplay, after that, the system might not be stable |
| 517 | any more, so you'd better reboot. As the ioctl-functions run in kernel mode, |
| 518 | most normal Linux-multitasking protection features do not work. By using |
| 519 | uninitialized 'wild' pointers etc., it is easy to write to other users' data |
| 520 | and program areas, destroy kernel tables etc.. So if you experiment with ioctls |
| 521 | as always when you are doing systems programming and kernel hacking, you |
| 522 | should have a backup copy of your system in a safe place (and you also |
| 523 | should try restoring from a backup copy first)! |
| 524 | |
| 525 | A reworked and improved version called 'cdtester.c', which has yet more |
| 526 | features for testing CDROM-drives can be found in |
| 527 | Documentation/cdrom/sbpcd, written by E.Moenkeberg. |
| 528 | |
| 529 | Werner Zimmermann |
| 530 | Fachhochschule fuer Technik Esslingen |
| 531 | (EMail: Werner.Zimmermann@fht-esslingen.de) |
| 532 | October, 1997 |
| 533 | |
| 534 | --------------------------------------------------------------------------- |
| 535 | APPENDIX: Source code of cdplay.c |
| 536 | |
| 537 | /* Tiny Audio CD Player |
| 538 | |
| 539 | Copyright 1994, 1995, 1996 Werner Zimmermann (Werner.Zimmermann@fht-esslingen.de) |
| 540 | |
| 541 | This program originally was written to test the audio functions of the |
| 542 | AZTECH.CDROM-driver, but it should work with every CD-ROM drive. Before |
| 543 | using it, you should set a symlink from /dev/cdrom to your real CDROM |
| 544 | device. |
| 545 | |
| 546 | The GNU General Public License applies to this program. |
| 547 | |
| 548 | History: V0.1 W.Zimmermann: First release. Nov. 8, 1994 |
| 549 | V0.2 W.Zimmermann: Enhanced functionality. Nov. 9, 1994 |
| 550 | V0.3 W.Zimmermann: Additional functions. Nov. 28, 1994 |
| 551 | V0.4 W.Zimmermann: fixed some bugs. Dec. 17, 1994 |
| 552 | V0.5 W.Zimmermann: clean 'scanf' commands without compiler warnings |
| 553 | Jan. 6, 1995 |
| 554 | V0.6 W.Zimmermann: volume control (still experimental). Jan. 24, 1995 |
| 555 | V0.7 W.Zimmermann: read raw modified. July 26, 95 |
| 556 | */ |
| 557 | |
| 558 | #include <stdio.h> |
| 559 | #include <ctype.h> |
| 560 | #include <sys/ioctl.h> |
| 561 | #include <sys/types.h> |
| 562 | #include <fcntl.h> |
| 563 | #include <unistd.h> |
| 564 | #include <linux/cdrom.h> |
| 565 | #include <linux/../../drivers/cdrom/aztcd.h> |
| 566 | |
| 567 | void help(void) |
| 568 | { printf("Available Commands: STOP s EJECT/CLOSE e QUIT q\n"); |
| 569 | printf(" PLAY TRACK t PAUSE p RESUME r\n"); |
| 570 | printf(" NEXT TRACK n REPEAT LAST l HELP h\n"); |
| 571 | printf(" SUB CHANNEL c TRACK INFO i PLAY AT a\n"); |
| 572 | printf(" READ d READ RAW w VOLUME v\n"); |
| 573 | } |
| 574 | |
