Re: 2.6.20 mmc: problem with highspeed SD card

From: Pierre Ossman
Date: Thu Feb 15 2007 - 00:48:27 EST


Eugene Ilkov wrote:
> I have I/O errors with Transcend SD highspeed card 2GB/150x when it's
> mounted in r/w mode (cardreader on sharp sl-c1000)
> It works well if I reverse mmcv4 patch commited to 2.6.19-git2
> (http://lkml.org/lkml/2006/10/4/27)

That patch is not the same as you are referencing in the rest of your mail.

> I'm not experienced in mmc, but I figured out that problem is
> somewhere in mmc_read_switch_caps() and when i change cmd.arg value
> from 0x80FFFFF1 to 0x00FFFFF1 it works fine too
> What argument should have SD_SWITCH opcode?
>

The argument is correct, so I'm guessing that your controller might be a bit
flaky and not handle the new timing. Can you enable MMC_DEBUG and send over the
dmesg?

Rgds

--
-- Pierre Ossman

Linux kernel, MMC maintainer http://www.kernel.org
PulseAudio, core developer http://pulseaudio.org
rdesktop, core developer http://www.rdesktop.org
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