On Tue, 28 Apr 2009, Takashi Iwai wrote: >> - leave current fifo_size without change (there will be only small FIFO >> values to notify applications about small extra delays before samples >> reaches DAC or leaves ADC) > > fifo_size field is supposed to be constant, and shouldn't be changed > dynamically after open. This is a problem if the FIFO size varies > depending on the parameter. The alsa-lib's documentation states that one configuration must be chosen (thus hw_params should be called) to obtain fifo_size. It might depend on hardware parameters, but is static then. I would not propose to change anything with it. >> - add cache_size value to snd_pcm_hardware struct - here will be >> stored area of buffer which might be cached in the hardware for large >> FIFOs including prepared USB's URBs (the upper layer should not work >> with this buffer area - rewind operation etc.) > > I already submitted a similar patch quite ago. Actually, it exposes > the delay account in snd_pcm_status() delay calculation. The delay > value can be dynamically changed. > > The current test patches are found on sound unstable tree > topic/pcm-delay branch. > git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-unstable-2.6.git Looks good. Could you pick these patches to your stable tree so we can stack other patches on top? I need to add 'delay' to hdelta in current elapsed callback to avoid false alarms. Also, John should initialize this runtime->delay to correct value in frames in the mpc driver. 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
