2010/7/6 <peter.ujfalusi@xxxxxxxxx> > Hi, > > ________________________________________ > From: ext Grazvydas Ignotas [notasas@xxxxxxxxx] > Sent: Saturday, July 03, 2010 5:32 PM > To: Mark Brown > Cc: Ujfalusi Peter (Nokia-MS/Tampere); alsa-devel > Subject: Re: issue with TWL4030 > > > On Sat, Jul 3, 2010 at 3:06 AM, Mark Brown > > <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > On Sat, Jul 03, 2010 at 01:50:50AM +0300, Grazvydas Ignotas wrote: > > > > >> there seems to be a problem with TWL4030 hw_param programming, which > >> is easy to reproduce over OSS emulation with this simple program: > > > > > > OSS emulation is strongly disrecommended due to the fact that it > > > repeatedly reprograms things using partially valid configurations. > Some > > > drivers will refuse to run with it. > > > > Well it used to work fine on OMAP+TWL until one of Peter's rework > > patches, I guess 6b87a91f (haven't really bisected), hope we can find > > some solution. We have some closed OSS programs that we can't drop, > > unfortunately. I know userspace OSS emulation solutions exist, but it > > wouldn't hurt to have more options. > > Hmm.. The twl4030->configured meant to protect the reconfiguration of the > codec when the second stream tries to start with different properties than > the already running first (master) stream (and it has been introduced quite > some time ago). > The rest of the hassle around the hw param and parameter locking was to > fix gstreamer's way of starting full duplex operation. > > While I agree with Mark, that OSS emulation should be phased out now (it's > 2010).. > However, extending the state handling might fix your problem, but it > complicates > things greatly, which can lead to more problems... > What I can think of is: > If only one (the master) stream has been opened, and the stream is not > running (the > pcm_trigger has not been called yet), than we could allow reconfiguration > of the codec. > Might work OK, but it might cause some problems under different scenario. > > The OSS emulation call driver's hw_params many time when the OSS program or SDL try to probe the supported rate , format and channels Not easy for the driver to 100% compatible with OSS 3.8 since the default is mono ,U8 and 8000Hz when you use "cat foo.wav > /dev/dsp" or "cat /dev/dsp > foo.wav" _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
