Summary: | sys-kernel/gentoo-sources-2.6.34-r2 the lowest CPU frequency on AC off | ||
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Product: | Gentoo Linux | Reporter: | Vladimir <v_2e> |
Component: | [OLD] Core system | Assignee: | Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel> |
Status: | RESOLVED UPSTREAM | ||
Severity: | normal | ||
Priority: | High | ||
Version: | unspecified | ||
Hardware: | AMD64 | ||
OS: | Linux | ||
Whiteboard: | |||
Package list: | Runtime testing required: | --- |
Description
Vladimir
2010-07-15 13:43:05 UTC
What "governor" are you using? Please provide that information and reopen this bug report. I use different CPU governors depending on the situation (for example, my cpufreqd daemon watches the temperature and switches from 'ondemand' governor to 'powersave' governor if the temperature is too high). When I turn off the AC adapter, it doesn't matter which governor I use - the highest available frequency is 800MHz. I tried to switch betweed different governors with AC adapter off - I can do that, but it just doesn't help. What laptop are you using? I found this: If the battery pack is removed and the laptop is powered by AC only, the CPU downclocks to the lowest multiplier and remains locked in low speed. This happens irrespective of the scaling method in use (kernelspace or userspace) and of the frequency governor selected (ondemand, performance, etc.). (In reply to comment #4) > What laptop are you using? > > I found this: > > If the battery pack is removed and the laptop is powered by AC only, the CPU > downclocks to the lowest multiplier and remains locked in low speed. This > happens irrespective of the scaling method in use (kernelspace or userspace) > and of the frequency governor selected (ondemand, performance, etc.). > I'm using MSI MegaBook S430X. My main concern is about the fact that it worked perfectly with 2.6.29 kernel. Some news. Well, not actually news, but the results of a small investigation. Today I tested few different versions of gentoo-sources ( 2.6.29-gentoo-r6, 2.6.30-gentoo-r8, 2.6.30-gentoo-r9, 2.6.31-gentoo-r6, 2.6.32-gentoo-r13, 2.6.33-gentoo-r2, 2.6.34-gentoo-r3 and 2.6.35-gentoo). Looks like the 'bug appearance line' is between 2.6.29-gentoo-r6 and 2.6.30-gentoo-r8. In 2.6.29-gentoo-r6 kernel everything works fine if the following configure options are set to 'Y': CONFIG_X86_ACPI_CPUFREQ=y CONFIG_X86_POWERNOW_K8_ACPI=y If I set one of these two to 'M' (build as a module), CPU will stick to the lowest possible frequency with AC turned off. Any of the 2.6.30+ kernels which I tested work regardlessly of these two settings - CPU sticks to the lowest frequency with AC adapter turned off. By the way, looks like in 2.6.30+ kernel there is no option named 'CONFIG_X86_POWERNOW_K8_ACPI'. Instead, there is an option named 'CONFIG_X86_POWERNOW_K8', but this is probably the same. I have also notices one interesting thing, which is present in 2.6.30+ kernels and is absent in 2.6.29 kernel. Namely, with the newer kernels when CPU temperature reaches ~84 C, something (I do not really know, what exactly) limits the highest available frequency to 800 MHz (the lowest physically available for my CPU), and after some seconds of work in such regime the temperature lowers and CPU switches to the 2,2 GHz back again. BUT! Sometimes, it doesn't switch back to high frequencies. Instead, it remains sticked to the lowest one (800 MHz) for an unlimited period of time, I guess. In such case unplugging and plugging back the AC adapter makes it work properly again (makes higher frequencies available again). With 2.6.29 kernel my CPU may be heated up to 90+ C degrees and nothing limits its frequency. By the way, my userspace programs can see the correct battery charge level and properly detect the AC adapter on/off transitions only with few recent kernels (and 2.6.29 is not one of them). Maybe, this is related somehow. I hope this information helps finding a solution. Regards, Vladimir. Hello! I just wanted to report that with gentoo-2.6.36 kernel my laptop still works with the lowest available CPU frequency - 800MHz. But now the CPU temperature can increase any high (at least it seems so) with no frequency limitation around 85C. I must say that it is very inconvenient to work on the lowest available frequency. That is why it is very strange for me that there is no substantial interest to this problem among the developers. It looks like a serious but. Or maybe I'm wrong? Regards, Vladimir Please post this upstream at http://bugzilla.kernel.org and post the link back here. (In reply to comment #8) > Please post this upstream at http://bugzilla.kernel.org and post the link back > here. > Done. Here is a link: https://bugzilla.kernel.org/show_bug.cgi?id=23412 Watching upstream bug |