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

[Ben Dooks]

On 24/01/2020 16:50, Jon Hunter wrote:
> 
> On 23/01/2020 19:38, Ben Dooks wrote:
>> 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...
> 
> I was looking at using sox to create such as file, but the above command
> generates a S24_3LE file and not S24_LE file. The codec on Jetson-TK1
> supports S24_LE but does not support S24_3LE and so I cannot test this.
> Anyway, we really need to test S24_LE and not S24_3LE because this is
> the problem that Dmitry is having.
> 
> Ben is S24_3LE what you really need to support?

No, it is S24_LE the format this hardware supports. I wonder if
aplay is transforming it.

Plug PCM: Linear conversion PCM (S24_LE)
Its setup is:
   stream       : PLAYBACK
   access       : RW_INTERLEAVED
   format       : S24_3LE
   subformat    : STD
   channels     : 2

So I assume aplay has turned the S24_3LE -> S24_LE



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

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