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.
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
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.
pretty cool work!
Though it leaves me wondering if coreboot/bios code can directly interface with thermal-management and battery controller , shouldn't it be feasible to improve upon battery life by exposing some interface to OS, like apple laptops ?
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.
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
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.
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
Oh almost certainly. PROCHOT is programmable.
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.
Thinkpads do same thing when detecting 65W supply instead of 90W despite you only need 90W if running full tilt while charging.
Do you think it could also be due to an ACPI table?
Its possible. I know from the BIOS revision changelogs that the T470 did get a patch to fix this, but the X270 never did.
pretty cool work! Though it leaves me wondering if coreboot/bios code can directly interface with thermal-management and battery controller , shouldn't it be feasible to improve upon battery life by exposing some interface to OS, like apple laptops ?
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…
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.
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
Atom feed is malformed :(
sorry, I'll look into it
What I would give for a wife that would enjoy tinkering with me.
Seek and thou shalt find. Just don’t be too pushy on the romantic side of things.
Too late for me then I suppose, I'm married with two kids.
This gave me a good chuckle :)
Was AI Used?
Hi! As the author, no! I take a hard line stance against AI use myself. It's just not for me.
Respect.
Does it matter?
on HN in 2026, I’d say it’s never mattered more lol
HN? You mean Molt News?
This is absurdly trans-coded.
Ah, todsacerdoti. ;)
I am a trans woman, yes :o
(the user who posted my blog post is not me :p)