[alsa-devel] [Linux-kernel] [PATCH v5 2/7] ASoC: tegra: Allow 24bit and 32bit samples

[Ben Dooks]

On 07/01/2020 01:39, Dmitry Osipenko wrote:
> 06.01.2020 22:00, Ben Dooks пишет:
>> On 05/01/2020 10:53, Ben Dooks wrote:
>>>
>>>
>>> On 2020-01-05 01:48, Dmitry Osipenko wrote:
>>>> 05.01.2020 03:04, Ben Dooks пишет:
>>>>> [snip]
>>>>>
>>>>> I've just gone through testing.
>>>>>
>>>>> Some simple data tests show 16 and 32-bits work.
>>>>>
>>>>> The 24 bit case seems to be weird, it looks like the 24-bit expects
>>>>> 24 bit samples in 32 bit words. I can't see any packing options to
>>>>> do 24 bit in 24 bit, so we may have to remove 24 bit sample support
>>>>> (which is a shame)
>>>>>
>>>>> My preference is to remove the 24-bit support and keep the 32 bit in.
>>>>>
>>>>
>>>> Interesting.. Jon, could you please confirm that 24bit format isn't
>>>> usable on T30?
>>>
>>> If there is an option of 24 packed into 32, then I think that would work.
>>>
>>> I can try testing that with raw data on Monday.
>>
>> I need to check some things, I assumed 24 was 24 packed bits, it looks
>> like the default is 24 in 32 bits so we may be ok. However I need to
>> re-write my test case which assumed it was 24bits in 3 bytes (S24_3LE).
>>
>> I'll follow up later,
> 
> Okay, the S24_3LE isn't supported by RT5640 codec in my case. I briefly
> looked through the TRM doc and got impression that AHUB could re-pack
> data stream into something that codec supports, but maybe it's a wrong
> impression.
> _________________________________

I did a quick test with the following:

  sox -n -b 16 -c 2 -r 44100 /tmp/tmp.wav  synth sine 500 vol 0.5
  sox -n -b 24 -c 2 -r 44100 /tmp/tmp.wav  synth sine 500 vol 0.5
  sox -n -b 32 -c 2 -r 44100 /tmp/tmp.wav  synth sine 500 vol 0.5

The 16 and 32 work fine, the 24 is showing a playback output freq
of 440Hz instead of 500Hz... this suggests the clock is off, or there
is something else weird going on...

-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

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