Unpartitioned MMC size detection mismatch

[Lea Gris]

Today I discovered a bug with size detection on removable media MMC card
on an USB2.0 reader.

Put a 256MB partioned card in the reader.
Udev create /dev/sdb (for main media) and /dev/sdb1 .. 2.. 3 for
partitions on the MMC card.

Then put in a cleared (without partion table) smaller card in the reader.
Say it is an all blank 128MB MMC previously cleared with:
dd if=/dev/zero of=/dev/sdb

The system keep believing the newly inserted 128MB MMC has 256MB because
it can't find size information with no partition table and it didn't
reset size upon card change.

Had to reboot for Ubuntu to actually see the real size of the not
partitioned 128MB card.

Could not even correctly partition the 128MB card because it idsplayed
as a 256MB device in gparted or even fdisk.

How could I prevent this from happening or reset the drivers so it realy
see the size of a new inserted card with no partition?

Partitioned MMC update media size correctly upon insertion though.

-- 
Léa Gris