| 575 | int main(void) |
| 576 | { int handle; |
| 577 | unsigned char command=' ', ini=0, first=1, last=1; |
| 578 | unsigned int cmd, i,j,k, arg1,arg2,arg3; |
| 579 | struct cdrom_ti ti; |
| 580 | struct cdrom_tochdr tocHdr; |
| 581 | struct cdrom_subchnl subchnl; |
| 582 | struct cdrom_tocentry entry; |
| 583 | struct cdrom_msf msf; |
| 584 | union { struct cdrom_msf msf; |
| 585 | unsigned char buf[CD_FRAMESIZE_RAW]; |
| 586 | } azt; |
| 587 | struct cdrom_volctrl volctrl; |
| 588 | |
| 589 | printf("\nMini-Audio CD-Player V0.72 (C) 1994,1995,1996 W.Zimmermann\n"); |
| 590 | handle=open("/dev/cdrom",O_RDWR); |
| 591 | ioctl(handle,CDROMRESUME); |
| 592 | |
| 593 | if (handle<=0) |
| 594 | { printf("Drive Error: already playing, no audio disk, door open\n"); |
| 595 | printf(" or no permission (you must be ROOT in order to use this program)\n"); |
| 596 | } |
| 597 | else |
| 598 | { help(); |
| 599 | while (1) |
| 600 | { printf("Type command (h = help): "); |
| 601 | scanf("%s",&command); |
| 602 | switch (command) |
| 603 | { case 'e': cmd=CDROMEJECT; |
| 604 | ioctl(handle,cmd); |
| 605 | break; |
| 606 | case 'p': if (!ini) |
| 607 | { printf("Command not allowed - play track first\n"); |
| 608 | } |
| 609 | else |
| 610 | { cmd=CDROMPAUSE; |
| 611 | if (ioctl(handle,cmd)) printf("Drive Error\n"); |
| 612 | } |
| 613 | break; |
| 614 | case 'r': if (!ini) |
| 615 | { printf("Command not allowed - play track first\n"); |
| 616 | } |
| 617 | else |
| 618 | { cmd=CDROMRESUME; |
| 619 | if (ioctl(handle,cmd)) printf("Drive Error\n"); |
| 620 | } |
| 621 | break; |
| 622 | case 's': cmd=CDROMPAUSE; |
| 623 | if (ioctl(handle,cmd)) printf("Drive error or already stopped\n"); |
| 624 | cmd=CDROMSTOP; |
| 625 | if (ioctl(handle,cmd)) printf("Drive error\n"); |
| 626 | break; |
| 627 | case 't': cmd=CDROMREADTOCHDR; |
| 628 | if (ioctl(handle,cmd,&tocHdr)) printf("Drive Error\n"); |
| 629 | first=tocHdr.cdth_trk0; |
| 630 | last= tocHdr.cdth_trk1; |
| 631 | if ((first==0)||(first>last)) |
| 632 | { printf ("--could not read TOC\n"); |
| 633 | } |
| 634 | else |
| 635 | { printf("--first track: %d --last track: %d --enter track number: ",first,last); |
| 636 | cmd=CDROMPLAYTRKIND; |
| 637 | scanf("%i",&arg1); |
| 638 | ti.cdti_trk0=arg1; |
| 639 | if (ti.cdti_trk0<first) ti.cdti_trk0=first; |
| 640 | if (ti.cdti_trk0>last) ti.cdti_trk0=last; |
| 641 | ti.cdti_ind0=0; |
| 642 | ti.cdti_trk1=last; |
| 643 | ti.cdti_ind1=0; |
| 644 | if (ioctl(handle,cmd,&ti)) printf("Drive Error\n"); |
| 645 | ini=1; |
| 646 | } |
| 647 | break; |
| 648 | case 'n': if (!ini++) |
| 649 | { if (ioctl(handle,CDROMREADTOCHDR,&tocHdr)) printf("Drive Error\n"); |
| 650 | first=tocHdr.cdth_trk0; |
| 651 | last= tocHdr.cdth_trk1; |
| 652 | ti.cdti_trk0=first-1; |
| 653 | } |
