[Intel-gfx] source-based replacement for video bios on ivybridge -- I'm stuck!

[ron minnich]

Dear intel graphics experts:

I am looking at trying to get coreboot to move away from binary video
bios on google chromebook platforms. The current target is an
ivybridge system. We'd like to get minimal graphics going with a
source-based startup code in coreboot, such that we can avoid the
issues that come with binary video bioses.

The good news is that the kernel driver works fine without a video
bios having been run -- the new samsung chromebox/chromebook work in
this manner.

As an experiment, I have used cocinnelle to extract the relevant
driver functions from the kernel (in this case 3.4.2) and am running
them in user mode. I've had good luck with prototyping hardware
drivers for coreboot in user mode, and this approach is *almost*
working on this graphics hardware.

You can see the result here: http://pastebin.com/3e77Y66C

The I2C is working, and I'm recovering EDID and the mode. I can
control the panel backlight. I can easily program the GTT and other
simple functions.

The issue now is that I am not able to get the link trained. I figure
I'm misordering or missing some crucial step, and on the off chance
that some one of you can look at that output and say "Ron you idiot!
You're missing *this* step" I've posted it.

If anyone has any thoughts on this I'd welcome them. This thing is
close, and I feel it is possible, but I've obviously got something
wrong.

Thanks in advance for any help or advice you can give me!

ron