On Tue, Mar 05, 2019 at 01:42:32PM +0900, Takashi Sakamoto wrote: > Hi, > > On Mon, Mar 04, 2019 at 11:59:52AM -0500, Sven Van Asbroeck wrote: > > Negotiation seems to work ok, but bclk_ratio is exposed to > > userspace via snd_pcm_hw_params, which is not acceptable. > > > > Constrain bclk_ratio by: > > - cpu dai capabilities && rules > > - codec dai capabilities && rules > > - minimum bclk_ratio is sample_width * channels > > > > In hw_params_choose(), pick the smallest supported bclk_ratio, > > which should correspond to the most efficient solution. > > > > If cpu and codec dais do not specify or constrain supported > > bclk_ratios, alsa will pick sample_width * channels. > > > > Signed-off-by: Sven Van Asbroeck <TheSven73@xxxxxxxxx> > > --- > > include/sound/pcm.h | 11 +++++++++++ > > include/sound/soc.h | 2 ++ > > include/uapi/sound/asound.h | 5 +++-- > > sound/core/pcm_native.c | 34 +++++++++++++++++++++++++++++++++- > > sound/soc/soc-pcm.c | 8 ++++++++ > > 5 files changed, 57 insertions(+), 3 deletions(-) > > In UAPI of Linux sound subsystem, sample formats are represented > in enumerators prefixed with 'SNDRV_PCM_FORMAT_'. In the enumerators, > sample bits and padding bits are represented: > > S8 S16 S20 S24 S32 S18_3 S20_3 S24_3 > sample-bits: 8 16 20 24 32 18 20 24 (=width) > padding-bits: 0 0 12 8 0 6 12 0 > total bits: 8 16 32 32 32 24 24 24 (=physical_width) > > When indicating a certain bit ratio of BCLK/WS from userspace, > applications use correct combination of the above format (=physical_width) > and the number of samples per audio data frame (=channels). You seem to be conflating the in-memory format with the on-wire format. These are two entirely different things. Your table above clearly shows the in-memory format, not the on-wire format. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
