# Heat Issues with Laptop that are only present on gentoo

## Lyude

Hello, I installed Gentoo on my laptop after using Arch for a few months and noticed that my laptop in general seems to be running a lot hotter then it used to. Originally on arch, it would idle at around 37°C, and after completing a task that was likely to heat up the laptop the temperature would always quickly drop to around 40°C. Ever since I installed Gentoo, it will slowly heat up to around 47°C and stay there, and after running a task that heats up the laptop it takes very long time to cool down again. My battery life also seems to be affected by this. In addition, the laptop can heat up to over 90°C when I'm running stressful tasks (such as compiling something). I've looked all over the internet, and tried all the guides for Gentoo on power management but have had no luck. I'm assuming the problem has to be with my configuration, or with Gentoo itself (which, I'm really hoping is not the case). My laptop is a acer 6530g. If you need any more information regarding my setup feel free to ask.

EDIT: Forgot to mention, I have cpufreq-utils working along (partially) laptop-mode.

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## Hu

Do your fans run for the same duration and speed with both Gentoo and Arch?  How is your Gentoo kernel configured with respect to power management?  Did you start from one of Pappy's seeds or from defconfig?

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## Lyude

I can't really tell since I don't have a working installation of arch, on a LiveCD though it seems about the same, but that's using acpi -t to check the temp, so I don't know how well that compares to lm_sensors in accuracy. As far as I know though, there's no way to control the fan speed via software on this laptop, so I'd imagine fan speed probably doesn't have much to do with it.

As for the kernel config, I tried the config I had when I was running Arch to make my kernel in gentoo and it made no difference, I'm pretty sure I have all the modules I need for power management anyway.

As for Defconfig, I've never used it. I just normally use genkernel --menuconfig and load my config from there.

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## tristen

 *Lyude wrote:*   

> I can't really tell since I don't have a working installation of arch, on a LiveCD though it seems about the same, but that's using acpi -t to check the temp, so I don't know how well that compares to lm_sensors in accuracy. As far as I know though, there's no way to control the fan speed via software on this laptop, so I'd imagine fan speed probably doesn't have much to do with it.
> 
> As for the kernel config, I tried the config I had when I was running Arch to make my kernel in gentoo and it made no difference, I'm pretty sure I have all the modules I need for power management anyway.
> 
> As for Defconfig, I've never used it. I just normally use genkernel --menuconfig and load my config from there.

 

Which kernel are you using? All kernels >= 2.6.38 have power regressions.

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## Lyude

Latest Kernel version, 2.6.39 from gentoo-sources, with a BFQ patch from the Zen kernel added on.

What do you mean by power regressions though?

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## tristen

 *Lyude wrote:*   

> Latest Kernel version, 2.6.39 from gentoo-sources, with a BFQ patch from the Zen kernel added on.
> 
> What do you mean by power regressions though?

 

They have unfixed bugs which make (generally just laptops) consume more power than the previous versions. Try using 2.6.37 and see if you notice a difference.

See:

http://www.phoronix.com/scan.php?page=article&item=linux_mobile_uffda&num=1

http://www.phoronix.com/scan.php?page=article&item=linux_kernel_regress2&num=1

http://www.phoronix.com/scan.php?page=article&item=linux_2638_aspm&num=1

http://www.phoronix.com/scan.php?page=news_item&px=OTYwMQ

I think the fixes won't be in until 3.1 is out.

EDIT:

Hey, looking futher into the issue, it was isolated late june, and the short-term fix is to pass pcie_aspm=force to the kernel when booting.

What happens when you try that?

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## Lyude

I was running 2.6.39 on my Arch installation and this didn't happen, so I know it's not that.

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## cach0rr0

 *Lyude wrote:*   

> I was running 2.6.39 on my Arch installation and this didn't happen, so I know it's not that.

 

i guess the bigger point is:

-the kernel controls power management, inclusive of things like fan speed, triggers, etc. There are indeed userspace tools for managing certain portions, but more than anything those change/modify kernel defaults with respect to power management. 

-the kernel is the kernel is the kernel. 2.6.39 is 2.6.39. The exception being patched kernels, but unless they're patching something related to ACPI, the patches are irrelevant The Arch 2.6.39 kernel is built from the same set of sources (vanilla 2.6.39) as the gentoo 2.6.39 kernel. 

-it is known and confirmed not by gentoo, not by arch, but by the mainline kernel developers who provide both distros with their kernels, that >=2.6.38 have introduced power management regressions. Unless either distro is applying patches specifically for addressing the power management issue, you are affected by this. Whether that's THE issue for you is another matter entirely

Having said that, I concur with the other poster that you should at least *try* 2.6.37

Troubleshooting is a process of ruling things out often times. I think we would like to conclusively rule that out - not having an issue on arch with 2.6.39 does not conclusively rule that out.

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## Lyude

Alright, I'll give it a try then. I'll make another post when I have the results.

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## Lyude

Wow! Everything seems to work just fine now. Although it may have been the ambient temperature that actually made the big difference. Regardless, it's cooler now.

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## Elleni

one other thing to consider, is a bios update. I am installing gentoo on an acer aspire 5315 which had a heat problem too, I could not even unpack a stage4 backup without the laptop overheating and thus shutting down. A googlesearch told me that it had a problem with fans not spinning when laptop came back from idle or something like that. In fact Bios update to version 1.43 corrected that problem, so I thougth I should report.

Source: http://ubuntuforums.org/showthread.php?p=10786348

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## DepreTux

I had the same problem with gentoo kernel, so what I did was updating to gentoo-sources-3.0.1 and compiled with the same config.

It runs cooler and gives me a far better battery life.

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