I'm trying to use "my" hardware at a 204800 sample rate. I've changed the DAI and codec limits to match. If I limit them to anything below 192kHz, everything behaves as expected and I can record at up to that rate, also if that rate is not a multiple of 48k or 44k1 (using "SNDRV_PCM_RATE_KNOT" constant).
When I specifiy anything over 192000, I bump onto some ceiling, and I cannot figure out what's causing it. I patched alsa-utils to allow
192000 already (there is a silly check on that in aplay.c which bails
out early without asking the driver).
# arecord -D hw:ADC8 --duration=5 -f S32_LE -c 2 -r 204800 /tmp/recording.wav Recording WAVE '/tmp/recording.wav' : Signed 32 bit Little Endian, Rate 204800 Hz, Stereo Warning: rate is not accurate (requested = 204800Hz, got = 192000Hz) please, try the plug plugin # # arecord -D hw:ADC8 --duration=5 -f S32_LE -c 2 -r 192000 /tmp/recording.wav Recording WAVE '/tmp/recording.wav' : Signed 32 bit Little Endian, Rate 192000 Hz, Stereo #
I also tried a "grep" on the kernel (i'm still on 2.3.7 though) source files on "192000" but found nothing that would limit the sample rate to that. I'm running out of ideas. How can I break this limit? Or where in the kernel can I find the part that calculates the max rate?
Mike.