[alsa-devel] [PATCH v1 1/2] ASoC: rsnd: ssi: fix race condition in rsnd_ssi_pointer_update

[Jiada Wang]

Hello Morimoto-san

On 12/07/2017 01:45 AM, Kuninori Morimoto wrote:
> Hi Jiada
>
> Thank you for your patch
>
>> Currently there is race condition between set of byte_pos and wrap
>> it around when new buffer starts. If .pointer is called in-between
>> it will result in inconsistent pointer position be returned
>> from .pointer callback.
>>
>> This patch increments buffer pointer atomically to avoid this issue.
>>
>> Signed-off-by: Jiada Wang<jiada_wang at mentor.com>
>> Reviewed-by: Takashi Sakamoto<takashi.sakamoto at miraclelinux.com>
>> ---
> You using playback with PIO mode ?
> Because this function is no longer used on DMA mode
No, we are using rcar sound in DMA mode,
our original patch resolves the issue in core.c for both PIO & DMA mode.

but with your commit a97a06c ("ASoC: rsnd: cleanup pointer related code"),
DMA mode no longer has the race condition issue,
so I ported our fix patch to only address the issue in PIO mode

Thanks,
Jiada
> Best regards
> ---
> Kuninori Morimoto