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Power management in Linux is a bit wacky still. I was running a super ancient Linux distro on this laptop for years, and had two weird incidents. In one, I was

Power management in Linux is a bit wacky still. I was running a super ancient Linux distro on this laptop for years, and had two weird incidents. In one, I was trying to tweak power settings manually, and somehow got the CPU fan stuck on "full-speed" for something like 6 months. Then later I installed either PowerTOP or TLP or some other tool I don't know, and it recalibrated my power settings.... immediately the fan stopped going full-speed, and it would only turn on when the CPU was really chugging. Fast forward to today, I upgraded to Ubuntu 20.04. Just letting the machine idle after boot-up runs the CPU fan continuously at low speed. Opening a browser sends it into full-speed mode until I close the browser (virtually any page). But it's the same machine, and same version of Firefox. So, something about this newer kernel + OS has resulted in the fan spinning way more than the old kernel + OS. Trying to figure out how or why leads you nowhere, because of course it's all specific to your hardware and whatever in the kernel has changed. Now you might think, "OK, just turn on power-saving, the fans should be silenced." Nope. Tried every single power tweak that exists, and I can't force the fans to quiet. I can make the CPU run dog slow, but the fans keep chugging. Which is really annoying when all you want is a few minutes of peace and quiet.

Thev00d00 5y ago
if it's years old perhaps it heatsinks are just a bit full of cruft nowadays?
quijoteuniv 5y ago
In my cases, several Mac transformed to Linux and some windows transforms, they all run better in Linux. You can check with lm_sensors which reads the temperature of the sensors, specially on the cpu, then repaste them, you will see you gain 10 degrees Celsius or more on badly thermal pasted cpus. I also upped the minimum fan speed (by modifying a file on startup) lm_sensors reads that too, so upped 1000 revs were still is quite quiet and that helps. All of this while having CPUPower on conservative from startup. Peace and quiet :) I am curious: why do you have a throwaway account for posting this? Edit: is that machine even able to run another OS than Linux? If not Linux is awesome and can even run on that machine :)
- beermonster 5y ago
  > In my cases, several Mac transformed to Linux and some windows transforms, they all run better in Linux. That concurs with my experience also.
onli 5y ago
With the Intel processors suddenly being hotter with a new kernel, I'd always have a look at the cpu frequency scaling. That's where stuff changed, and the new modules for that could simply work worse for older processors. Especially if it's not all that old, but also not Skylake yet. https://wiki.archlinux.org/title/CPU_frequency_scaling#CPU_frequency_driver https://wiki.archlinux.org/title/CPU_frequency_scaling#CPU_f... If it's not that, check that the temps are actually high. If they are not, adjusting the fan curve could be possible. https://wiki.archlinux.org/title/Fan_speed_control https://wiki.archlinux.org/title/Fan_speed_control lists some options (nbfc looks nice and is new to me), your laptop might have some vendor specific solution like thinkfan.
- throwaway984393 5y ago
  If you're not running a Thinkpad (I'm not) then there's not much that works for controlling power, fan, etc. I've tried everything I can find that works in this OS and it has almost no effect. Basic cpufreq controls work, but they only slow down the CPU, the fans keep spinning more than on the old OS. And most of the /sys/ settings that exist (like no_turbo or the power governors) simply don't work for whatever reason (and it's a Skylake CPU). I'm not surprised that there's regressions, but I am a little surprised at how poor the hardware compatibility testing is (I guess there isn't any?). The only way to know for sure if a complete system will keep working when the software changes is to test it, send test results in, look for bugs, fix those, etc. It's surprising that Linux has been developed for 30 years and there's no official test suite for hardware compatibility. All of us should be running a test suite that automatically sends reports back to the kernel devs, but for whatever reason Linus's testing model is "put out an alpha release and see if anybody complains". And there's virtually no documentation for 90% of the controls in the kernel; you have to be a kernel hacker to know what values to set on what controls and what they'll even do.
  - onli 5y ago
    I can only echo that sentiment, in a way. I was also surprised when looking at the hardware support with new kernels for my (very old) thinkpad how much just did not work anymore. IIRC, undervolting that processor had been possible before (what I looked at to make the fan quieter), but the API got removed without replacement. And the gpu could not be used for video acceleration in the browser, something that seemed to have worked when the laptop was new in Windows (at least the reviews from that time stated better support for videos with higher resolution than possible when I checked, it might also have been caused by better cpu hardware acceleration). Though some things get better with time, gpu acceleration for videos in the browser is possible now in Linux in general and works well, maybe it even works with that old gpu. For this specific issue: If the fans do not spin down when the processor clocks down the thermal control of the laptop is broken. If that worked better in earlier systems, then it wasn't BIOS controlled then but is now, or the other way around. I'd really look at whether nbfc supports it. And also at what is possible in the BIOS, a Skylake laptop with UEFI bios might have a configurable fan curve. And I'd also check what the temperature sensors output, this issue might be caused by simply more dust in the machine than it had earlier. Or, I once had the effect of my system being louder after a move, until I realized the system was equally noisy, my environment got quieter. It's easy to be wrong with those things.

