At Mon, 30 Aug 2010 10:11:09 -0700, Stephen Warren wrote: > > It looks like even though some NVIDIA MCPs have min/max channel of 2/8, not > all HW supports the intermediate # channels (4 and 6) over HDMI. Various > combinations are supported on various HW: 2, 2/8, 2/6/8, 2/4/6/8. > > At present, when an application uses an unsupported number of channels, > playback appears to operate correctly, but the HW doesn't actually send the > audio data over HDMI. > > Is it possible for patch_nvhdmi.c to simply program codec the HW in 8-channel > mode even though the controller is only sending 4-/6-channel data? I'm not sure whether HD-audio codec can have a /dev/zero-kind of stream. It's possible to set up but I don't think it's worth. It'd be far easier to omit 4 and 6-channels for such a case. > I'm not > sure if this would cause the codec to get out of sync with the controller's > data stream. Would the controller end up grabbing 8 channels worth of data > from the stream at a time, have no way to synchronize to the start of each > sample, and hence end up packing e.g. 2 complete 4 channel samples into a > single 8 channel sample? > > If not, it seems that patch_nvhdmi.c should be modified so that each codec's > _open() function returns an error for unsupported rates. I can code that up > if we need. Do you mean for unsupported channels? > Unfortunately, it doesn't look like it's possible for applications to query > this information from ALSA, since a hw_params_t exposes just a min/max > channel count rather than a mask. It can be also masked. Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
