[coreboot] T400 screen issue / EDID handling

Hello,

I allready contacted Francis from libreboot and he forwared me to this 
list, because it seems to be an issue regarding coreboot.

I have flashed a Lenovo T400 with libreboot.

The T400 has an Intel GPU and I am able to use it with an external 
display connected to the onboard vga-port.

The issue is, that I can't use the internal display, which is an 
1440x900 Samusung LTN141WD-L05, EDID dump:

https://paste.debian.net/plainh/b3699c60

It seems like the internal screen is powered on while booting but it 
stays black.

Francis assumes that this is due to bugs in how coreboot handles the 
EDID.

Here is an EDID dump of a working display:

http://paste.debian.net/plainh/776705d5

Anyone is able to help?

Thanks in advance!