On Wed, 2007-05-30 at 10:46 -0500, Timur Tabi wrote: > Liam Girdwood wrote: > > > Fwiw, you should be ok in the mean time as most audio data is stored on > > file in little endian format. Your media player should open such little > > endian files as *_LE when it configures the ALSA pcm. This should work > > if your I2S, DMA and codec are marked as supporting LE formats. > > What about this snippet in asound.h: > > #ifdef __LITTLE_ENDIAN > #define SNDRV_LITTLE_ENDIAN > #else > #ifdef __BIG_ENDIAN > #define SNDRV_BIG_ENDIAN > > ... > > #ifdef SNDRV_LITTLE_ENDIAN > #define SNDRV_PCM_FORMAT_S16 SNDRV_PCM_FORMAT_S16_LE > #define SNDRV_PCM_FORMAT_U16 SNDRV_PCM_FORMAT_U16_LE > #define SNDRV_PCM_FORMAT_S24 SNDRV_PCM_FORMAT_S24_LE > ... > #endif > #ifdef SNDRV_BIG_ENDIAN > #define SNDRV_PCM_FORMAT_S16 SNDRV_PCM_FORMAT_S16_BE > #define SNDRV_PCM_FORMAT_U16 SNDRV_PCM_FORMAT_U16_BE > #define SNDRV_PCM_FORMAT_S24 SNDRV_PCM_FORMAT_S24_BE > ... > #endif > > I could then do this: > > #define CS4270_FORMATS SNDRV_PCM_FMTBIT_S24 I'll fix this in the core so we don't need to do this. Please use _LE atm. > > On big-endian platforms like mine, CS4270_FORMATS will be SNDRV_PCM_FORMAT_S24_BE and on > little-endian platforms it will be SNDRV_PCM_FORMAT_S24_LE. Assuming the I2S registers > are the same endian as the platform, will this work? > I think this probably depends on how your audio FIFO's align the data received from memory/DMA. They should do any bit reordering based on the audio format, and size etc set in the control register. (Although, ymmv.) > If not, then what about this: > > #define CS4270_FORMATS (SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE) > > That would tell ALSA that the CS4270 supports both formats, which isn't technically true, > but it wouldn't matter because the I2S interface is what determines the actual > "endianness" of the serial data. > This looks fine as a workaround atm, I'll try and have a look at this bug tomorrow so we don't need to do this. Liam _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
