At Mon, 16 Jun 2008 14:29:03 +0200 (CEST), Jaroslav Kysela wrote: > > On Mon, 16 Jun 2008, Takashi Iwai wrote: > > > At Mon, 16 Jun 2008 12:53:11 +0200 (CEST), > > Jaroslav Kysela wrote: > > > > > > On Mon, 16 Jun 2008, Takashi Iwai wrote: > > > > > > > At Fri, 13 Jun 2008 21:13:03 +0200, > > > > Lennart Poettering wrote: > > > > > > > > > > Heya, > > > > > > > > > > the HDA driver allows a playback buffer size of something like 64K > > > > > onyl. Is this a driver limitation or a limitation of the hardware? > > > > > Skimming through the docs I cannot see anything like this, and I got > > > > > the idea that the audio buffer is maintained in system memory, not > > > > > sound card memory, so why this limit? > > > > > > > > This comes from the buffer pre-allocator. > > > > Run the below: > > > > > > > > # echo 1024 > /proc/asound/card0/pcm0p/sub0/prealloc > > > > > > > > then you can use now 1MB buffer. snd-hda-intel has max > > > > pre-allocation buffer size 1MB, and this is the hard-coded limit. > > > > > > > > It's rather a silly constraint, and I think it'd be better cut off. > > > > OTOH, this makes the system safer (e.g. avoiding page allocations for > > > > too large buffers), and there is a proper workaround, too. > > > > So, I'm open about this change, so far. > > > > > > Which workaround you're talking about? > > > > Reset a proc file manually like the above. Without this, you cannot > > allocate the buffer over the pre-allocated size. > > I'm not quite sure what you like to change. Make 1MB limit smaller? Or > change the default preallocated size? Or remove preallocation? I think > that it might make sense to increase the default preallocation value to > 128KB or 192KB. We have some options: A. Remove the sucking hw_constraint for the pre-allocated size B. Remove/improve the whole pre-allocation mechanism C. Increase the default pre-allocation size of snd-hda-intel D. Ignore complains I'm for, but still open about A. B would be a good option if we can (have time and resource). C would be ad hoc but surely work for this particular case. D is the current status. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
