linux-kernel - RE: [PATCH] OMAP: HSMMC: Do not enable buffer ready interrupt if using DMA

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Date:	Wed, 1 Jul 2009 11:59:28 +0530
From:	"Gadiyar, Anand" <gadiyar@...com>
To:	"Gadiyar, Anand" <gadiyar@...com>,
	Jarkko Lavinen <jarkko.lavinen@...ia.com>
CC:	"pierre@...man.eu" <pierre@...man.eu>,
	Tony Lindgren <tony@...mide.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>
Subject: RE: [PATCH] OMAP: HSMMC: Do not enable buffer ready interrupt if
 using DMA

On Fri, May 22, 2009, Gadiyar, Anand wrote:
> On Wed, May 06, 2009, Gadiyar, Anand wrote:
> > On Tue, May 5, 2009, Jarkko Lavinen wrote: 
> > > On Tue, Apr 21, 2009 at 09:39:22AM +0200, ext Gadiyar, Anand wrote:
> > > > From: Anand Gadiyar <gadiyar@...com>
> > > > 
> > > > OMAP: HSMMC: Do not enable buffer ready interrupt if using DMA
> > > > 
> > > > This considerably reduces the number of interrupts during a transfer
> > > > and ought to result in some power saving.
> > > 
> > > I tried the patch with reading from the raw mmc block device to
> > > /dev/null with dd (with bs 32k and 1M).  I cannot see any
> > > difference in interrupt count from /proc/interrupts or in read
> > > speed. At least the patch works. Cpu was 34340es3.
> > > 
> > > I also trid without the patch just disabling the Buffer
> > > Read/write Ready bits from INT_EN_MASK which is then written to
> > > both MMCHS_IE and MMCHS_ISE.  Still no change in read speed nor
> > > mmc irq count.
> > > 
> > > Cheers
> > > Jarkko Lavinen
> > 
> > I discovered this while doing MMC writes. I did not check if there
> > was any difference during a read. I notice you have only tested with
> > MMC reads.
> > 
> > Here's what I get with and without the patch.
> > 
> > - Anand
> 
> 
> Any comments on this? Is it safe to merge?
> 
> Thanks,
> Anand

<snip>


Ping?

Patchwork link is:
http://patchwork.kernel.org/patch/19133/

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