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Looking for kernel mod to allow P50/P51/P52/... control of both system fans to prevent overheating

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Looking for kernel mod to allow P50/P51/P52/... control of both system fans to prevent overheating

#1 Post by joshuaalbert » Sun Jun 07, 2020 8:47 am

Dear all,

I've owned P50/51/52 thinkpads and always had trouble with overheating when running linux. The problem is because there are two system fans but thinkpad-acpi only has support to control one fan (the left one nearest the CPU -- thankfully it's nearest). The second fan on the right side stays at idle speed all the time. On these machines -- and any other thinkpad with two fans -- the GPU does not have its own fan, but rather relies on the dual system fans to provide the cooling. When both system fans work, it is adequate. This can be experienced in Windows where the drivers support both fan operations and things run cool.

There is a long online trail of unsolved forum posts of other people trying to solve the same fan problem. If you are one of these people, please post your experience here so we can gather attention to devs.
The problem and solution (which needs to be implemented by a dev) is fully articulated here: https://forums.developer.nvidia.com/t/h ... ed/71621/4.
Many people falsely think that the overheating happens because the second fan is controlled by nvidia, but this is false. The second fan is a system fan.

In order to get dual fan control in linux we need a small kernel-level modification:
1. a patch whitelisting P50/P51/P52/... notebooks or at least add a module option to enable it
2. a patch adding write access to the second fan on P50/51/52/...
3. a patch for 'fancontrol' to control two fans.

Is there anyone with a P5X machine who is qualified to patch a kernel? Looking for:

A. the thinkpad-acpi devs
B. the kernel devs of various distros

Again, post your desires to see this change here and on other forums, where I'll be pasting this call out.

UPDATE: Linux 5.8 will finally support two fans! See here: https://www.phoronix.com/scan.php?page= ... ontrol-5.8



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