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Date: Thu, 6 Sep 2012 15:17:58 +0200
From: Markus Trippelsdorf <markus@trippelsdorf.de>
To: Takashi Iwai <tiwai@suse.de>
Cc: Daniel Mack <zonque@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Subject: Re: snd-usb: "delay: estimated 0, actual 352"
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On 2012.09.06 at 15:08 +0200, Takashi Iwai wrote:
> At Thu, 6 Sep 2012 11:43:48 +0200,
> Markus Trippelsdorf wrote:
> > 
> > On 2012.09.06 at 10:21 +0200, Takashi Iwai wrote:
> > > At Thu, 06 Sep 2012 09:35:26 +0200,
> > > Takashi Iwai wrote:
> > > 
> > > In short, a patch like below may fix the issue (note: completely
> > > untested!)
> > 
> > No it doesn't, unfortunately...
> 
> OK, I start tracking down the problem a bit more deeply now.
> 
> The issue happens when the first two URBs are passed to
> retire_playback_urb().  These are URBs filled before start_endpoints()
> are set, so they contain actually zero size.  Even though these are
> a sort of dummy packets, the driver still tries to check with the
> queued delay account, and gives bogus errors.
> 
> So, essentially the messages are harmless and nothing to worry too
> much, but surely it doesn't look sexy.
> 
> The patch below should fix the problem.  Please give it a try.

Yes, your patch finally fixes the problem. 
Thank you Takashi-san.

-- 
Markus