[alsa-devel] Problem with snd_hda_intel from 05-27-2010 snapshot

VDR User user.vdr at gmail.com
Thu May 27 02:17:05 CEST 2010

> 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 at perex.cz>
	 Tue, 11 May 2010 08:21:46 +0000 (10:21 +0200)
committer	Jaroslav Kysela <perex at perex.cz>
	 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.


Signed-off-by: Jaroslav Kysela <perex at perex.cz>


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