On Mon, 17 May 2010, pl bossart wrote:
2) The avail_min parameter in sw_params was overlooked. The lowlevel
drivers can use this value to compute the wake-up point and set hw
appropriately, to do wake-up at requested time. We can add a support
functions like "return how many samples are expected to be transferred
for next wake-up point" to linux/sound/pcm.h. In case when this value
is high, no interrupts (wake ups) will be processed in the driver. If
hardware cannot do the precise transfers, we can program a system
timer as the wake-up source.
Isn't the interrupt-related behavior defined when you setup the DMA
linked list. i.e when hw_params are frozen? The problem with sw_params
is that they can change at any time, and the hardware may not support
this. I have no idea how you would modify the HDAudio controller
behavior dynamically for example.
Look my last sentence - we should use another timing source like system
timer in this case.
Jaroslav
-----
Jaroslav Kysela <perex@xxxxxxxx>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.
_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
