[alsa-devel] [PATCH v2 0/5] mmp audio support

zhangfei gao zhangfei.gao at gmail.com
Thu Jun 21 05:01:21 CEST 2012

On Thu, Jun 14, 2012 at 12:37 AM, Chris Ball <cjb at laptop.org> wrote:
> Hi Zhangfei,
> On Mon, Jun 11 2012, Zhangfei Gao wrote:
>> v1->v2:
>> modify accroingly with suggestion from Vinod and Mark
>> remove deprecated chan->private and dma.h
>> remove prep_slave_sg
>> remove module_init and move operation to probe
>> misc change
>> v0->v1:
>> dmaengine -> soc-dmaengine.
>> update according to Mark's suggestion
>> These patches provide mmp audio support under alsa via dmaengine
>> Support platfrom pxa688 and pxa910
>> mmp_tdma.c and mmp-pcm.c is shared for pxa688 and pxa910
>> pxa688 (mmp2) use mmp2-sspa.c
>> pxa910 directly use pxa-ssp.c
>> mmp_tdma.c is under dmaengine framework
>> Verified on brownstone (pxa688) and ttc-dkb
> Great, we're looking into adopting this for OLPC XO-1.75 too.
> Could you explain how system suspend/resume should work with this
> patchset?  You don't seem to be adding any suspend/resume handlers.
> Thanks,
> - Chris.


Some confusion about audio suspend.
We use android environment, wake lock is hold preventing system
entering suspend when audio work.
Only entering early-suspend, which close LCD etc.
If this is the case, we may not need consider suspend during audio play back.

If support suspend during audio work, some modification required.
I found SNDRV_PCM_TRIGGER_START/STOP is send in suspend/resume
The result is dmaengine_pcm_prepare_and_submit will be re-called every
Unfortunately we malloc descriptor in prep function, but no function
to free at such case.

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