[alsa-devel] [RFC PATCH 0/6] ALSA/HDA: abort probe when DMICs are detected

[Hui Wang]

On 2019/5/25 上午9:40, Hui Wang wrote:
>
> On 2019/5/25 上午12:12, Pierre-Louis Bossart wrote:
>>
>>
>> On 5/24/19 10:45 AM, Daniel Drake wrote:
>>> Thanks for the patches!
>>>
>>> On Fri, May 24, 2019 at 7:26 AM Pierre-Louis Bossart
>>> <pierre-louis.bossart at linux.intel.com> wrote:
>>>> I am not sure if it's a good idea to enable this by default, the
>>>> experience of the first round showed it's risky to make assumptions on
>>>> what BIOS vendors implemented.
>>>
>>> Can you clarify what you mean here, are you saying you don't want to
>>> enable this new DMIC hardware support by default?
>>
>> No. What I am saying is that
>> a) the legacy HDaudio driver does not support DMICs
>> b) the decision to abort the HDaudio legacy driver probe should not 
>> be the default, since it depends on BIOS information that may be 
>> wrong and on which I have *zero* control.
>>
>> There are 4 cases really:
>>
>> 1. DMICs attached to PCH and BIOS/NHLT reports DMICS -> abort HDaudio 
>> legacy probe
>> 2. No DMICs attached to PCH and BIOS/NHLT does not report DMICs -> 
>> continue probe and use HDAudio legacy.
>> 3. DMICs attached to PCH and BIOS/NHLT does not report DMICs -> 
>> broken config, we will need an option to abort the probe by force and 
>> ignore the BIOS if you care about audio capture.
>> 4. no DMICs attached to PCH and BIOS/NHLT reports DMICs -> broken 
>> config, we need an option to ignore the BIOS and continue the probe.
>
> Got it,  we will do a test on a couple of machines, let us see if we 
> can meet 3 and 4 in reality.

I backported these 6 patches to our 5.0 kernel with the sof driver in 
it, and tested on 3 machines which have dmic connected to PCH (audio 
controller pciid 0x9dc8), without these 6 patches, I need to blacklist 
snd_hda_intel.ko and snd_soc_skl.ko to make the sof driver work, after 
backporting these 6 patches, I don't need to blacklist snd_hda_intel.ko, 
but still need to blacklist snd_soc_skl.ko, otherwise the sof driver 
doesn't work.

And I also tested these 6 patches on 3 machines without dmic, I don't 
need to blacklist anything, the audio works well via legacy hdaudio.

So for coexistence  of soc_skl and soc_sof drivers, do we have any plan?

Thanks,

Hui.


>
>>
>> Does this help?
>>