On Fri, May 08, 2015 at 04:16:08PM +0300, Jyri Sarha wrote:

On 2015-04-02 12:22, Russell King wrote:

...

+static const unsigned int eld_rates[] = {

• 32000,
• 44100,
• 48000,
• 88200,
• 96000,
• 176400,
• 192000,

+};

For what I can see, you are setting the cross dependency between the sample rate and channels incorrectly.

There is a dependency between sample rate and channels.

You should look for the currently tested channel count directly from hw params.

I'm not so sure that's right after looking at snd_ac97_pcm_double_rate_rules(). That's pretty much the same problem - AC'97 codecs can operate at a sample rate of either the bus frame frequency or twice the bus frame frequency.

They achieve twice the bus frame frequency by reallocating a couple of the PCM data slots which would otherwise be used for >2 channels to the first two channels, thus allowing two front channel samples per frame.

AC'97 limits the number of channels to two if:

if (rate->min > 48000) {

and limits the sample rate to 1-48kHz if:

if (channels->min > 2) {

From this side the dependency is missing all together.

Yes, it I initially couldn't work out how to do that bit... but I have a solution now which seems to sort-of work.

Testing with aplay, I find that it seems to mostly work, and I guess that:

aplay -D hw:0,0 -v -f S24_LE -c 6 -r 192000 /dev/zero

resulting in:

Playing raw data '/dev/zero' : Signed 24 bit Little Endian, Rate 192000 Hz, Channels 6 Warning: rate is not accurate (requested = 192000Hz, got = 48000Hz) please, try the plug plugin Hardware PCM card 0 'DW-HDMI' device 0 subdevice 0 Its setup is: stream : PLAYBACK access : RW_INTERLEAVED format : S24_LE subformat : STD channels : 6 rate : 48000 exact rate : 48000 (48000/1)

is acceptable.

Also looking at AC'97, I don't need to list the same parameter as a dependent of the rule... something I'll try when I'm back from the hospital later this afternoon...