Comment 14 for bug 389784

Problem is really that with stock kernel, after suspend, the SD card is remounted as mmcblkp1 instead of mmcblkp0.

I can confirm that suggestion as in #9 indeed solves the problem. I recompiled the kernel with CONFIG_MMC_UNSAFE_RESUME and problem is solved. I did not yet test, however, what happens to the right-hand removable SD card slot upon suspend. If card is not removed during suspend, all should be fine.
Perhaps a sync just before suspend is a sensible idea?

What would help is applying this patch, so you can set the option to the module rather then at compile time only: http://www.gossamer-threads.com/lists/linux/kernel/1152175