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Date: Wed, 10 Jun 2009 21:37:14 +0200
Message-ID: <s5hzlcflw2d.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: David Miller <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: sound skipping regression introduced in 2.6.30-rc8
In-Reply-To: <20090610.112804.193703669.davem@davemloft.net>
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At Wed, 10 Jun 2009 11:28:04 -0700 (PDT),
David Miller wrote:
> 
> 
> This change:
> 
> commit c87d9732004b3f8fd82d729f12ccfb96c0df279e
> Author: Takashi Iwai <tiwai@suse.de>
> Date:   Wed May 27 10:53:33 2009 +0200
> 
>     ALSA: Enable PCM hw_ptr_jiffies check only in xrun_debug mode
>     
>     The PCM hw_ptr jiffies check results sometimes in problems when a
>     hardware doesn't give smooth hw_ptr updates.  So far, au88x0 and some
>     other drivers appear not working due to this strict check.
>     However, this check is a nice debug tool, and the capability should be
>     still kept.
>     
>     Hence, we disable this check now as default unless the user enables it
>     by setting the xrun_debug mode to the specific stream via a proc file.
>     
>     Signed-off-by: Takashi Iwai <tiwai@suse.de>
> 
> causes sound to skip while listing to MP3s using mplayer on
> intel8x0 sound cards.

Could you set CONFIG_SND_PCM_XRUN_DEBUG=y and do
	# echo 1 > /proc/asound/card0/pcm0p/xrun_debug
then check your app?  Does it work better, and get any kernel messages?

Basically it's rather a job of the lowlevel driver (intel8x0) to fix /
filter out the bogus values.

I though we have already some code to correct it in 2.6.30, but it
seems not enough...

Also, it'd be helpful if you can check whether the problem exists in
the current sound git tree (for-linus branch), too.
  git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git for-linus


thanks,

Takashi