[Applied][Raring PATCH] Ubuntu (no-up): ALSA: hda - fixup D3 pin and right channel mute on Haswell HDMI audio

[Tim Gardner]

On 04/12/2013 03:15 AM, David Henningsson wrote:
> On 04/11/2013 09:25 PM, David Henningsson wrote:
>> On 04/11/2013 04:31 PM, Tim Gardner wrote:
>>> On 04/11/2013 07:28 AM, Leann Ogasawara wrote:
>>>> On 04/11/2013 06:09 AM, Leann Ogasawara wrote:
>>>>> Applied to Raring master-next.
>>>>
>>>> Hi David,
>>>>
>>>> After I'd applied this to Raring master-next, there was some concern
>>>> raised about the patch via the #ubuntu-kernel IRC channel.  We are
>>>> hoping to get some clarification and feedback from you.
>>>>
>>>> [06:12:36] <rtg_> ogasawara, actually, I was gonna question David on
>>>> that patch. it seems over engineered to me.
>>>> [06:14:13] <ogasawara> rtg_: I thought it seemed fairly well contained
>>>> and tested
>>>> [06:14:40] <ogasawara> rtg_: it's not too late to yank it if you have
>>>> reservations
>>>> [06:15:12] <rtg_> ogasawara, in that it only affects haswell. however,
>>>> why not just force the D0 and mute settings rather then interrogate the
>>>> HW ? less code I think.
>>>> [06:17:24] <ogasawara> rtg_: it's a valid question, want me to punt it
>>>> till we get clarification?
>>>> [06:18:54] <rtg_> ogasawara, if we can get ahold of him today.
>>>> [06:20:23] <rtg_> ogasawara, by collapsing the code into a more
>>>> definitive form I might worry about audio artifacts such as pops and
>>>> clicks whilst programming those registers. thats really what I'd
>>>> like to
>>>> confirm from him.
>>>>
>>>>>
>>>>> On 04/11/2013 12:38 AM, David Henningsson wrote:
>>>>>> BugLink: https://bugs.launchpad.net/bugs/1167270
>>>>>>
>>>>>> This patch has been tested on two machines, and found to resolve one
>>>>>> of the HDMI audio issues on Haswell.
>>>>>>
>>>>>> The root cause is lack of synchronisation between the video driver
>>>>>> and
>>>>>> the audio driver. Upstream wants to resolve this by adding
>>>>>> synchronisation mechanisms, so they won't take this patch. But since
>>>>>> kernel freeze is today, I wanted to ask you to accept this
>>>>>> intermediate workaround, which at every playback start checks for the
>>>>>> error and corrects it if found.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>> Perhaps something like the attached.
>>>
>>
>> Thanks for the review.
>>
>> There are two things here: The D0 and the mute.
>>
>> For the D0 part, I *think* setting it always is harmless and shouldn't
>> cause any clicks or similar. After all, this is a digital connection so
>> artifacts should be avoided by the recipient (HDMI monitor/receiver)
>> anyway.
>> The gain to keep it as it is would be to avoid the 40 ms delay in case
>> this does not happen (which is does not in the majority of cases). But
>> probably just enabling it, skipping the delay, and not read it back for
>> debugging would work too, I just haven't tested it (and can't do so
>> since the hw is in Asia), and I know you like patches to be tested
>> before you apply them :-)
>>
>> For the mute part; I think the patch suggested by rtg is buggy since it
>> always enables audio, without taking the mute kcontrol into affect:
>> there is a "IEC958 Playback Switch" control that user could set to turn
>> both channels off legitimately. So the mute part needs to stay the way
>> it was in my version of the patch.
> 
> It looks like this patch did not make it into Raring before the kernel
> freeze?
> 
> 

It'll make it into the final upload.

-- 
Tim Gardner tim.gardner at canonical.com