I Ported Coreboot to the ThinkPad X270

(dork.dev)

121 points | by todsacerdoti 6 hours ago

6 comments

  • amiga-workbench 4 hours ago
    I wonder if this can help with the extremely irritating bug (intentional?) on the X270 where if you give it a third party 9-cell battery, it will raise CPU_PROCHOT all the damn time, and my processor would drop to below 1Ghz clock speeds.

    Back when I used to have an X270 I had a shell script that ran on boot which poked a register to disable thermal throttling handling. Not at all ideal, but it made the machine usable in the absence of official Lenovo batteries which they stopped manufacturing pretty damn quickly.

    • muniter 2 hours ago
      Nice to finally know what was happening to my x270 after so many years. Well good thing it doesn't happen when connected to power nowadays is my home server
    • inamberclad 25 minutes ago
      Oh almost certainly. PROCHOT is programmable.
    • 65a 2 hours ago
      Possibly. Usually this is handled by the embedded controller, and not sure if that was reversed or not. You may be able to tristate the GPIO line that tells the CPU that a pin means PROCHOT, which would allow you to ignore the ECs attempts to do this.
    • rasz 22 minutes ago
      Thinkpads do same thing when detecting 65W supply instead of 90W despite you only need 90W if running full tilt while charging.
    • nxobject 2 hours ago
      Do you think it could also be due to an ACPI table?
      • amiga-workbench 2 hours ago
        Its possible. I know from the BIOS revision changelogs that the T470 did get a patch to fix this, but the X270 never did.
  • BobbyTables2 2 hours ago
    How did OP debug this without a serial port?

    I’ve messed around with porting coreboot on two desktop platforms but always had the benefit of a HW serial port…

    • 65a 2 hours ago
      You can sometimes find the serial lines if you are careful. Otherwise you can use the flashrom to store the output, and read it back out after each failure. It is much easier to just poke around and find the serial if you can, either from schematics (it seems the author has these) or by hand with a lot of patience or board scrying.
    • katdork 1 hour ago
      because the x280 and x270 are similar enough I didn't need to try very hard to get it to post or boot a live USB to further investigate (effectively acting as a decent template for me to work off of)

      The console viewing itself was provided by `cbmem -1`, which I could run via a NixOS live USB with nixpkgs#coreboot-utils

  • reductum 2 hours ago
    Atom feed is malformed :(
    • katdork 1 hour ago
      sorry, I'll look into it
  • mattv8 3 hours ago
    What I would give for a wife that would enjoy tinkering with me.
    • notpushkin 2 hours ago
      Seek and thou shalt find. Just don’t be too pushy on the romantic side of things.
      • mattv8 2 hours ago
        Too late for me then I suppose, I'm married with two kids.
  • brcmthrowaway 4 hours ago
    Was AI Used?
    • katdork 1 hour ago
      Hi! As the author, no! I take a hard line stance against AI use myself. It's just not for me.
    • wetpaws 3 hours ago
      Does it matter?
      • fragmede 2 hours ago
        I will only accept ethically sourced, free-trade blog posts, written by somebody with cherry MX browns on their hardware keyboard, written while riding on donkey in the jungles of Peru, being a digital nomad and not paying local income taxes, using NFT money to pay the bills, thank you very much!
  • periodjet 2 hours ago
    This is absurdly trans-coded.

    Ah, todsacerdoti. ;)

    • katdork 1 hour ago
      I am a trans woman, yes :o

      (the user who posted my blog post is not me :p)