Am Mittwoch, den 25.11.2015, 23:33 +0000 schrieb Łukasz Dobrowolski:
I would like to port coreboot to one of my laptops (ThinkPad X140e and X120e). Both of them have AMD APU-s.
Awesome! Welcome to coreboot!
I would be grateful if somebody could take a look at attachments and tell me how challenging the task appears to be. I read and searched for information about those for few days now.
What I found (apart from attachments): X120e: Logical mainboard schematics I'm 90% sure I can get my hands on physical mainboard schematics if needed. I have detailed pictures of the mainboard. X140e: I can make detailed mainboard pictures. I haven't searched for schematics of this one yet.
I just took a brief look at the X140e lspci output and the AMD Kabini device seems to be used.
The AGESA code, AMD’s platform initialization code, for that device is in the repository in `src/vendorcode/amd/agesa/f16kb/`.
So chances are pretty good you get so much up and running (RAM for example) that you have a way to access error messages for debugging issues.
Make sure you have a way to recover from a bad flash (external programmer) and find out, how you can get debug messages. Alexandru, Edward, and Paul some other folks might be able to give you hints how they did it on their AMD laptop ports. I don’t know if they used USB/EHCI debug dongle or something else.
With laptops you might run into issues with the embedded controller, but that very much depends on your device how early these issues show. If they prevent you from getting to the payload or just if you are not able to use possible function keys.
Please be aware of the fact, that with AMD laptops, the goal of a fully free system is also hard to achieve, due to ATOMBIOS, which is hard to replace. Especially as there is opposition from the Linux Radeon module maintainers. But one could argue, that this is unrelated from coreboot.