| Summary: | powernow-k8 not working w/ 2.6.19+ kernels | ||
|---|---|---|---|
| Product: | Gentoo Linux | Reporter: | Joshua Hoblitt <j_gentoo> |
| Component: | [OLD] Core system | Assignee: | Daniel Drake (RETIRED) <dsd> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | duaneg, j_gentoo, kernel |
| Priority: | High | ||
| Version: | unspecified | ||
| Hardware: | AMD64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Package list: | Runtime testing required: | --- | |
| Attachments: |
2.6.21 config
2.6.21 config w/o CONFIG_X86_POWERNOW_K8 2.6.21 config w/ CONFIG_ACPI_PROCESSOR & CONFIG_X86_POWERNOW_K8 dep fix |
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Description
Joshua Hoblitt
2007-05-15 00:57:14 UTC
Created attachment 119291 [details]
2.6.21 config
Looks like it might be similar to this: http://bugzilla.kernel.org/show_bug.cgi?id=8075 The comments there suggest it is caused by PowerNow requiring ACPI to be loaded first. I see you have PowerNow compiled into the kernel and ACPI as a module. Could you try reversing that, so: CONFIG_X86_POWERNOW_K8=m CONFIG_X86_ACPI_CPUFREQ=y That way ACPI should be loaded first, I believe. Maybe this is a stupid thing to say, but I had the same problem, and it was fixed by turning "Cool'n'Quiet" on in the BIOS. And I thought the same thing(about ACPI) when I had the problem. It doesn't really matter what it is configured like. (In reply to comment #3) > Maybe this is a stupid thing to say, but I had the same problem, and it was > fixed by turning "Cool'n'Quiet" on in the BIOS. Powernow is enable in the bios on all of the systems affected by this bug, it was the first thing I checked. And as I said, it was prevously working on these systems. (In reply to comment #2) > Looks like it might be similar to this: > http://bugzilla.kernel.org/show_bug.cgi?id=8075 > > The comments there suggest it is caused by PowerNow requiring ACPI to be loaded > first. I see you have PowerNow compiled into the kernel and ACPI as a module. > Could you try reversing that, so: > > CONFIG_X86_POWERNOW_K8=m > CONFIG_X86_ACPI_CPUFREQ=y > > That way ACPI should be loaded first, I believe. Nice catch! Compling them both in fixes the problem. As does building them both as modules and then loading powernow-k8 by hand as the ACPI module has already been loaded. This is a kconfig bug as you should not be able to select CONFIG_X86_POWERNOW_K8=y while CONFIG_X86_ACPI_CPUFREQ=m I just sent a possible patch to LKML: http://lkml.org/lkml/2007/5/15/352 Duane, what made you suggest CONFIG_X86_ACPI_CPUFREQ in the comments above? As far as I can see, the upstream bug only references the ACPI processor driver (CONFIG_ACPI_PROCESSOR) as a dependency. Curiosity aside, the most recent comments here indicate that is a fix. Actually, I suspect it there may be more to it. Joshua, what happens if you try the following configuration: CONFIG_X86_ACPI_CPUFREQ=y CONFIG_X86_POWERNOW_K8=n (no, that's not a typo) [Sidenote, I think if the grounds for that patch are correct, it's not a complete fix: the module itself should be modified to depend on the X86_ACPI_CPUFREQ object too, so that modprobe loads them in the right order] (In reply to comment #7) > Duane, what made you suggest CONFIG_X86_ACPI_CPUFREQ in the comments above? As > far as I can see, the upstream bug only references the ACPI processor driver > (CONFIG_ACPI_PROCESSOR) as a dependency. To be honest, it was a mistake. I didn't pick up on the "ACPI processor module" comment and assumed that ACPI_CPUFREQ was what was needed. > Curiosity aside, the most recent comments here indicate that is a fix. Looking at Joshua's config again it seems the ACPI processor module is being built as a module too. So actually I think CONFIG_X86_ACPI_CPUFREQ=y is just papering over the problem. Looking at the Kconfig and source it seems the controlling factor is actually X86_POWERNOW_K8_ACPI. This is an invisible config option with the following dependencies: depends on X86_POWERNOW_K8 && ACPI_PROCESSOR depends on !(X86_POWERNOW_K8 = y && ACPI_PROCESSOR = m) If it is defined powernow-k8.c calls acpi_processor_register_performance during initialisation. If not then it doesn't (and hence won't work on SMP). The current situation is certainly rather confusing, but I'm not sure what the correct fix is. An easy solution would be to make X86_POWERNOW_K8 depend on ACPI_PROCESSOR, but presumably that is not desirable. Maybe the best idea would be a warning in the X86_POWERNOW_K8 help text. How about something like this: "ACPI support is required for non-UP systems and requires ACPI_PROCESSOR to be selected. If ACPI_PROCESSOR is compiled as a module then this option must be too in order for ACPI support to be available." Let's wait for the results from comment #7 to get a better understanding. There are 2 possibilities: X86_ACPI_CPUFREQ's direct dependency on ACPI_PROCESSOR causes the processor module to be loaded which makes powernow-k8 work later on or X86_ACPI_CPUFREQ drives the performance states through generic ACPI tables and powernow-k8 is not needed at all (In reply to comment #7) > Actually, I suspect it there may be more to it. Joshua, what happens if you try > the following configuration: > > CONFIG_X86_ACPI_CPUFREQ=y > CONFIG_X86_POWERNOW_K8=n (no, that's not a typo) OK - with my config as: # # CPUFreq processor drivers # # CONFIG_X86_POWERNOW_K8 is not set CONFIG_X86_SPEEDSTEP_CENTRINO=m CONFIG_X86_ACPI_CPUFREQ=y No CPU scaling is enabled: ls /sys/devices/system/cpu/cpu0/cpufreq ls: cannot access /sys/devices/system/cpu/cpu0/cpufreq: No such file or directory Created attachment 119484 [details]
2.6.21 config w/o CONFIG_X86_POWERNOW_K8
# CONFIG_X86_POWERNOW_K8 is not set
CONFIG_X86_ACPI_CPUFREQ=y
CONFIG_ACPI_PROCESSOR=y . . # # CPUFreq processor drivers # CONFIG_X86_POWERNOW_K8=y CONFIG_X86_POWERNOW_K8_ACPI=y CONFIG_X86_SPEEDSTEP_CENTRINO=m # CONFIG_X86_ACPI_CPUFREQ is not set I get frequency scaling: ls -lad /sys/devices/system/cpu/cpu0/cpufreq/ drwxr-xr-x 3 root root 0 May 16 15:04 /sys/devices/system/cpu/cpu0/cpufreq/ So I believe that CONFIG_X86_POWERNOW_K8 needs to depend on CONFIG_ACPI_PROCESSOR on this system. Created attachment 119485 [details]
2.6.21 config w/ CONFIG_ACPI_PROCESSOR & CONFIG_X86_POWERNOW_K8
Created attachment 119488 [details]
dep fix
Is the fix this simple?
No, because on some configurations powernow-k8 can run just fine without acpi-processor. Dave Jones has accepted a patch that should appear (someday) in cpufreq.git. Please don't close the bug until it is fixed in Gentoo kernels. Fixed in gentoo-sources-2.6.21-r3 |
