Comment 6 for bug 777321

Marc -- This should have been fixed with this patch:

http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-natty.git;a=commitdiff;h=26daa1ed40c6b31b4220581431982814c47c608a

... which was included in 2.6.37

Can you try this:

Create /etc/modprobe.d/test

add the following to the file:
options sdhci debug_quirks=0x40

then:
rmmod sdhci_pci
rmmod sdhci
modprobe sdhci_pci

See if that changes the sdcard behaviour