At Wed, 9 Sep 2009 13:29:02 +0100, Sophie Hamilton wrote: > > On 9/9/09, Takashi Iwai <tiwai@xxxxxxx> wrote: > > It turned out that the hw_params determination is done rather inside > > the alsa-lib beforehand. > > > > Try the patch below. This will give you larger buffer size with > > audacious. (And it will work without the driver changes.) > > > > For any apps that require the old behavior, I added the check of > > $LIBASOUND_COMPAT variable. > > Since this patch is for alsa-lib and not for the kernel, this forced > me to check what version I was currently using, which turned out to be > 1.0.20. (specifically, media-libs/alsa-lib-1.0.20-r1) 1.0.21 hadn't > yet been keyworded on my architecture (x86) as stable. This should work in both version since the relevant code hasn't been change for very long time. > So for my first test, I forced 1.0.21 to install anyway, then made > sure the 2.6.30.5 kernel I was using was unpatched, then rebooted to > test whether the upgrade to 1.0.21 (unpatched) would have made any > difference anyway. It didn't; the sound was the same as it was before. > > Then, I copied the alsa-lib ebuild to a local Gentoo repository and > modified it to apply your patch. (I don't know what tricks Gentoo > might have up its sleeve for components as core as this, so I didn't > feel comfortable taking the raw source. It shouldn't made a > difference, but if you'd prefer me to try, I can see what I can do. I > can't promise that any problems would be necessarily from this, > though.) I compiled and installed the new patched 1.0.21, and > rebooted. > > I can confirm now that Audacious does indeed play correctly where it > didn't before. However, using mplayer with the "-ao openal" switch > still doesn't play correctly - in fact, it sounds the same as before - > so it looks like OpenAL is actually doing things slightly differently > than I thought. :/ Yes, likely. The app like openal is usually more sensible regarding latency, so "safe API" described there wasn't appropriate at all. > As a final test, I removed the patch from alsa-lib and re-patched the > kernel with my patch to change the minimum period size to 64 for > cs46xx, so that I could check whether it would still work with the new > alsa-lib 1.0.21 (rather than the 1.0.20 that I was using before). It > does indeed work, in both Audacious and OpenAL. Or, openal is using OSS? You can see /proc/asound/card0/pcm0p/hw_params whether it's OSS emulation mode or not. In OSS mode, OSS parameters are shown there in addition. > So... I'm not sure what's up with OpenAL in this case. Is there > anything more I can do to help? Thanks, that's enough for now. I pushed the patch to alsa-lib git tree now. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
