[alsa-devel] [PATCH] ALSA: hda - Force polling mode on CFL for fixing codec communication

Hui Wang hui.wang at canonical.com
Wed Mar 21 14:09:08 CET 2018


On 2018年03月21日 17:48, Takashi Iwai wrote:
> On Wed, 21 Mar 2018 10:39:35 +0100,
> Ughreja, Rakesh A wrote:
>>
>>
>>> -----Original Message-----
>>> From: alsa-devel-bounces at alsa-project.org [mailto:alsa-devel-bounces at alsa-
>>> project.org] On Behalf Of Takashi Iwai
>>> Sent: Wednesday, March 21, 2018 2:45 PM
>>> To: alsa-devel at alsa-project.org
>>> Cc: Hui Wang <hui.wang at canonical.com>
>>> Subject: [alsa-devel] [PATCH] ALSA: hda - Force polling mode on CFL for fixing
>>> codec communication
>>>
>>> We've observed too long probe time with Coffee Lake machines, and the
>>> likely cause is some communication problem between the HD-audio
>>> controller and the codec chips.  While the controller expects an IRQ
>>> wakeup for each codec response, it seems sometimes missing, and it
>>> takes one second for the controller driver to time out and read the
>>> response in the polling mode.
>>>
>> I think I faced similar problem while doing the HDA ASoC work.
>>
>> I don't have any way to reproduce and test this. Can we increase
>> the delay after the link is powered ON. The present delay is 100usec,
>> can we make it 521 uSec ? Possibly the codec is not ready after
>> the link is powered on and so it's not responding.
> I'm afraid that this wouldn't help since the issue appears repeatedly
> at later points.
>
> But still it's worth to try.  Hui, could you investigate?

OK,  I will test it tomorrow.

Regards,
Hui.

>
>
> thanks,
>
> Takashi
>
>> File: hda_intel.c
>>
>> 	/* 4. turn link up: set SPA to 1 and wait CPA to 1 */
>> 	intel_ml_lctl_set_power(chip, 1);
>> 	udelay(100); --> change this to 521.
>>
>> Regards,
>> Rakesh
>>
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