On Fri, 13.06.08 15:55, Jaroslav Kysela (perex@perex.cz) wrote:
On Fri, 13 Jun 2008, Lennart Poettering wrote:
c) snd_pcm_hw_params_get_buffer_size() - snd_pcm_update_avail() returns the fill level, but only works on mmap.
snd_pcm_update_avail() works (or should work) also for standard r/w ops.
Ok, so it's just the documentation that needs fixing? Quoting: "Using of this function is useless for the standard read/write operations. Use it only for mmap access."
d) The snd_pcm_hw_params_get_fifo_size() was supposed to return the 'difference' between a) and c), but was never actually used for that.
Nope. It's maximum latency added by an extra fifo/queue (it does not depend if it's hw or sw fifo). For variable fifo size, we need to extend API.
Ok, so it's an upper ceiling for the difference between a) and c), right?
Lennart