[alsa-devel] [PATCH] ALSA: hda - Use LPIB position fix for Acer AO751h

[Takashi Iwai]

At Thu, 28 Feb 2013 11:05:20 +0100,
David Henningsson wrote:
> 
> On 02/28/2013 10:29 AM, Takashi Iwai wrote:
> > At Thu, 28 Feb 2013 09:49:23 +0100,
> > David Henningsson wrote:
> >>
> >> On 02/28/2013 08:21 AM, Takashi Iwai wrote:
> >>> At Thu, 28 Feb 2013 08:18:30 +0100,
> >>> David Henningsson wrote:
> >>>>
> >>>> The user reports a regression (choppy audio), and that
> >>>> position_fix=1 (or position_fix=4) fixes the issue.
> >>>>
> >>>> This is a Poulsbo controller (8086:811b (rev 07)), so might be
> >>>> worth checking if other Poulsbo machines suffer from the same bug.
> >>>>
> >>>> Cc: stable at vger.kernel.org [v3.7+]
> >>>> BugLink: https://bugs.launchpad.net/bugs/1132562
> >>>> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
> >>>
> >>> Please check whether the latest sound git tree works as is.
> >>> We enabled the LPIB delay counting for Poulsbo there, and it may fix
> >>> most cases.
> >>
> >> The test was done on a 3.8 based kernel. Isn't LPIB delay counting
> >> enabled there as well?
> >
> > No, it was added fairly recently.
> > I didn't put Cc to stable for the commit
> > f748abcc5bf62de007019d841f7caba81cc3d673.  If this is confirmed to
> > work in general for Poulsbo, we can merge to stable.
> >
> > But, overall I wonder why POSFIX_LPIB is needed for this device.
> > In the recent kernels up to 3.8, LPIB is used as default for Poulsbo.
> 
> According to "git describe --contains", this commit was added to 
> v3.8-rc6, and released into Ubuntu before this bug was filed.

Ah, right, I forgot it was included in 3.8-final...

> Probably 
> this commit is was what caused the regression then, and so the cc to 
> stable should be to 3.8+, not 3.7+.

Possible.  We seem have no reliable generic solution for Poulsbo,
unfortunately.

But, POSFIX_LPIB is most likely buggy in the regard of capture.
Can the tester check whether the recording really works, also without
pulseaudio, too?) I guess POSFIX_COMBO would work better for Poulsbo.

(Oh I dropped AZX_DCAPS_POSFIX_COMBO, and we may need to revive in in
 bit 24)

> 
> > Takashi
> >
> >
> > Takashi
> 
> Have you cloned yourself, or is it just a race condition? :-)

It must be a dejavu, aka a bug, due to a lack of caffeine.


Takashi