[alsa-devel] via_dmapos_patch

David Henningsson david.henningsson at canonical.com
Thu Sep 30 10:39:30 CEST 2010

On 2010-09-30 08:58, Takashi Iwai wrote:
> At Wed, 29 Sep 2010 10:14:49 +0200,
> David Henningsson wrote:
>> I'm researching a few bugs where the user claims position_fix=1 helps
>> the problem, but adding the quirk for that model surprisingly didn't. So
>> looking at the code, I concluded that the difference was
>> via_dmapos_patch, and that they all had via_dmapos_patch=1, and that
>> via_dmapos_patch=0 helped them solve the problem. Three out of five (not
>> all of them have reported back on via_dmapos_patch=0 yet) are VIA
>> controllers rev 10.
>> So we now have VIA controllers that need via_dmapos_patch=0.

I'm cc:ing Joseph here. You were the one writing via_dmapos_patch 
originally, could you confirm the suspicion that VIA controller rev 10 
(and possibly more) actually should have via_dmapos_patch turned off?

>> I can think of a few approaches here:
>> 1) since position_fix=1 implicitly sets via_dmapos_patch to 0 (maybe
>> unintentionally), we should add a position_fix=3 meaning lpib +
>> via_dmapos_patch=1
>> 2) figure if something has changed recently (as in "within the last
>> year"...) that has made via_dmapos_patch=1 work worse than before
>> 3) figure out if there are several ATI/VIA controllers that actually
>> never wants the patch.
>> Any thoughts?
> All sound as reasonable proposals.
> The 1 is easy.  David, could you care to send a patch?'

Something like this (untested)?

> 2 and 3 aren't trivial, but we can start by disabling via_dmapos
> for recent revisions.Since it can be controlled over a module
> option by the fix 1, it'll be easier to check the regression.

David Henningsson, Canonical Ltd.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-ALSA-HDA-Add-position_fix-3-module-option-and-refact.patch
Type: text/x-patch
Size: 0 bytes
Desc: not available
Url : http://mailman.alsa-project.org/pipermail/alsa-devel/attachments/20100930/eb76231b/attachment.patch 

More information about the Alsa-devel mailing list