| Summary: | gentoo-sources-2.6.16-r13 cpufreq reports wrong frequency on Pentium 4. | ||
|---|---|---|---|
| Product: | Gentoo Linux | Reporter: | Timothy Stotts <devel> |
| Component: | [OLD] Core system | Assignee: | Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel> |
| Status: | RESOLVED UPSTREAM | ||
| Severity: | normal | ||
| Priority: | Normal | ||
| Version: | 2006.0 | ||
| Hardware: | x86 | ||
| OS: | Linux | ||
| URL: | http://bugzilla.kernel.org/show_bug.cgi?id=7186 | ||
| Whiteboard: | |||
| Package list: | Runtime testing required: | --- | |
| Attachments: |
Values of all cpufreq entires under /sys/devices/system/cpu/cpu0/cpufreq/
/proc/cpuinfo when driver is NOT loaded /proc/cpuinfo when driver is IS loaded Kernel configuration, gentoo-sources-2.6.16-r13 |
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Created attachment 92367 [details]
Values of all cpufreq entires under /sys/devices/system/cpu/cpu0/cpufreq/
Created attachment 92368 [details]
/proc/cpuinfo when driver is NOT loaded
Created attachment 92370 [details]
/proc/cpuinfo when driver is IS loaded
Created attachment 92371 [details]
Kernel configuration, gentoo-sources-2.6.16-r13
Please confirm that this is reproducible on the latest stable kernel (currently 2.6.17), and if so, check whether or not it is fixed in the latest development kernel (currently 2.6.18-rc4) I only have one (1) Pentium 4 machine, which is a dedicated server that cannot be rebooted frequently. I will report back upon updating to 2.6.18 stable (when it is released). Confirmed that bug is upstream problem. Reproducible with 2.6.18 vanilla. http://bugzilla.kernel.org/show_bug.cgi?id=7186 |
Have a desktop with an old Pentium 4 processor (1300 MHz). gentoo-sources-2.6.16-r13 Expected: /proc/cpuinfo to display a current and valid CPU MHz at all times Actual: While 'p4-clockmod' is loaded, the 'cpu MHz' value in /proc/cpuinfo does not correspond to a real frequency. How to Reproduce: (1) configure a Pentium 4 machine with kernel with cpufreq compiled-in and p4-clockmod as module (bug unaffected by compiled-in/module) (2) examine /proc/cpuinfo to notice realistic frequency value (3) #modprobe p4-clockmod (4) notice that /proc/cpuinfo displays an unrealistic frequency value (5) #modprobe -r p4-clockmod (6) notice that /proc/cpuinfo displays realistic frequency value again Timing a perl script that does 10*10^8 integer additions, the top cpufreq frequency setting is in fact the same speed as the normal frequency. All intermediate values do in fact adjust the processor speed. However, the value displayed in /proc/cpuinfo is invalid so long as the cpufreq driver is loaded.