Hi all, I had some luck getting rid of the warnings, but I still get a segmentation fault when loading em28xx-audio - however, now the message is a BUG: unable to handle kernel paging request (output of dmesg when modprobe em28xx-audio: http://pastebin.com/f6513908a ).
I would greatly appreciate any help and guidance to get rid of it. I too believe, like elsewhere said, that this may be a problem with versions of objects / kernels - in that case, I'd be ready to go back to other drivers or objects or kernels, or compile the kernel and ALSA drivers and v4l from scratch, but I really need some guidance on what would be the most viable to do - and in particular, how to read / keep track of current versions of objects and whether they do not match... The procedure I did to get rid of the symbols is outlined below.. Thanks in advance for any comments, Cheers ........................ First of all, I got inspired by http://groups.google.com/group/linux.kernel/msg/d19d43a4f3de4ff1 Author: S.Çağlar Onur <[EMAIL PROTECTED]> Date: Sun Feb 10 05:27:23 2008 +0200 drivers/media/video/em28xx/: Fix undefined symbol error with CONFIG_SND=N Without this you get undefined symbol errors with CONFIG_SND=N: ERROR: "snd_pcm_period_elapsed" [drivers/media/video/em28xx/em28xx-alsa.ko] undefined! --- drivers/media/video/em28xx/Kconfig +++ drivers/media/video/em28xx/Kconfig @@ -13,7 +13,8 @@ module will be called em28xx config VIDEO_EM28XX_ALSA - depends on VIDEO_EM28XX + depends on VIDEO_EM28XX && SND + select SND_PCM tristate "Empia EM28xx ALSA audio module" What this probably says that functions in snd.ko and snd-pcm.ko should somehow be 'linked' to em28xx-alsa, so that the symbols are resolved. I also realised that there are several versions of v4l-dvb, which em28xx is a part of. Turns out, I have used both http://mcentral.de/hg/~mrec/v4l-dvb-kernel and http://linuxtv.org/hg/v4l-dvb (and possibly others). It is that linuxtv.org/hg/v4l-dvb driver (or rather the one I got at http://linuxtv.org/hg/v4l-dvb/archive/tip.tar.gz, which I think is the same), is the one where there is a em28xx-audio source, which compiles to em28xx-alsa.ko. So the above symbol linking problem should apply to em28xx-audio as well? Now, the problem is that I don't know how to use Kconfig ( or kbuild? is that for KDE? I'm on ubuntu 8.04 gnome) which the fix seems to be for; and I don't know how to make dependencies in makefiles. What I found, is that I can sort of simulate linking in makefiles, my editing the /v4l/Module.symvers file that gets generated by the v4l-dvb make process. So, after all those builds and cleanings, last time I compiled linuxtv.org/hg/v4l-dvb, even em28xx itself had symbol problems. So, I tried to start from scratch - clean everything and run: hg clone http://mcentral.de/hg/~mrec/v4l-dvb-kernel cd v4l-dvb-kernel sudo make LINUXINCLUDE="-I`pwd`/linux/include -I`pwd`/v4l -Iinclude -I/usr/src/linux-headers-2.6.24-12-generic/include/linux -include include/linux/autoconf.h" I build all modules (some 199), although I found since, that one can use 'make menuconfig' to select only the needed drivers.. at this make, I get the famous errors: Building modules, stage 2. MODPOST 199 modules WARNING: "snd_pcm_lib_ioctl" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! WARNING: "snd_pcm_period_elapsed" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! WARNING: "snd_pcm_hw_constraint_integer" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! WARNING: "snd_card_register" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! WARNING: "snd_pcm_set_ops" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! WARNING: "snd_pcm_new" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! WARNING: "snd_card_new" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! WARNING: "snd_card_free" [/usr/src/v4l-dvb-kernel/v4l/em28xx-audio.ko] undefined! Now, first I try running modinfo snd modinfo snd-pcm to find the locations of the .ko modules that get loaded by default. I get: filename: /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd.ko filename: /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd-pcm.ko Then I 'dump' the symbol tables of these .ko files: readelf -s /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd.ko > snd.txt readelf -s /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd-pcm.ko > snd-pcm.txt Then, open these text files in gedit, and search for all missing symbols like "snd_pcm_period_elapsed".. One gets at least two finds, say: 121: 000022e0 841 FUNC GLOBAL DEFAULT 2 snd_pcm_period_elapsed 139: f9efe8b0 0 NOTYPE GLOBAL DEFAULT ABS __crc_snd_pcm_period_elapsed It is the hex adress of the __crc_ entry (the one with ABS) that is needed.. Finally, I open /v4l-dvb-kernel/v4l/Module.symvers, and add entries for all missing symbols, like 0x640dad5e snd_pcm_new /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd-pcm EXPORT_SYMBOL 0x55ccbe2a snd_pcm_set_ops /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd-pcm EXPORT_SYMBOL 0x24ff27d0 snd_pcm_lib_ioctl /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd-pcm EXPORT_SYMBOL 0xf9efe8b0 snd_pcm_period_elapsed /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd-pcm EXPORT_SYMBOL 0x53dac402 snd_pcm_hw_constraint_integer /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd-pcm EXPORT_SYMBOL 0x497891bc snd_card_new /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd EXPORT_SYMBOL 0xe594a857 snd_card_register /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd EXPORT_SYMBOL 0xed23649b snd_card_free /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/acore/snd EXPORT_SYMBOL Then save Module.symvers, run make again. em28xx-audio recompiles, no errors are reported. However, then when it is loaded (either by modprobe or by /etc/modules) the above BUG: unable to handle kernel paging request occurs... My latest data: cat /proc/asound/version: Advanced Linux Sound Architecture Driver Version 1.0.16. Compiled on Mar 11 2008 for kernel 2.6.24-12-generic (SMP). uname -a: Linux LJUTFRAER 2.6.24-12-generic #1 SMP Wed Mar 12 23:01:54 UTC 2008 i686 GNU/Linux cat /proc/version: Linux version 2.6.24-12-generic ([EMAIL PROTECTED]) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu4)) #1 SMP Wed Mar 12 23:01:54 UTC 2008 cat /etc/issue: Ubuntu hardy (development branch) _______________________________________________ Em28xx mailing list Em28xx@mcentral.de http://mcentral.de/mailman/listinfo/em28xx
