Hi ALSA devs,
(based on a Xilinx ML403, PPC405, OPB bus) I have a custom sound controller, which allows 32bit write accesses to its IO memory, only. The controller supports S16_LE, S16_BE, U16_LE, U16_BE with min. and max. 2 channels (stereo), only! => So a frame has to be 32bits wide and one frame has to be written at one point of time (= one 32bit bus access).
Now, playing a 16kHz, S16_LE, Mono .wav-file with aplay invokes the conversion framework of the alsa-lib. The following line of code (of pcm_plugin.h) is executed:
conv_xx12_xx12: as_u16(dst) = as_u16c(src);
This is a 16bit access and thus fails with a Bus error/Kernel Oops.
Therefore my question is:
In my driver for the controller, how do I tell ALSA, that it is only allowed to write in 32bit quantities? Is this possible at all? Or do I have to use a special .asoundrc file?
Thanks, Joachim
PS: 16bit, signed/unsigned, LE/BE, stereo (!) .wav files can be played without any problem.