Success: Native gfx init on T500 with 1680x1050 display working w/o VGA blob - coreboot

19 Nov 2016


      Hi folks,
already since a while, there exists a hardware mod for the Thinkpad T500 which allows to run a quadcore CPU from from the Q9000-QX9300 series using Coreboot [1]. After trying various Coreboot configurations, I managed to make the current coreboot-master (e39a8a9c092ed66686632d591ec84ed7a6165a50) work on such a Quadcore-modded T500 with the Q9000 CPU [2]. What is really stunning: Although this T500 has one of the "believed-unsupported" 1680x1050 screen, even without the VGA blob and without microcode updates I get Seabios output using native gfx init!
However, there are some small issues:
- sometimes the screen is a little garbled, similar to the bug I reported for my X60s in [3]. It's not that bad, however and only affects booting.
- the memtest86+ payload does not boot (or it boots but shows no image, I don't know. Is it possible to make memtest86+ use the  1680x1050 resolution?).
- when booting the Debian Jessie installer, selecting the default VGA mode does not work. However, selecting mode 7 (1680x1050 VESA) works fine.
- when booting into an installed Debian Jessie base system, the grub screen (from Debian, not a coreboot payload) is not visible unless you set GRUB_GFXMODE=1680x1050 in grub.cfg and rewrite it.
Since I haven't reassembled the machine yet, I haven't done any extensive testing, didn't try virtualization etc. However, installing Debian Jessie worked fine. Power consumption in idle is very good as for this CPU (13,5-19W, depending on screen brightness).
I am attaching my config to this post and will try to run board-status script as soon. Very happy with my T500 so far - huge thanks to the Coreboot developers!
Cheers, Daniel
[1] https://thinkpad-forum.de/threads/199129-Core2-Quad-mit-Coreboot-Libreboot-a...
[2] http://ark.intel.com/products/40480/Intel-Core2-Quad-Processor-Q9000-6M-Cach...
[3] https://ticket.coreboot.org/issues/80