Hello all, For power saving purposes I would like to be able to modify the CPU speed of an AMD LX (LX800) at runtime. Ultimately I would like to have a cpufreq driver for this, but for the moment I tried writing to the CPU PLL register directly (MSR 0x4c000014). This seems to work, "most of the time". I can set the CPU frequency all the way from 200MHz to 600MHz. I can see this has immediate effect by benchmarking and also by monitoring power consumption. However occassionally the system will reset, segfault, or otherwise act strange when writing to the MSR. The datasheet says "When using this register to change the PLL frequencies, the CHIP_RESET bit should be set." I was not sure whether changing the clock multipliers and dividers qualifies as "changing the PLL frequencies". Has anyone else tried this? If this is not officially supported, is there any other way to modify CPU frequency at runtime (without having to reset the chip)? Thanks, Guillermo -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
