[alsa-devel] ALSA calling pcm_pointer excessively?

[Trent Piepho]

On Thu, May 10, 2012 at 1:00 PM, Jassi Brar <jassisinghbrar at gmail.com> wrote:
> On Thu, May 10, 2012 at 9:36 PM, Russell King - ARM Linux
> <linux at arm.linux.org.uk> wrote:
>>
>> The question is - what would cause ALSA to hammer away at the buffer
>> like that - checking it every 16 or 8 DMA bytes transferred?  I'm also
>> seeing around 75% system CPU time, which really isn't good.
>>
>> The above was captured while aplay was running, with no apparant audio
>> corruption.
>>
>> Any ideas?
>>
> I believe it's because the pcm's write tries to keep the data in ring
> buffer filled
> upto brim and keeps polling the dma position till it keeps reporting
> some progress.

Seems like it should sleep until avail_min frames are empty?