Rumor has it that some pci devices can't tolerate < 32bit accesses.
Although I have never met one.

hopefully not bridge devices?

The two factors together suggest that
for generic code it probably makes sense to operate on 32bit
quantities, and just to ignore the read-only portion.

The code for regular devices seems to use 16-bit accesses, so
I think it's best to stay consistent. Or do you want to change this too?

-- 
MST