Commit b7a77235 authored May 02, 2014 by Sander Eikelenboom Committed by Takashi Iwai May 02, 2014

ALSA: usb-audio: Prevent printk ratelimiting from spamming kernel log while DEBUG not defined



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@eikelenboom.it>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent 91943954

sound/usb/pcm.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -1501,9 +1501,8 @@ 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 (printk_ratelimit() &&
		abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
		dev_dbg(&subs->dev->dev,
		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);

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