[Sound-open-firmware] [PATCH] host: Stop dma when pause

[Pan, Xiuli]

On 3/15/2018 13:32, Jie, Yang wrote:
>> -----Original Message-----
>> From: sound-open-firmware-bounces at alsa-project.org [mailto:sound-open-
>> firmware-bounces at alsa-project.org] On Behalf Of Xiuli Pan
>> Sent: Thursday, March 15, 2018 1:20 PM
>> To: sound-open-firmware at alsa-project.org
>> Cc: Pan Xiuli <xiuli.pan at linux.intel.com>; Pan, Xiuli <xiuli.pan at intel.com>
>> Subject: [Sound-open-firmware] [PATCH] host: Stop dma when pause
>>
>> From: Pan Xiuli <xiuli.pan at linux.intel.com>
>>
>> For gw-dma host, we need to stop the dma to make sure status are correct
>> for resume.
> What happen if we don't stop for pause, that is what we do for gpdma on BYT.

We will random fail by the check of dma status in fucntion hda_dma_start
static int hda_dma_start(struct dma *dma, int channel)
{
...
          dgcs = host_dma_reg_read(dma, channel, DGCS);
          if (p->chan[channel].status != COMP_STATE_PREPARE ||
              (dgcs & DGCS_GEN)) {
...
}

The DGCS_GEN may not be in stop status when we resume the PCM.

Thanks
Xiuli

> Thanks,
> ~Keyon
>
>> Signed-off-by: Pan Xiuli <xiuli.pan at linux.intel.com>
>>
>> ---
>> Test with:
>> Mininow max rt5651 and GP-MRB nocodec
>> SOF 1.1-stable: aa09938fd330232b201f5683faf8e32975ffcfac
>> SOF-Tool 1.1-stable: 8d9b8d51f9c60e1c1725e9ccd3da22c0b523d0cf
>> https://github.com/plbossart/sound/tree/topic/sof-v4.14:
>> 84ed2d3ba0220424dd441f3a28ed2fe83967ad3a
>> ---
>> src/audio/host.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/src/audio/host.c b/src/audio/host.c
>> index 287c886..744ca02 100644
>> --- a/src/audio/host.c
>> +++ b/src/audio/host.c
>> @@ -465,6 +465,9 @@ static int host_cmd(struct comp_dev *dev, int cmd, void
>> *data)
>> 		return ret;
>>
>> 	switch (cmd) {
>> +	case COMP_CMD_PAUSE:
>> +		dma_stop(hd->dma, hd->chan);
>> +		break;
>> 	case COMP_CMD_STOP:
>> 		ret = host_stop(dev);
>> 		break;
>> --
>> 2.7.4
>>
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