[alsa-devel] [PATCH 1/3] add API to allow disabling period interrupts
perex at perex.cz
Mon May 17 18:22:11 CEST 2010
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 Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.
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