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authorClemens Ladisch <clemens@ladisch.de>2011-02-10 16:15:44 +0100
committerTakashi Iwai <tiwai@suse.de>2011-02-10 18:53:29 +0100
commitb1d4f7f4bdcf9915c41ff8cfc4425c84dabb1fde (patch)
tree092e1575eb7c098670ebebd568566067e11a8c32 /sound/core
parenta6c47a85b8e7e4a8c47394607c5e5c43224b0892 (diff)
downloadlinux-b1d4f7f4bdcf9915c41ff8cfc4425c84dabb1fde.tar.gz
ALSA: hrtimer: handle delayed timer interrupts
If a timer interrupt was delayed too much, hrtimer_forward_now() will
forward the timer expiry more than once.  When this happens, the
additional number of elapsed ALSA timer ticks must be passed to
snd_timer_interrupt() to prevent the ALSA timer from falling behind.

This mostly fixes MIDI slowdown problems on highly-loaded systems with
badly behaved interrupt handlers.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Reported-and-tested-by: Arthur Marsh <arthur.marsh@internode.on.net>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/hrtimer.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/sound/core/hrtimer.c b/sound/core/hrtimer.c
index 7730575bfadd..07efa29dfd4a 100644
--- a/sound/core/hrtimer.c
+++ b/sound/core/hrtimer.c
@@ -45,12 +45,13 @@ static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
 {
 	struct snd_hrtimer *stime = container_of(hrt, struct snd_hrtimer, hrt);
 	struct snd_timer *t = stime->timer;
+	unsigned long oruns;
 
 	if (!atomic_read(&stime->running))
 		return HRTIMER_NORESTART;
 
-	hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution));
-	snd_timer_interrupt(stime->timer, t->sticks);
+	oruns = hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution));
+	snd_timer_interrupt(stime->timer, t->sticks * oruns);
 
 	if (!atomic_read(&stime->running))
 		return HRTIMER_NORESTART;