| From 75707a9601a64e14b883cab7e164632e51c00de2 Mon Sep 17 00:00:00 2001 |
| From: Clemens Ladisch <clemens@ladisch.de> |
| Date: Thu, 10 Feb 2011 16:15:44 +0100 |
| Subject: [PATCH] ALSA: hrtimer: handle delayed timer interrupts |
| |
| commit b1d4f7f4bdcf9915c41ff8cfc4425c84dabb1fde upstream. |
| |
| 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> |
| Signed-off-by: Takashi Iwai <tiwai@suse.de> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/sound/core/hrtimer.c b/sound/core/hrtimer.c |
| index 7730575..07efa29 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; |
| -- |
| 1.7.4.4 |
| |
