[alsa-devel] [PATCH 10/10] ALSA: usb-audio: UAC2: support read-only freq control
eldad at fogrefinery.com
Tue Apr 2 00:45:33 CEST 2013
On Mon, 1 Apr 2013, Torstein Hegge wrote:
> On Sun, Mar 31, 2013 at 17:52:32 +0200, Eldad Zack wrote:
> > Some clocks might be read-only, e.g., external clocks (see also
> > UAC2 18.104.22.168).
> > In this case, setting the sample frequency will always fail
> > (even if the rate is equal to the current clock rate),
> > therefore do not write, but read the value and compare to the
> > requested rate.
> > If it doesn't match, return -ENXIO since the clock is invalid for
> > this configuration.
> I think could be more readable if it was built on top of . Then it
> could check the target rate against the prev_rate reported by the device
> and return before the sample rate set, something like:
Thanks, I think it's a good idea. I'll wait with this patch until you
get your change to Takashi's tree to save some work for everyone.
> @@ -279,6 +275,20 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
> prev_rate = data | (data << 8) | (data << 16) | (data << 24);
You might also want to convert this into le32_to_cpu, etc. like in
patch #5 of this series -- note that as Clemens said, the type should
should be __le32 (and not u32).
Thanks for pointing out the formatting issues, I'll fix these before
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