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Message-ID: <2971473.Y1akaDeraL@phil>
Date: Sun, 21 Dec 2014 15:04:13 +0100
From: Heiko Stübner <heiko@...ech.de>
To: Doug Anderson <dianders@...omium.org>
Cc: Addy Ke <addy.ke@...k-chips.com>,
Jaehoon Chung <jh80.chung@...sung.com>,
Seungwon Jeon <tgih.jun@...sung.com>,
Ulf Hansson <ulf.hansson@...aro.org>,
Alim Akhtar <alim.akhtar@...sung.com>,
Sonny Rao <sonnyrao@...omium.org>,
Andrew Bresticker <abrestic@...omium.org>,
linux-rockchip@...ts.infradead.org, robh+dt@...nel.org,
pawel.moll@....com, mark.rutland@....com,
ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
linux@....linux.org.uk, linux-arm-kernel@...ts.infradead.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: dts: Bump SD card pin drive strength up on rk3288-evb
Am Mittwoch, 10. Dezember 2014, 12:55:29 schrieb Doug Anderson:
> It seems that ever since (536f6b9 mmc: dw_mmc: Reset DMA before
> enabling IDMAC) landed upstream that SD cards have been very unhappy
> on rk3288-evb. They were a little unhappy before that change, but
> after that change they're REALLY unhappy.
>
> It turns out that the above fix happens to fix a corruption when
> reading card information during probe time. Without the fix we didn't
> detect that high speed SD cards could actually support high speed.
> With the fix we suddenly detect that they're high speed and we try to
> use them at 50MHz. That doesn't work so well on EVB with the default
> drive strength (maybe because there are two physical SD card slots
> hooked up to the same pin?).
>
> Fix the problem by bumping up the drive strength of the sdmmc lines.
>
> Signed-off-by: Doug Anderson <dianders@...omium.org>
> Fixes: 536f6b91d21b ("mmc: dw_mmc: Reset DMA before enabling IDMAC")
applied to my 3.19 dts-fixes branch
(after a slight modification of the subject: please use "ARM: dts: rockchip:")
Heiko
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