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From: Pierre Ossman <pierre@ossman.eu>
To: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>,
	linux-mmc@vger.kernel.org, magnus.damm@gmail.com,
	sameo@openedhand.com, pb@handhelds.org, philipp.zabel@gmail.com,
	Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: TMIO MMC: full patchset.
Date: Tue, 29 Sep 2009 20:32:35 +0200	[thread overview]
Message-ID: <20090929203235.7426cb1f@mjolnir.ossman.eu> (raw)
In-Reply-To: <20090929132058.GC6934@console-pimps.org>

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On Tue, 29 Sep 2009 14:20:58 +0100
Matt Fleming <matt@console-pimps.org> wrote:

> 
> I'm not sure that propagating this magical 400kHz constant around the
> MMC code is the best way to go. It could do with a #define.
> 
> You're the second person to run into issues with the lower limit
> initialisation patch. Does anybody know where that value came from? Is
> it definitely the best value to use or has it just been picked out of
> the air?

The MMC and SD specs state that init must be done at < 400 kHz. We
originally used the lowest possible freq. the controller could handle,
but there was one controller who went so ridiculously low that it caused
other problems.

Re this patch, I'd think it would be more sensible to lower the init
frequency a bit than some retry logic. It is possible to init a card
and for it to end up in a weird state, so we should have margins
already at the first attempt.

Rgds
-- 
     -- Pierre Ossman

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  reply	other threads:[~2009-09-29 18:32 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-29 12:52 TMIO MMC: full patchset Ian Molton
2009-09-29 13:20 ` Matt Fleming
2009-09-29 18:32   ` Pierre Ossman [this message]
2009-09-30 11:41 ` Magnus Damm
2009-09-30 20:15   ` Ian Molton
2009-10-01  1:30     ` Magnus Damm
2009-10-01  1:39       ` Andrew Morton
2009-10-01 10:21         ` Ian Molton
2009-10-02  6:17         ` Magnus Damm
2009-10-02  7:23           ` Ian Molton
2009-10-02  7:55             ` pHilipp Zabel
2009-10-01 10:19       ` Ian Molton
2009-10-02  5:46         ` Magnus Damm
2009-10-02  7:31           ` Ian Molton
2009-10-02  7:57             ` Magnus Damm
2009-10-02 18:14               ` Ian Molton
2009-10-03 13:11                 ` Magnus Damm
2009-10-04  0:00                   ` Ian Molton
2009-10-04  5:05                     ` Magnus Damm
     [not found]                       ` <c09aa50a0910040851g51640678r5d1f79a50b01164a@mail.gmail.com>
2009-10-04 16:12                         ` Phil Blundell
2009-10-04 17:19                           ` Ian Molton
2009-10-05  6:49                         ` Magnus Damm
2009-09-30 16:59 ` Philipp Zabel
2009-09-30 21:49   ` Ian Molton

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