[patch] snd hda suspend latency: shorten codec read

Ingo Molnar
2007-11-16T12:59:17Z

snd hda suspend latency goes down a second via the patch below.

Ingo

------------->
Subject: snd hda suspend latency: shorten codec read
From: Ingo Molnar <mingo@elte.hu>

not sleeping for every codec read/write but doing a short udelay and
a conditional reschedule has cut suspend+resume latency by about 1
second on my T60.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
sound/pci/hda/hda_intel.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux/sound/pci/hda/hda_intel.c
===================================================================
--- linux.orig/sound/pci/hda/hda_intel.c
+++ linux/sound/pci/hda/hda_intel.c
@@ -555,7 +555,8 @@ static unsigned int azx_rirb_get_respons
}
if (!chip->rirb.cmds)
return chip->rirb.res; /* the last value */
- schedule_timeout_uninterruptible(1);
+ udelay(10);
+ cond_resched();
} while (time_after_eq(timeout, jiffies));

if (chip->msi) {