From: Tim Gardner <tim.gardner@canonical.com>
Date: Wed, 9 Apr 2014 17:30:44 +0000 (-0600)
Subject: ALSA: usb-audio: Suppress repetitive debug messages from retire_playback_urb()
X-Git-Tag: v3.14.12~8
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=44591702f7d921c4c8b9973b32015bd1867efe47;p=platform%2Fkernel%2Flinux-stable.git

ALSA: usb-audio: Suppress repetitive debug messages from retire_playback_urb()

commit a5065eb6da55b226661456e6a7435f605df98111 upstream.

BugLink: http://bugs.launchpad.net/bugs/1305133

Malfunctioning or slow devices can cause a flood of dmesg SPAM.

I've ignored checkpatch.pl complaints about the use of printk_ratelimit() in favour
of prior art in sound/usb/pcm.c.

WARNING: Prefer printk_ratelimited or pr_<level>_ratelimited to printk_ratelimit
+	if (printk_ratelimit() &&

Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Eldad Zack <eldad@fogrefinery.com>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index ca3256d..7bfa7a1 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1487,7 +1487,8 @@ static void retire_playback_urb(struct snd_usb_substream *subs,
 	 * The error should be lower than 2ms since the estimate relies
 	 * on two reads of a counter updated every ms.
 	 */
-	if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
+	if (printk_ratelimit() &&
+	    abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
 		snd_printk(KERN_DEBUG "delay: estimated %d, actual %d\n",
 			est_delay, subs->last_delay);