ALSA: snd-usb: fix clock source validity index

uac_clock_source_is_valid() uses the control selector value to access the bmControls bitmap of the clock source unit. This is wrong, as control selector values start from 1, while the bitmap uses all available bits. In other words, "Clock Validity Control" is stored in D3..2, not D5..4 of the clock selector unit's bmControls. Signed-off-by: Daniel Mack <[email protected]> Reported-by: Andreas Koch <[email protected]> Cc: [email protected] Signed-off-by: Takashi Iwai <[email protected]>
mna · Aug 1, 2012 · aff252a · aff252a
1 parent 1f43f6c
commit aff252a
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/sound/usb/clock.c b/sound/usb/clock.c
@@ -111,7 +111,8 @@ static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
 		return 0;
 
 	/* If a clock source can't tell us whether it's valid, we assume it is */
-	if (!uac2_control_is_readable(cs_desc->bmControls, UAC2_CS_CONTROL_CLOCK_VALID))
+	if (!uac2_control_is_readable(cs_desc->bmControls,
+				      UAC2_CS_CONTROL_CLOCK_VALID - 1))
 		return 1;
 
 	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,