Re: [PATCH 2/2] ALSA: hda: support for wallclock timestamps

[Clemens Ladisch <clemens@ladisch.de>]

Pierre-Louis Bossart wrote:
> On 09/28/2012 04:33 AM, Clemens Ladisch wrote:
>> Pierre-Louis Bossart wrote:
>>> @@ -1712,6 +1777,7 @@ static struct snd_pcm_hardware azx_pcm_hw = {
>>>                    /* SNDRV_PCM_INFO_RESUME |*/
>>>                    SNDRV_PCM_INFO_PAUSE |
>>>                    SNDRV_PCM_INFO_SYNC_START |
>>> +                 SNDRV_PCM_INFO_HAS_WALL_CLOCK |
>>
>> ... but not if this device is connected to an S/PDIF input.
>
> Yeah, but I can't figure out what happens here. HDAudio is the clock
> master in all cases

Except for those cases described in section 5.4.3 of the HDA spec.

Finding out whether a device is connected to an S/PDIF input is not easy
and might change dynamically.

It might be easiest to omit HAS_WALL_CLOCK for inputs ...


Regards,
Clemens