Re: ASoC: pxa2xx-i2s

[Brian Rhodes <bgr@acdstar.com>]

Karl Beldan wrote:
> Brian Rhodes wrote:
>   
>> i2s replay is not being enabled properly on occasion on my pxa270 
>> board.  Current code is touching SACR1 in hw_params which I believe is 
>> not correct.  That should be configured in trigger before enabling i2s.  
>> Record is not disabled for playback mode.  Any invalid data in the 
>> transmit fifo causes deadlock and replay is being disabled.
>>
>> I have been able to reproduce it in kernel 2.6.26 as well as Linus' git 
>> tree using speaker-test.  (repeatedly starting and stopping).  I've 
>> verified that this fix prevents (at least) this condition.
>>
>> Please review this patch and let me know if there is anything I have 
>> overlooked.
>>
>> Thanks
>>
>> diff --git a/sound/soc/pxa/pxa2xx-i2s.c b/sound/soc/pxa/pxa2xx-i2s.c
>> index 517991f..6cda7f1 100644
>> --- a/sound/soc/pxa/pxa2xx-i2s.c
>> +++ b/sound/soc/pxa/pxa2xx-i2s.c
>> @@ -211,12 +211,10 @@ static int pxa2xx_i2s_hw_params(struct snd_pcm_substream *substream,
>>  	if (!(SACR0 & SACR0_ENB)) {
>>  
>>  		SACR0 = 0;
>> -		SACR1 = 0;
>>  		if (pxa_i2s.master)
>>  			SACR0 |= SACR0_BCKD;
>>  
>>  		SACR0 |= SACR0_RFTH(14) | SACR0_TFTH(1);
>> -		SACR1 |= pxa_i2s.fmt;
>>  	}
>>  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
>>  		SAIMR |= SAIMR_TFS;
>> @@ -257,6 +255,12 @@ static int pxa2xx_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
>>  
>>  	switch (cmd) {
>>  	case SNDRV_PCM_TRIGGER_START:
>> +		SACR1 = pxa_i2s.fmt | SACR1_DRPL | SACR1_DREC;
>>     
>
> Here you are stopping any ongoing stream - removing SACR1 reset in
> hw_params should be enough.
>
>   
In that case, replay would still be disabled is i2s was shutdown.

Value at address 0x40400004 (0x4001e004): 0x10
Value at address 0x40400000 (0x4001e000): 0xE104

I am using normal i2s mode, so in the original code it is basically 
enabling replay twice in hw_params, then enabling i2s in trigger.  Then 
disabling replay and i2s in shutdown.  I'm trying to understand what the 
real problem is here.  Is something failing that is causing replay to be 
disabled by the i2s controller?  The condition is intermittent.  The 
only difference could be timing, or the data in the transmit FIFO.  When 
it gets in this state I can clear DRPL using devmem2 and it audio will 
start playing.

>> +		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
>> +			SACR1 &= ~SACR1_DRPL;
>> +		} else {
>> +			SACR1 &= ~SACR1_DREC;
>> +		}
>>  		SACR0 |= SACR0_ENB;
>>  		break;
>>  	case SNDRV_PCM_TRIGGER_RESUME:
>>
>>     
>
> If - I can - I will post my changes, unless you are finished by then ;)
>
>