[alsa-devel] [PATCH] ASoC: amd: Buffer Size instead of MAX Buffer

[vishnu]

On 11/02/20 9:08 PM, Mark Brown wrote:
> On Tue, Feb 11, 2020 at 06:42:28PM +0530, Ravulapati Vishnu vardhan rao wrote:
> 
>> Because of MAX BUFFER size in register,when user/app give small
>> buffer size produces noise of old data in buffer.
>> This patch rectifies this noise when using different
>> buffer sizes less than MAX BUFFER.
> 
> In what way does this patch fix the issue?  I looks like it's moving a
> buffer size setting from DMA to I2S but it's not clear why or how this
> fixes the issue, or indeed what the actual issue that's causing what are
> presumably underruns is?
> 
prior to this fix the value in Tx/Rx Ring Buffer Size register 
ACP_BT_TX_RINGBUFSIZE,ACP_BT_RX_RINGBUFSIZE and same in I2S RINGBUFSIZE 
registers was statically set to maximum which is wrong.
Buffer size must be equal to actual allocated.

Due to which When I play any audio:aplay -Dhw:2,0 test.wav and then stop 
and play  aplay -Dhw:2,0 -c2 -fS16_LE -r48000 /dev/zero 
--buffer-size=2048 I hear some part of old audio.


So after adding above fix the issue is not reproduced.