Most recent kernel where this bug did not occur:2.6.11.12 Distribution:Fedora Core 3 Hardware Environment:Athlon 64 X2 4400+, MSI K8N Neo4 (Nforce4), 4G DDR Software Environment: Problem Description:The Usermode speed governor can set the two processors on the chip to different speeds. When the cores are out of sync there can be system crashes or other bad behavior. I had both a system crash and a failure on a kernel make which reported and irreproducible error. The following error message is issued by the kernel, Aug 7 20:51:42 nimitz kernel: powernow-k8: error - out of sync, fid 0xc 0x2, vid 0xa 0x12 Aug 7 20:51:42 nimitz kernel: Warning: CPU frequency is 1000000, cpufreq assumed 2000000 kHz. The X2 cores seem to need to run at the same clock speed. Currently the cores are managed as two separate CPUs, for the purposes of clock speed management they need to be treated as a single entity, i.e. the when when changing the speed the kernel needs to change them both simultaneously. I've switched to the performance governor for the moment and everything seems stable. p.s. I tried to load the ondemand governor, but the kernel won't accept that one for A64 X2s. Steps to reproduce:
mark.langsdorf@amd.com said: The old driver (driver version 1.20 and earlier, in 2.6.11 kernels and earlier) wasn't dual-core aware and would attempt to transition frequencies on each core without respect to the other. This would cause some warning messages but I'm surprised that it caused system stability. The latest driver (driver version 1.40 and later, in 2.6.12 kernels and later) is dual core aware and uses the cpus field of the cpufreq_policy struct to keep track of them. It doesn't have any known stability problems nor does it generate warning messages on dual-core systems. I think we're covered, here. So please test a 2.6.12.x or 2.6.13-rcY kernel.
any update on this? e.g. new test results?
I'm assuming this issue is already fixed in recent 2.6 kernels. Please reopen this bug if it's still present in kernel 2.6.16.5.