[PATCH 3.12 123/170] ALSA: usb-audio: Suppress repetitive debug messages from retire_playback_urb()

[Jiri Slaby]

From: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

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@xxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxx>
Cc: Eldad Zack <eldad@xxxxxxxxxxxxxxx>
Cc: Daniel Mack <zonque@xxxxxxxxx>
Cc: Clemens Ladisch <clemens@xxxxxxxxxx>
Signed-off-by: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 sound/usb/pcm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index b375d58871e7..d59e0c1a3e20 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1491,7 +1491,8 @@ 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);
 
-- 
2.0.0

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