Many of existing SD controller chips have some nonstandard requirements, proprietary registers and hardware bugs, requiring additional handling.lspci reveals the name of the SD card reader:
SD Host controller: O2 Micro, Inc. Integrated MMC/SD Controller (rev 01)dmesg that there's a problem:
mmc0: Unknown controller version (16). You may experience problems.This is a message I've noticed while the computer is booting, I think for as long as I've used Linux, and in many different distributions.
There are several bug reports for this issue, but I haven't found any "additional handling". To read and write to SD cards, I use a USB card reader from PoundWorld.
One post I came across suggested there might be a fix coming in kernel 3.5, but I'm using 3.10 from Wheezy backports.
In the end I came across a way to disable the SD card driver so that the error message doesn't appear. Add:
blacklist sdhci-pcito /etc/modprobe.d/blacklist.conf.
This didn't take effect until I ran:
update-initramfs -uDebian forum.