On Mon, May 21, 2001 at 01:38:46PM +0200, Michel D�nzer wrote: > Daniel Kobras wrote: > > Is 16bit little-endian sound working for anyone using dmasound_pmac? I've > > tried with various pristine 2.4 kernels as well as benh's latest 2.4.4 an my > > TiBook. (Awacs/Screamer Codec Mfct: 1 Rev 3 it reports.) Big-endian sound > > output works fine. Little-endian sound on the other hand produces only > > garbage, and I very much suspect it's the wrong endianness. /dev/sndstat > > tells me that the soft format is correctly set to little-endian, hard format > > is big-endian though, so I suspect the hw byte swap isn't working correctly. > > I'd really like to know whether this problem is specific to TiBooks, or if > > there's a general bug in the dmasound_pmac driver. > > The latter. > > Recent Apple sound hardware (Pismos and G4s as well AFAIK) can't do the byte > order conversion.
Ah, I see. Thanks for the explanation. > Iain Sandoe put software conversion in the dmasound driver at some point, but > that's arguably a wrong approach. Of course it shouldn't advertise the > ability to play little endian when in fact it can't... In a perfect world, yes. But there are simply too many broken programs out there that rely on AFMT_S16_LE being available without properly checking for it. (And even if they check, few have a suitable fallback.) Most of the programs using the old SNDCTL_DSP_SAMPLESIZE call rather than SNDCTL_DSP_SETFMT belong into this category. They push a value of 16, and rarely realise this implies little-endianness of the data. Stuffing a conversion layer into the driver therefore makes tons of sense, and avoids a pile of legacy problems. Regards, Daniel.
