Comment 24 for bug 14907

(In reply to comment #23)
> (In reply to comment #22)
> I have tried disabling dma, and commented out the relevant modules in /etc/modules
> Afer a reboot the card reader worked, but I was without dma!

The proper way of disabling DMA for CD drives is to not enable it in
/etc/hdparm.conf. It is not enabled by default, so I assume you changed it at
some time (check with "sudo hdparm /dev/cdrom"). There is no need to disable it
entirely, DMA usually works fine for hard drives and the like.

> I haven't yet tried the breezy live cd as I imagine that dma will again not be
> enabled by default, and the test would therefore not be very revealing. Is
> there any way I can enable dma on breezy live cd?

Right, DMA for CD-ROMs is still disabled, exactly for the reason that it seems
to break random things. However, you can always enable it per-device with

 sudo hdparm -d 1 /dev/<device>