From: Pierre Ossman <pierre@ossman.eu>
To: Tobias Diedrich <ranma@tdiedrich.de>
Cc: SDHCI development <sdhci-devel@lists.ossman.eu>,
linux-kernel@vger.kernel.org
Subject: Re: QUIRK_FORCE_HISPD (was: Re: Ricoh R5C822 and QUIRK_FORCE_DMA)
Date: Sun, 6 Sep 2009 15:30:18 +0200 [thread overview]
Message-ID: <20090906153018.6c03d942@mjolnir.ossman.eu> (raw)
In-Reply-To: <20090801051716.GA28791@yamamaya.is-a-geek.org>
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On Sat, 1 Aug 2009 07:17:16 +0200
Tobias Diedrich <ranma@tdiedrich.de> wrote:
> Pierre Ossman wrote:
> > > On a related note, I had a little time to play a bit more with my
> > > R5C822 and found that I can also force-enable HISPD mode, which
> > > boost performance further.
> > >
> >
> > This seems odd. What frequency is the controller reporting?
> >
> > It could be that they originally wanted the controller to be
> > high-speed, but that they had stability problems and turned it off.
> > There is at least one other controller that went through that scenario.
>
> I assume thats host->max_clk?
> The controller seems to report 33MHz for that value.
>
Ah, then your controller is most likely not really high-speed. You're
getting a bit more performance as you are forcing things out-of-spec
and you're lucky enough that it still happens to work. :)
Rgds
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prev parent reply other threads:[~2009-09-06 13:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-30 22:45 Ricoh R5C822 and QUIRK_FORCE_DMA Tobias Diedrich
2009-05-13 17:59 ` Pierre Ossman
2009-05-13 18:09 ` [Sdhci-devel] " Garrett D'Amore
2009-06-09 22:41 ` QUIRK_FORCE_HISPD (was: Re: Ricoh R5C822 and QUIRK_FORCE_DMA) Tobias Diedrich
2009-06-13 10:53 ` Pierre Ossman
2009-08-01 5:17 ` Tobias Diedrich
2009-09-06 13:30 ` Pierre Ossman [this message]
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