This is a note to let you know that I've just added the patch titled
ALSA: usb-audio: Prevent printk ratelimiting from spamming kernel log while DEBUG not defined
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-usb-audio-prevent-printk-ratelimiting-from-spamming-kernel-log-while-debug-not-defined.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b7a7723513dc89f83d6df13206df55d4dc26e825 Mon Sep 17 00:00:00 2001
From: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
Date: Fri, 2 May 2014 15:09:27 +0200
Subject: ALSA: usb-audio: Prevent printk ratelimiting from spamming kernel log while DEBUG not defined
From: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
commit b7a7723513dc89f83d6df13206df55d4dc26e825 upstream.
This (widely used) construction:
if(printk_ratelimit())
dev_dbg()
Causes the ratelimiting to spam the kernel log with the "callbacks suppressed"
message below, even while the dev_dbg it is supposed to rate limit wouldn't
print anything because DEBUG is not defined for this device.
[ 533.803964] retire_playback_urb: 852 callbacks suppressed
[ 538.807930] retire_playback_urb: 852 callbacks suppressed
[ 543.811897] retire_playback_urb: 852 callbacks suppressed
[ 548.815745] retire_playback_urb: 852 callbacks suppressed
[ 553.819826] retire_playback_urb: 852 callbacks suppressed
So use dev_dbg_ratelimited() instead of this construction.
Signed-off-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/usb/pcm.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1487,9 +1487,9 @@ 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 (printk_ratelimit() &&
- abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
- snd_printk(KERN_DEBUG "delay: estimated %d, actual %d\n",
+ if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
+ dev_dbg_ratelimited(&subs->dev->dev,
+ "delay: estimated %d, actual %d\n",
est_delay, subs->last_delay);
if (!subs->running) {
Patches currently in stable-queue which might be from linux@xxxxxxxxxxxxxx are
queue-3.14/alsa-usb-audio-prevent-printk-ratelimiting-from-spamming-kernel-log-while-debug-not-defined.patch
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