Date: Fri, 16 Nov 2007 15:21:08 +0100
Message-ID: <s5hpryamfu3.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Mark Lord <lkml@rtr.ca>, perex@perex.cz, Pavel Machek <pavel@ucw.cz>,
       Mark Lord <liml@rtr.ca>, Thomas Gleixner <tglx@linutronix.de>,
       len.brown@intel.com, Andrew Morton <akpm@linux-foundation.org>,
       linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org,
       rjw@sisk.pl, Len Brown <lenb@kernel.org>
Subject: Re: [patch] snd hda suspend latency: shorten codec read
In-Reply-To: <20071116125824.GA28082@elte.hu>
References: <20071115181418.GA6603@ucw.cz>
	<473C825E.3030307@rtr.ca>
	<20071115193424.GA31691@elte.hu>
	<20071115193612.GA751@elte.hu>
	<473CC6D4.2010909@rtr.ca>
	<20071116055531.GA16273@elte.hu>
	<20071116071522.GA1453@elte.hu>
	<20071116082146.GA14685@elte.hu>
	<20071116112317.GA12724@elte.hu>
	<20071116124319.GA21978@elte.hu>
	<20071116125824.GA28082@elte.hu>
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At Fri, 16 Nov 2007 13:58:24 +0100,
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>

Cute, I applied to ALSA tree now.  Thanks!


Takashi

> ---
>  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) {
> 
-
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