[alsa-devel] [PATCH v5 4/4] ASoC: SAMSUNG: Add I2S0 internal dma driver

Jassi Brar jassisinghbrar at gmail.com
Wed Jul 13 16:20:21 CEST 2011

On Wed, Jul 13, 2011 at 1:27 PM, Takashi Iwai <tiwai at suse.de> wrote:

>> An important part missing in Claude's quote is
>> +       .periods_min = 1,
>> +       .periods_max = 2,
>> When the periods_max is only 2, the calculations in ALSA mid-layer
>> seem to always
>> decide on using two equal size periods.
>> I didn't dig in the logic but wasn't able to get any application to
>> configure something
>> like {Period_size = 90% of Buffer_size}  which is actually beneficial for
>> Low-Power-Audio-Mode.
> Even you don't set the integer constraint, right?
Right, I didn't set set the integer constraint in this idma driver.

> Does it happen with aplay with -Dhw?
Yes, I remember testing without plugins.

> In the driver side, there is a define RULES_DEBUG in
> sound/core/pcm_native.c, which will enable debug prints of hw-refines.
> A similar flag is found in alsa-lib/src/pcm/pcm_params.c, too.
I don't have access to the h/w anymore.
Maybe someone from Samsung could dig into it and find something useful ?

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