On Sun, Aug 9, 2009 at 6:48 AM, Mark Brown<broonie@xxxxxxxxxxxxx> wrote: > On Sat, Aug 08, 2009 at 02:44:48PM -0400, Jon Smirl wrote: > >> I think I have this backwards, the ac97 driver can take 8/16/24/32 >> it's the Bestcomm program that doesn't know about anything except 32b. > > Remember, you need to consider the I2S driver as well. > >> #define SND_SOC_STD_AC97_FMTS (SNDRV_PCM_FMTBIT_S16_LE |\ >> SNDRV_PCM_FMTBIT_S32_LE |\ >> SNDRV_PCM_FMTBIT_S32_BE) >> shouldn't this be > >> #define SND_SOC_STD_AC97_FMTS (SNDRV_PCM_FMTBIT_S16 |\ >> SNDRV_PCM_FMTBIT_S32) > >> The first form says the AC97 hardware can take both endians, but it >> doesn't take both endians it takes the endian matching the machine it >> is attached to. > > No, it can take any endianess - the wire format is fixed. The layout of > the data in memory is of little interest to the CODEC. The formats used > will be restricted by the CPU driver, the values there are essentially > functioning as a wildcard match. I agree with you, but I think the second form better indicates the wildcard than the first form. It makes it look like endianess is not a factor. If you had used the second form I wouldn't have had a problem bringing up a powerpc driver. >> Don't the standard AC97 formats also include 8 and 24b? > > They'll include whatever the controller is happy to render down onto the > bus. That's just the ones that people have needed so far. We could add 8/24b now so to make thing easier on the next driver developer. > -- Jon Smirl jonsmirl@xxxxxxxxx _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