| 654 | if ((first==0)||(first>last)) |
| 655 | { printf ("--could not read TOC\n"); |
| 656 | } |
| 657 | else |
| 658 | { cmd=CDROMPLAYTRKIND; |
| 659 | if (++ti.cdti_trk0 > last) ti.cdti_trk0=last; |
| 660 | ti.cdti_ind0=0; |
| 661 | ti.cdti_trk1=last; |
| 662 | ti.cdti_ind1=0; |
| 663 | if (ioctl(handle,cmd,&ti)) printf("Drive Error\n"); |
| 664 | ini=1; |
| 665 | } |
| 666 | break; |
| 667 | case 'l': if (!ini++) |
| 668 | { if (ioctl(handle,CDROMREADTOCHDR,&tocHdr)) printf("Drive Error\n"); |
| 669 | first=tocHdr.cdth_trk0; |
| 670 | last= tocHdr.cdth_trk1; |
| 671 | ti.cdti_trk0=first+1; |
| 672 | } |
| 673 | if ((first==0)||(first>last)) |
| 674 | { printf ("--could not read TOC\n"); |
| 675 | } |
| 676 | else |
| 677 | { cmd=CDROMPLAYTRKIND; |
| 678 | if (--ti.cdti_trk0 < first) ti.cdti_trk0=first; |
| 679 | ti.cdti_ind0=0; |
| 680 | ti.cdti_trk1=last; |
| 681 | ti.cdti_ind1=0; |
| 682 | if (ioctl(handle,cmd,&ti)) printf("Drive Error\n"); |
| 683 | ini=1; |
| 684 | } |
| 685 | break; |
| 686 | case 'c': subchnl.cdsc_format=CDROM_MSF; |
| 687 | if (ioctl(handle,CDROMSUBCHNL,&subchnl)) |
| 688 | printf("Drive Error\n"); |
| 689 | else |
| 690 | { printf("AudioStatus:%s Track:%d Mode:%d MSF=%d:%d:%d\n", \ |
| 691 | subchnl.cdsc_audiostatus==CDROM_AUDIO_PLAY ? "PLAYING":"NOT PLAYING",\ |
| 692 | subchnl.cdsc_trk,subchnl.cdsc_adr, \ |
| 693 | subchnl.cdsc_absaddr.msf.minute, subchnl.cdsc_absaddr.msf.second, \ |
| 694 | subchnl.cdsc_absaddr.msf.frame); |
| 695 | } |
| 696 | break; |
| 697 | case 'i': if (!ini) |
| 698 | { printf("Command not allowed - play track first\n"); |
| 699 | } |
| 700 | else |
| 701 | { cmd=CDROMREADTOCENTRY; |
| 702 | printf("Track No.: "); |
| 703 | scanf("%d",&arg1); |
| 704 | entry.cdte_track=arg1; |
| 705 | if (entry.cdte_track<first) entry.cdte_track=first; |
| 706 | if (entry.cdte_track>last) entry.cdte_track=last; |
| 707 | entry.cdte_format=CDROM_MSF; |
| 708 | if (ioctl(handle,cmd,&entry)) |
| 709 | { printf("Drive error or invalid track no.\n"); |
| 710 | } |
| 711 | else |
| 712 | { printf("Mode %d Track, starts at %d:%d:%d\n", \ |
| 713 | entry.cdte_adr,entry.cdte_addr.msf.minute, \ |
| 714 | entry.cdte_addr.msf.second,entry.cdte_addr.msf.frame); |
| 715 | } |
| 716 | } |
| 717 | break; |
| 718 | case 'a': cmd=CDROMPLAYMSF; |
| 719 | printf("Address (min:sec:frame) "); |
| 720 | scanf("%d:%d:%d",&arg1,&arg2,&arg3); |
| 721 | msf.cdmsf_min0 =arg1; |
| 722 | msf.cdmsf_sec0 =arg2; |
| 723 | msf.cdmsf_frame0=arg3; |
| 724 | if (msf.cdmsf_sec0 > 59) msf.cdmsf_sec0 =59; |
| 725 | if (msf.cdmsf_frame0> 74) msf.cdmsf_frame0=74; |
| 726 | msf.cdmsf_min1=60; |
| 727 | msf.cdmsf_sec1=00; |
| 728 | msf.cdmsf_frame1=00; |
| 729 | if (ioctl(handle,cmd,&msf)) |
| 730 | { printf("Drive error or invalid address\n"); |
| 731 | } |
| 732 | break; |
