Any work being done on MMC write protect?

I've written some ioctls (for the 2.6.29 kernel) which implement SEND_WRITE_PROT and SET_WRITE_PROT. However I can't get them to work -- the former throws a CRC error and the latter returns success but doesn't actually write-protect the device.

I was wondering if anybody else had done any work in this area.

If anybody wants the code, I can send a patch along.

-ed falk