4-bit SD Card mode

[Björn König]

> I'm not sure I like this at all.  The devices shouldn't be setting up
> the pins for that device.  In some cases, they can't know how to do
> that, and this is one of them.  The device has no way of knowing if
> all 4 wires are connected, or just 1 and the 'spare' lines are used
> for GPIO.  There are similar problems with the serial ports and the
> ethernet.

You're right. I also forgot that this affects all kind of AT91 controllers
and we don't know if this always works this way, not even with one
connected data line.

> Does the boot loader you are using at least store the board ID in the
> place that Linux expects it?

At first glance the U-Boot loader doesn't seem to do any board-specific
things. I may be mistaken. The board comes with a preinstalled Loader,
Linux distribution and a Linux kernel patched by the manufacturer of the
board. I'm not sure about this question, so I'll ask the manufacturer.

Björn