Re: [alsa-devel] [PATCH] ASoC: dpcm: don't do hw_param when BE has done hw_param

Nenghua Cao
2014-01-10T11:18:31Z

On 01/10/2014 06:55 PM, Takashi Iwai wrote:
> [Corrected mail addresses of both Mark and Liam]
>
Hi, Takashi:
Thanks for correcting my mistake.
> At Fri, 10 Jan 2014 13:36:35 +0800,
> Nenghua Cao wrote:
>>
>> From: Nenghua Cao <nhcao@marvell.com>
>>
>> It fixes the following case:
>> Two FEs connects the same BE; FE1 & BE path has been opened and hw_paramed.
>> At this momment, FE2 & BE path is being opened and hw_paramed. The BE
>> dai will do hw_param again even if it has done hw_param. It is not
>> reasonable.
>> FE1------------>BE
>> FE2-------------^
>
> What happens if FE2 tries to set up an incompatible hw_params?
> (Through a quick glance, it won't work properly well, too, though...)
>
If FE2 uses an incompatible param, it will make FE1 doesn't work. Maybe
FE2 works well.
If FE2 uses the same param, BE hw_param function will be called twice
(This is the most happening case).
So we can't get benefits from it.
>
> Takashi
>
>>
>> Signed-off-by: Nenghua Cao <nhcao@marvell.com>
>> ---
>> sound/soc/soc-pcm.c | 1 -
>> 1 files changed, 0 insertions(+), 1 deletions(-)
>>
>> diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
>> index 891b9a9..ec07e37 100644
>> --- a/sound/soc/soc-pcm.c
>> +++ b/sound/soc/soc-pcm.c
>> @@ -1339,7 +1339,6 @@ static int dpcm_be_dai_hw_params(struct snd_soc_pcm_runtime *fe, int stream)
>> continue;
>>
>> if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_OPEN) &&
>> - (be->dpcm[stream].state != SND_SOC_DPCM_STATE_HW_PARAMS) &&
>> (be->dpcm[stream].state != SND_SOC_DPCM_STATE_HW_FREE))
>> continue;
>>
>> --
>> 1.7.0.4
>>
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