[coreboot] SeaBIOS and USB UHCI keyboard support

Kevin O'Connor kevin at koconnor.net
Thu Oct 1 03:03:17 CEST 2009

On Wed, Sep 30, 2009 at 09:18:21PM +0200, Peter Stuge wrote:
> Kevin O'Connor wrote:
> > The support in SeaBIOS is currently 1029 lines of code - it is a
> > direct, no nonsense, just make it work implementation.
> I think that is wonderful! Good job!


> > The next thing I am planning to look at is basic ohci keyboard
> > support, and then fleshing out the current keyboard support (eg,
> > auto-repeat, keyboard leds).
> The USB option ROM is still a tricky point. How to make it co-exist
> with USB support in SeaBIOS?

As Stefan pointed out, there can be only one driver of a usb
controller.  Anything else would be too fragile.

> If the option ROM works out well, maybe it could instead offer the
> keyboard services?

Yes - an option ROM can support keyboard.  However, a real 16bit
option ROM implementation is going to impose the same constraints on
libpayload as SeaBIOS.  Alternatively, the option rom could give up
support for vm86 mode callers and reserve lots of high ram to avoid
those constraints.  It still wouldn't be simple - the rom would need
to implement the bios calls for disk and kbd (seabios src/disk.c
src/kbd.c src/bregs.h src/entryfuncs.S = 1792 lines of code) and may
need to implement self uncompression (to reduce its rom code size).
I'd say it's doable, but not easy.


More information about the coreboot mailing list