From: "Heiko Stübner" <heiko@sntech.de>
To: Doug Anderson <dianders@chromium.org>
Cc: Addy Ke <addy.ke@rock-chips.com>,
Jaehoon Chung <jh80.chung@samsung.com>,
Seungwon Jeon <tgih.jun@samsung.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
Alim Akhtar <alim.akhtar@samsung.com>,
Sonny Rao <sonnyrao@chromium.org>,
Andrew Bresticker <abrestic@chromium.org>,
linux-rockchip@lists.infradead.org, robh+dt@kernel.org,
pawel.moll@arm.com, mark.rutland@arm.com,
ijc+devicetree@hellion.org.uk, galak@codeaurora.org,
linux@arm.linux.org.uk, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: dts: Bump SD card pin drive strength up on rk3288-evb
Date: Sun, 21 Dec 2014 15:04:13 +0100 [thread overview]
Message-ID: <2971473.Y1akaDeraL@phil> (raw)
In-Reply-To: <1418244929-8254-1-git-send-email-dianders@chromium.org>
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@chromium.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
prev parent reply other threads:[~2014-12-21 14:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-10 20:55 [PATCH] ARM: dts: Bump SD card pin drive strength up on rk3288-evb Doug Anderson
2014-12-21 14:04 ` Heiko Stübner [this message]
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