From a103c71fe7164dbd863312906b917e9597735608 Mon Sep 17 00:00:00 2001
From: Daniel Mack <zonque@gmail.com>
Date: Wed, 18 May 2011 11:28:44 +0200
Subject: [PATCH] --- yaml --- r: 248188 b: refs/heads/master c:
 3bc6fbc7439a88969de97d979795ce7847950668 h: refs/heads/master v: v3

---
 [refs]                  |  2 +-
 trunk/sound/usb/clock.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 5a28da9ce5af..f55ef925ec2b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0ef283247a0cf0fd2e8370ee467030292eb3129e
+refs/heads/master: 3bc6fbc7439a88969de97d979795ce7847950668
diff --git a/trunk/sound/usb/clock.c b/trunk/sound/usb/clock.c
index 7754a1034545..075195e8661a 100644
--- a/trunk/sound/usb/clock.c
+++ b/trunk/sound/usb/clock.c
@@ -104,6 +104,15 @@ static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
 	int err;
 	unsigned char data;
 	struct usb_device *dev = chip->dev;
+	struct uac_clock_source_descriptor *cs_desc =
+		snd_usb_find_clock_source(chip->ctrl_intf, source_id);
+
+	if (!cs_desc)
+		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))
+		return 1;
 
 	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
@@ -114,7 +123,7 @@ static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
 	if (err < 0) {
 		snd_printk(KERN_WARNING "%s(): cannot get clock validity for id %d\n",
 			   __func__, source_id);
-		return err;
+		return 0;
 	}
 
 	return !!data;