Thev00d00 5y ago

if it's years old perhaps it heatsinks are just a bit full of cruft nowadays?

quijoteuniv 5y ago

In my cases, several Mac transformed to Linux and some windows transforms, they all run better in Linux. You can check with lm_sensors which reads the temperature of the sensors, specially on the cpu, then repaste them, you will see you gain 10 degrees Celsius or more on badly thermal pasted cpus. I also upped the minimum fan speed (by modifying a file on startup) lm_sensors reads that too, so upped 1000 revs were still is quite quiet and that helps. All of this while having CPUPower on conservative from startup. Peace and quiet :) I am curious: why do you have a throwaway account for posting this? Edit: is that machine even able to run another OS than Linux? If not Linux is awesome and can even run on that machine :)

beermonster 5y ago
> In my cases, several Mac transformed to Linux and some windows transforms, they all run better in Linux. That concurs with my experience also.

onli 5y ago

With the Intel processors suddenly being hotter with a new kernel, I'd always have a look at the cpu frequency scaling. That's where stuff changed, and the new modules for that could simply work worse for older processors. Especially if it's not all that old, but also not Skylake yet. https://wiki.archlinux.org/title/CPU_frequency_scaling#CPU_frequency_driver https://wiki.archlinux.org/title/CPU_frequency_scaling#CPU_f... If it's not that, check that the temps are actually high. If they are not, adjusting the fan curve could be possible. https://wiki.archlinux.org/title/Fan_speed_control https://wiki.archlinux.org/title/Fan_speed_control lists some options (nbfc looks nice and is new to me), your laptop might have some vendor specific solution like thinkfan.

throwaway984393 5y ago
If you're not running a Thinkpad (I'm not) then there's not much that works for controlling power, fan, etc. I've tried everything I can find that works in this OS and it has almost no effect. Basic cpufreq controls work, but they only slow down the CPU, the fans keep spinning more than on the old OS. And most of the /sys/ settings that exist (like no_turbo or the power governors) simply don't work for whatever reason (and it's a Skylake CPU). I'm not surprised that there's regressions, but I am a little surprised at how poor the hardware compatibility testing is (I guess there isn't any?). The only way to know for sure if a complete system will keep working when the software changes is to test it, send test results in, look for bugs, fix those, etc. It's surprising that Linux has been developed for 30 years and there's no official test suite for hardware compatibility. All of us should be running a test suite that automatically sends reports back to the kernel devs, but for whatever reason Linus's testing model is "put out an alpha release and see if anybody complains". And there's virtually no documentation for 90% of the controls in the kernel; you have to be a kernel hacker to know what values to set on what controls and what they'll even do.
- onli 5y ago
  I can only echo that sentiment, in a way. I was also surprised when looking at the hardware support with new kernels for my (very old) thinkpad how much just did not work anymore. IIRC, undervolting that processor had been possible before (what I looked at to make the fan quieter), but the API got removed without replacement. And the gpu could not be used for video acceleration in the browser, something that seemed to have worked when the laptop was new in Windows (at least the reviews from that time stated better support for videos with higher resolution than possible when I checked, it might also have been caused by better cpu hardware acceleration). Though some things get better with time, gpu acceleration for videos in the browser is possible now in Linux in general and works well, maybe it even works with that old gpu. For this specific issue: If the fans do not spin down when the processor clocks down the thermal control of the laptop is broken. If that worked better in earlier systems, then it wasn't BIOS controlled then but is now, or the other way around. I'd really look at whether nbfc supports it. And also at what is possible in the BIOS, a Skylake laptop with UEFI bios might have a configurable fan curve. And I'd also check what the temperature sensors output, this issue might be caused by simply more dust in the machine than it had earlier. Or, I once had the effect of my system being louder after a move, until I realized the system was equally noisy, my environment got quieter. It's easy to be wrong with those things.