[PATCH 3.10 49/53] ALSA: usb-audio: Suppress repetitive debug messages from retire_playback_urb()

From: Greg Kroah-Hartman
Date: Mon Jul 07 2014 - 19:58:38 EST


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

------------------

From: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>

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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
sound/usb/pcm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1419,7 +1419,8 @@ static void retire_playback_urb(struct s
* 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);



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