If the audio device is externally clocked and set to a rate that does
not match the external clock, the clock will never be valid and we cannot
set the rate successfully. To fix this, allow a rate change even if
the clock is initially invalid, and validate again after the rate is
changed.
This fixes problems with MOTU UltraLite AVB hardware over USB.
Signed-off-by: Adam Goode <agoode@xxxxxxxxxx>
diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index c79749613fa6..db5e39d67a90 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -513,14 +513,28 @@ static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
bool writeable;
u32 bmControls;
+ /* First, try to find a valid clock. This may trigger
+ * automatic clock selection if the current clock is not
+ * valid.
+ */
clock = snd_usb_clock_find_source(chip, fmt->protocol,
fmt->clock, true);
- if (clock < 0)
- return clock;
+ if (clock < 0) {
+ /* We did not find a valid clock, but that might be
+ * because the current sample rate does not match an
+ * external clock source. Try again without validation
+ * and we will do another validation after setting the
+ * rate.
+ */
+ clock = snd_usb_clock_find_source(chip, fmt->protocol,
+ fmt->clock, false);
+ if (clock < 0)
+ return clock;
+ }
prev_rate = get_sample_rate_v2v3(chip, iface, fmt->altsetting, clock);
if (prev_rate == rate)
- return 0;
+ goto validation;
if (fmt->protocol == UAC_VERSION_3) {
struct uac3_clock_source_descriptor *cs_desc;
@@ -577,6 +591,10 @@ static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
snd_usb_set_interface_quirk(dev);
}
+validation:
+ /* validate clock after rate change */
+ if (!uac_clock_source_is_valid(chip, fmt->protocol, clock))
+ return -ENXIO;
return 0;
}
--
2.17.1
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