The built-in SD card reader on my Thinkpad x60 has been always giving me headaches. It works reliably well, but when copying files my system becomes very unresponsive. The mouse is jerky and the CPU usage jumps through the roof. Obviously, DMA is not being used.

I couldn’t find much about it for a while but just today, when I included the chip id R5C822 of the reader in the search I found this thread.

However, instead of patching the source itself, it is quite easy to force the quirk when loading the sdhci module. Put the following in modprobe.conf or /etc/modprobe.d/local.conf and everything will be fine after you reboot.

options sdhci debug_quirks=2

You can also reload the module to check if it is fine even now.

  • umount any SD cards that you have mounted
  • modprobe -r sdhci-pci
  • modprobe -r sdhci
  • modprobe sdhci-pci

That’s all folks. Enjoy a true multitasking Linux.