Re: [gentoo-user] A bug in ALSA?

[Mick]

On Thursday 31 Jan 2013 15:39:35 Yuri K. Shatroff wrote:
> Hello gentoo-users,
>
> I've got a Samsung laptop with Intel HDA sound card (Realtek ALC269VB )
> Yesterday I updated software (it was about a month old; I did a eix-sync
> and emerge -Du @world) and somehow sound disappeared: the kernel module
> (snd-hda-intel) still loads and the devices get detected (the
> aforementioned Realtek codec and HDMI codecs). alsa-mixer also seems to
> function. At least, it shows the sound card and allows to change volume
> levels. (in /sys there are also entries for sound/card0)
> But in KDE, the Kmix complains of the device not working, mpg123 says
> cannot find card 0, etc.
> Before the update, everything worked, the kernel version was 3.7.0. I
> even installed kernels 3.7.4, 3.6.11, with many combinations of
> HDA-related options and module parameters, all in vain, now I installed
> 3.7.4 with ultra-verbose DEBUG enabled for ALSA and that's what I'm
> getting:
>
> === BEGIN /var/log/messages ===
> snd_hda_intel 0000:00:1b.0: irq 43 for MSI/MSI-X
> ALSA sound/pci/hda/hda_intel.c:3150 chipset global capabilities = 0x4401
> ALSA.... (many similar messages)
> input: HDA Intel MID Mic as
> /devices/pci0000:00/0000:00:1b.0/sound/card0/input8
> input: HDA Intel MID Headphone as
> /devices/pci0000:00/0000:00:1b.0/sound/card0/input9
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000005
> IP: [<ffffffff811dd420>] strcmp+0x10/0x30
> PGD 119028067 PUD 119029067 PMD 0
> Oops: 0000 [#1] PREEMPT SMP
> ...(registers dump)...
> Call Trace:
>   [<ffffffffa00473d6>] card_id_ok.part.5+0x46/0x80 [snd]
>   [<ffffffffa00475fb>] snd_card_set_id_no_lock+0xeb/0x150 [snd]
>   [<ffffffffa0047725>] snd_card_register+0xc5/0x290 [snd]
>   [<ffffffffa0138a29>] azx_probe_continue+0xa4/0x159 [snd_hda_intel]
>   [<ffffffffa0138e81>] azx_probe+0xd9/0x116 [snd_hda_intel]
>   [<ffffffff811fb319>] pci_device_probe+0x79/0xb0
>   [<ffffffff8126aa4a>] ? driver_sysfs_add+0x7a/0xb0
>   [<ffffffff8126abdc>] really_probe+0x5c/0x210
>   [<ffffffff8126ae9d>] driver_probe_device+0x1d/0x20
>   [<ffffffff8126af3b>] __driver_attach+0x9b/0xa0
>   [<ffffffff8126aea0>] ? driver_probe_device+0x20/0x20
>   [<ffffffff8126922e>] bus_for_each_dev+0x4e/0x80
>   [<ffffffff8126a859>] driver_attach+0x19/0x20
>   [<ffffffff8126a410>] bus_add_driver+0x180/0x270
>   [<ffffffffa010c000>] ? 0xffffffffa010bfff
>   [<ffffffff8126b455>] driver_register+0x75/0x150
>   [<ffffffffa010c000>] ? 0xffffffffa010bfff
>   [<ffffffff811fa3b3>] __pci_register_driver+0x43/0x50
>   [<ffffffffa010c01e>] azx_driver_init+0x1e/0x1000 [snd_hda_intel]
>   [<ffffffff810001fa>] do_one_initcall+0x3a/0x160
>   [<ffffffff81088bf9>] sys_init_module+0xb9/0x220
>   [<ffffffff813bf392>] system_call_fastpath+0x16/0x1b
> ...
> ---[ end trace d00fdb0cd6665b52 ]---
> === END /var/log/messages ===
>
> As one can see, the line
>
>  > BUG: unable to handle kernel NULL pointer dereference
>
> indicates a bug, doesn't it?
>
> If it is a bug, what should I do?
>
> (I have ~amd64 in keywords, pulseaudio is disabled, alsa enabled in USE
> flags)
>
> Strangely enough, I've got another laptop (a little newer model of
> Samsung), also with Realtek, and there the software update didn't cause
> any problems.
>
> Thanks in advance for any ideas.

Hi Yuri, it looks like a kernel bug that causes a kernel oops.  You can search 
https://bugs.gentoo.org/ to see if anyone else has reported it.

-- 
Regards,
Mick