[coreboot] Getting an WXGA+ LED MVA panel to work on T400: "G141C1-L01"

Arthur Heymans arthur at aheymans.xyz
Mon Sep 26 16:51:44 CEST 2016

Merlin Büge <toni at bluenox07.de> writes:
>> Not sure why Linux doesn't get the display running though. But as Linux
>> sometimes reuses register settings set by the firmware there is a slight
>> chance that fixing coreboot would make it work in Linux too.
> You mean, despite the kernel log messages (which say 104500),
> it might be that Linux is actually using the clock settings from coreboot, that
> is 87075?

Linux should be able to modeset the display (mostly) independently from coreboot
(misconfigured) settings. So if the display does not work in linux I
think something else is wrong.

> So, to check for that - could I temporarily hardcode the correct clock settings
> in coreboot/libreboot?

This https://review.coreboot.org/#/c/16741/ should set graphic clock
correcly for g4x gpu's. Since it does the same as linux I don't expect
it to work but feel free to try it.

There is a slight chance that this display uses a single channel LVDS,
in this case the p2 clock divisor needs to be set to 14 instead of 7,
which you can hardcode in src/northbridge/intel/gm45/gma.c

> [0] http://www.display-solution.com/pdf/tft-displays/Chi%20Mei%20Innolux/G141C1-L01_V2.0_20100802.pdf
>From what I can understand from datasheets this is a dual channel LVDS
(as expected)...
> -- 
> Merlin Büge <toni at bluenox07.de>

Kind regards
Arthur Heymans

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