| 733 | #ifdef AZT_PRIVATE_IOCTLS /*not supported by every CDROM driver*/ |
| 734 | case 'd': cmd=CDROMREADCOOKED; |
| 735 | printf("Address (min:sec:frame) "); |
| 736 | scanf("%d:%d:%d",&arg1,&arg2,&arg3); |
| 737 | azt.msf.cdmsf_min0 =arg1; |
| 738 | azt.msf.cdmsf_sec0 =arg2; |
| 739 | azt.msf.cdmsf_frame0=arg3; |
| 740 | if (azt.msf.cdmsf_sec0 > 59) azt.msf.cdmsf_sec0 =59; |
| 741 | if (azt.msf.cdmsf_frame0> 74) azt.msf.cdmsf_frame0=74; |
| 742 | if (ioctl(handle,cmd,&azt.msf)) |
| 743 | { printf("Drive error, invalid address or unsupported command\n"); |
| 744 | } |
| 745 | k=0; |
| 746 | getchar(); |
| 747 | for (i=0;i<128;i++) |
| 748 | { printf("%4d:",i*16); |
| 749 | for (j=0;j<16;j++) |
| 750 | { printf("%2x ",azt.buf[i*16+j]); |
| 751 | } |
| 752 | for (j=0;j<16;j++) |
| 753 | { if (isalnum(azt.buf[i*16+j])) |
| 754 | printf("%c",azt.buf[i*16+j]); |
| 755 | else |
| 756 | printf("."); |
| 757 | } |
| 758 | printf("\n"); |
| 759 | k++; |
| 760 | if (k>=20) |
| 761 | { printf("press ENTER to continue\n"); |
| 762 | getchar(); |
| 763 | k=0; |
| 764 | } |
| 765 | } |
| 766 | break; |
| 767 | case 'w': cmd=CDROMREADRAW; |
| 768 | printf("Address (min:sec:frame) "); |
| 769 | scanf("%d:%d:%d",&arg1,&arg2,&arg3); |
| 770 | azt.msf.cdmsf_min0 =arg1; |
| 771 | azt.msf.cdmsf_sec0 =arg2; |
| 772 | azt.msf.cdmsf_frame0=arg3; |
| 773 | if (azt.msf.cdmsf_sec0 > 59) azt.msf.cdmsf_sec0 =59; |
| 774 | if (azt.msf.cdmsf_frame0> 74) azt.msf.cdmsf_frame0=74; |
| 775 | if (ioctl(handle,cmd,&azt)) |
| 776 | { printf("Drive error, invalid address or unsupported command\n"); |
| 777 | } |
| 778 | k=0; |
| 779 | for (i=0;i<147;i++) |
| 780 | { printf("%4d:",i*16); |
| 781 | for (j=0;j<16;j++) |
| 782 | { printf("%2x ",azt.buf[i*16+j]); |
| 783 | } |
| 784 | for (j=0;j<16;j++) |
| 785 | { if (isalnum(azt.buf[i*16+j])) |
| 786 | printf("%c",azt.buf[i*16+j]); |
| 787 | else |
| 788 | printf("."); |
| 789 | } |
| 790 | printf("\n"); |
| 791 | k++; |
| 792 | if (k>=20) |
| 793 | { getchar(); |
| 794 | k=0; |
| 795 | } |
| 796 | } |
| 797 | break; |
| 798 | #endif |
| 799 | case 'v': cmd=CDROMVOLCTRL; |
| 800 | printf("--Channel 0 Left (0-255): "); |
| 801 | scanf("%d",&arg1); |
| 802 | printf("--Channel 1 Right (0-255): "); |
| 803 | scanf("%d",&arg2); |
| 804 | volctrl.channel0=arg1; |
| 805 | volctrl.channel1=arg2; |
| 806 | volctrl.channel2=0; |
| 807 | volctrl.channel3=0; |
| 808 | if (ioctl(handle,cmd,&volctrl)) |
| 809 | { printf("Drive error or unsupported command\n"); |
| 810 | } |
| 811 | break; |
| 812 | case 'q': if (close(handle)) printf("Drive Error: CLOSE\n"); |
| 813 | exit(0); |
| 814 | case 'h': help(); |
| 815 | break; |
| 816 | default: printf("unknown command\n"); |
| 817 | break; |
| 818 | } |
| 819 | } |
| 820 | } |
| 821 | return 0; |
| 822 | } |