Red Hat Bugzilla – Bug 52866
/proc/cpuinfo reports wrong info on unplugged thinkpad
Last modified: 2007-04-18 12:36:44 EDT
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.2) Gecko/20010809 Description of problem: When the laptop boots while unplugged, the wrong info ends up in /proc/cpuinfo. It reports CPU speeds at low as 187 mhz. It is not consistent in the cpu speed it reports when it boots unplugged. When the machine is plugged in and you boot, it reports a cpu speed around 1ghz. The information in cpuinfo isn't updated if you plug or unplug the machine while running. When the kernel thought it was on a 186 mhz machine it was running VERY slow, which is why I noticed this, I thought something was broken in mozilla or x. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1.unplug laptop 2.reboot 3.check funky speed in /proc/cpuinfo Actual Results: current output of /proc/cpuinfo: processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 8 model name : Pentium III (Coppermine) stepping : 10 cpu MHz : 697.419 cache size : 256 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 mmx fxsr sse bogomips : 1392.64 Expected Results: I would expect the actual processor speed to be reported, ie ~1000 when plugged in, and slower otherwise, but I wouldn't expect it to go as low as 187. This affects the performance of the machine very badly, and I thought something in roswell or X was very broken. Additional info: I upgraded to roswell 2 from a 7.1 install. The machine is a A22m.256M RAM.
Did something like this happen with 7.1 as well ?
Yes, I put in the hard drive that had 7.1 in it, and I did indeed see the same behavior. I had installed the kernel upgrade patch, however, the kernel-2.4.3-12.i686.rpm package.
For older laptops this is out of our hands (you'd need to know magic bios extensions) for newer stuff Red Hat 9 includes support for CPU scaling where we have info.