git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From b7a7723513dc89f83d6df13206df55d4dc26e825 Mon Sep 17 00:00:00 2001
   2 From: Sander Eikelenboom <linux@eikelenboom.it>
   3 Date: Fri, 2 May 2014 15:09:27 +0200
   4 Subject: ALSA: usb-audio: Prevent printk ratelimiting from spamming kernel log while DEBUG not defined
   5
   6 From: Sander Eikelenboom <linux@eikelenboom.it>
   7
   8 commit b7a7723513dc89f83d6df13206df55d4dc26e825 upstream.
   9
  10 This (widely used) construction:
  11
  12 if(printk_ratelimit())
  13         dev_dbg()
  14
  15 Causes the ratelimiting to spam the kernel log with the "callbacks suppressed"
  16 message below, even while the dev_dbg it is supposed to rate limit wouldn't
  17 print anything because DEBUG is not defined for this device.
  18
  19 [  533.803964] retire_playback_urb: 852 callbacks suppressed
  20 [  538.807930] retire_playback_urb: 852 callbacks suppressed
  21 [  543.811897] retire_playback_urb: 852 callbacks suppressed
  22 [  548.815745] retire_playback_urb: 852 callbacks suppressed
  23 [  553.819826] retire_playback_urb: 852 callbacks suppressed
  24
  25 So use dev_dbg_ratelimited() instead of this construction.
  26
  27 Signed-off-by: Sander Eikelenboom <linux@eikelenboom.it>
  28 Signed-off-by: Takashi Iwai <tiwai@suse.de>
  29 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  30
  31 ---
  32  sound/usb/pcm.c |    6 +++---
  33  1 file changed, 3 insertions(+), 3 deletions(-)
  34
  35 --- a/sound/usb/pcm.c
  36 +++ b/sound/usb/pcm.c
  37 @@ -1419,9 +1419,9 @@ static void retire_playback_urb(struct s
  38          * The error should be lower than 2ms since the estimate relies
  39          * on two reads of a counter updated every ms.
  40          */
  41 -       if (printk_ratelimit() &&
  42 -           abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
  43 -               snd_printk(KERN_DEBUG "delay: estimated %d, actual %d\n",
  44 +       if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
  45 +               dev_dbg_ratelimited(&subs->dev->dev,
  46 +                       "delay: estimated %d, actual %d\n",
  47                         est_delay, subs->last_delay);
  48
  49         if (!subs->running) {