[alsa-devel] Realtek ALC889: HDA Intel and kernel 3.0 gives choppy sound

[Takashi Iwai]

At Tue, 26 Jul 2011 23:14:47 +0200,
Colomban Wendling wrote:
> 
> Hi,
> 
> Following a bug report started in Debian BTS, in bug 635362 [1], I was
> asked to post here after testing upstream kernels and reproducing the bug.
> 
> So, here's the problem: my HDA audio chip [2] started to output very
> choppy sound with Linux kernel 3.0, while it worked perfectly well in
> previous versions -- latest two I used being 2.6.38 and 2.6.39 from
> Debian. Please note that simply booting on 2.6.39 works as usual, so
> it's IMHO definitely a driver regression.

Do you have 2.6.39 kernel messages?  I see the warnings in your
dmesg below in 3.0* kernels.  Did you get it with the working kernel
as well?

> [    0.000000] ------------[ cut here ]------------
> [    0.000000] WARNING: at drivers/pci/dmar.c:634 warn_invalid_dmar+0x77/0x85()
> [    0.000000] Hardware name: MS-7636
> [    0.000000] Your BIOS is broken; DMAR reported at address fed93000 returns all ones!
> [    0.000000] BIOS vendor: American Megatrends Inc.; Ver: V1.1; Product Version: 1.0
> [    0.000000] Modules linked in:
> [    0.000000] Pid: 0, comm: swapper Not tainted 3.0.0 #4
> [    0.000000] Call Trace:
> [    0.000000]  [<ffffffff81043359>] ? warn_slowpath_common+0x78/0x8c
> [    0.000000]  [<ffffffff810433bb>] ? warn_slowpath_fmt_taint+0x3d/0x42
> [    0.000000]  [<ffffffff81318a7e>] ? __pte+0x7/0x8
> [    0.000000]  [<ffffffff816b2a2d>] ? __early_set_fixmap+0x89/0x8d
> [    0.000000]  [<ffffffff81318a7e>] ? __pte+0x7/0x8
> [    0.000000]  [<ffffffff816b2a2d>] ? __early_set_fixmap+0x89/0x8d
> [    0.000000]  [<ffffffff81318a7e>] ? __pte+0x7/0x8
> [    0.000000]  [<ffffffff811b72c9>] ? warn_invalid_dmar+0x77/0x85
> [    0.000000]  [<ffffffff816b2e3a>] ? early_iounmap+0xc5/0x114
> [    0.000000]  [<ffffffff816c6f13>] ? check_zero_address+0xb0/0xeb
> [    0.000000]  [<ffffffff81327736>] ? bad_to_user+0x620/0x620
> [    0.000000]  [<ffffffff816c6f5f>] ? detect_intel_iommu+0x11/0xa6
> [    0.000000]  [<ffffffff816a5b29>] ? pci_iommu_alloc+0x3f/0x67
> [    0.000000]  [<ffffffff816b280c>] ? mem_init+0x14/0xe5
> [    0.000000]  [<ffffffff8169f94e>] ? start_kernel+0x1d0/0x3c8
> [    0.000000]  [<ffffffff8169f140>] ? early_idt_handlers+0x140/0x140
> [    0.000000]  [<ffffffff8169f3c4>] ? x86_64_start_kernel+0x104/0x111
> [    0.000000] ---[ end trace a7919e7f17c0a725 ]---


Also, you can replace the files in sound/pci/hda/* from 2.6.39 kernel
tree.  If this fixes the problem, it's a sound driver bug.  If not,
it's anything else, e.g. the problem in more core side, e.g. IOMMU
like above or the timer change, etc.


Takashi