Re: [Bug 39822] SDHC cards no longer recognized on AT91 based board

[Chris Ball <cjb@laptop.org>]

Hi, thanks for the bug report.  Adding linux-mmc@ and some atmel driver
folks to CC.

On Thu, Jul 28 2011, bugzilla-daemon@bugzilla.kernel.org wrote:
> Prior to 3.0.0 the FoxG20 board (Atmel AT91SAM9G20) could boot and use
> both micro SD and SDHC card to contain its root file system. With the
> advent of the 3.0.0 kernel the micro SDHC card is unable to mount the
> root file system.
> 
> Comparing the relevant part of dmesg for 2.6.38.6 (and it worked on
> 2.6.39):
> ...
> Waiting for root device /dev/mmcblk0p2...
> mmc0: host does not support reading read-only switch. assuming write-enable.
> at91_mci at91_mci: Timeout waiting end of packet
> mmc0: new SDHC card at address 1234
> mmcblk0: mmc0:1234 SA04G 3.67 GiB
>  mmcblk0: p1 p2 p3
> ...
>
> to the same dmesg section for 3.0.0 :
> ...
> Waiting for root device /dev/mmcblk0p2...
> mmc0: error -110 whilst initialising SD card
> at91_mci at91_mci: Timeout waiting end of packet
> mmc0: error -110 whilst initialising SD card
> [no further progress]
>
> Non "HC" SD cards work as expected in 3.0.0

If no-one on the CC list has any ideas, would you be interested in
trying to bisect this change?

Another possibility would be adding printks before all of the -ETIMEDOUT
lines in core/* and host/at*, in order to see which one you're hitting
(and therefore which operation is causing the initialization to fail).
But a full bisection would be more conclusive.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child