Re: [patch] snd hda suspend latency: shorten codec read

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Friday, 16 of November 2007, Ingo Molnar wrote:
> 
> 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>

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

> ---
>  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) {
> 
> 



-- 
"Premature optimization is the root of all evil." - Donald Knuth
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