On Wed, Jul 13, 2011 at 1:27 PM, Takashi Iwai tiwai@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 ?