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 at perex.cz> Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.
