Issues with SD reader on XO

[Denver Gingerich]

While testing the performance of the SD interface on the XO, an Eee
PC, and a generic reader (see the results at http://ossguy.com/?p=27),
I found that the XO was significantly slower than the other devices in
almost all tests.  In many cases, it was less than half as fast as the
Eee PC, and in one case the write speed was 350 KiB/s, which is
virtually unusable.

I am wondering if this is a known issue as I haven't seen any mention
of it on the wiki or in Trac.  Is the SD interfacing hardware actually
supposed to run this slowly?

Additionally, I encountered I/O errors similar to those in
http://dev.laptop.org/ticket/6078 when using one of the cards.  This
card worked fine with the generic reader on another laptop.  Any
thoughts on why this might be happening?

On a more physical note, the slot in the XO interferes with the lock
slider on some SD cards.  When a card is inserted, the side of the
slot can catch on the lock slider of the card, moving it from the
unlocked to the locked position during insertion.  It is possible that
the lock slider could be moved to an in-between position during
insertion; I'm not sure if this would have an impact on the I/O
errors.  In any case, it would be a good idea to fix this in future
hardware revisions.

If you think some of these issues would be best logged to Trac, let me
know and I'll do that.

Denver