On Wed, 26 May 2010, VDR User wrote:
Hi. I had been mostly successfully using the snd_hda_intel driver
from the stable kernel 2.6.34 for HDMI audio with my Nvidia GT220
video card. In an attempt to see if any recent changes to
snd_hda_intel would fix a problem I've been having with "pcm_hw.c:
snd_pcm_hw_delay() SNDRV_PCM_IOCTL_DELAY failed" I decided to download
the latest snapshot. Unfortunately with these drivers I have no
audio. All my settings, and everything have remained the same. The
only noticable difference I've found is
/sys/module/snd_hda_intel/parameters/probe_only is 0,0,0,0,0,0,0,0 in
the snapshot drivers, and N,N,N,N,N,N,N,N in the 2.6.34 kernel drivers
(which are compiled into the kernel).
As a followup, I tried each snapshot going backwards from 05-27-2010
to discover where the breakage occured. The last working snapshot is
05-11-2010, it breaks at 05-12-2010. After making a diff of the
sound/pci/hda/ dir, I've discovered that the offending patch is:
author Jaroslav Kysela <perex@xxxxxxxx>
Tue, 11 May 2010 08:21:46 +0000 (10:21 +0200)
committer Jaroslav Kysela <perex@xxxxxxxx>
Tue, 11 May 2010 08:25:50 +0000 (10:25 +0200)
commit 432f57d106e6d5c69fce74c888de32c6df347494
tree 536120322429edb82d672547595d8dba7ac10b5e tree | snapshot
parent 533538fe6243d87b68db6942b1c7a1acb9fe504d commit | diff
[ALSA] snd-hda-intel: use WALLCLK register to check for early irqs
Use 24Mhz WALLCLK register to ignore too early interrupts and
wrong interrupt status. The bad timing confuses the higher ALSA
layer and causes audio skipping. More information about behaviour
and debugging can be found in kernel bz#15912.
https://bugzilla.kernel.org/show_bug.cgi?id=15912
Check any suspicious lines in /var/log/messages and follow proc xrun_debug
settings noted in bug above. I need at least 20 first lines after the
playback is started.
Also, use 'aplay -Dplughw:0' from the alsa-utils package to trigger
the playback.
Jaroslav
-----
Jaroslav Kysela <perex@xxxxxxxx>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.
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