I've decided to write up something that I've been aware of for some time, but that didn't really bother me that much, since I've been waiting for the situation to improve quietly. The basic observation is: My trusty X60s uses less power when on battery on Windows than on Linux. This situation hasn't changed significantly despite the appearance of powertop to trim the number of processor wakeups per second thus enabling the processor to stay in deep sleep states for longer time and improvements in the Xorg intel video driver. I get arround 3.3 wakeups per second minimally when my Xorg/KDE is not active, with laptop using 9.1 W (as reported by powertop). When Xorg/KDE is running, with one konsole to monitor usage with powertop, I get arround 13 wakeups per second and power usage of 9.4 W. All the measurements are done with LCD brightness on the lowest level, wireless interfaces disabled, and all power saving features that powertop can detect enabled. Processor is in C3 state 99.9% of the time. I tried removing various driver modules that I didn't use at the time (irda, pcmcia, ethernet, sound), but no change. Windows power monitoring tool from Lenovo reports power usage of 6.5 W under the same LCD brightness level and with wireless disabled. This was tested under Linux 2.6.26-rc8 (some git level after the rc8 release). Older versions of the kernel didn't show any statistically significant differences. powertop is version 1.10, and the software used under Windows XP is Lenovo ThinkVantage Power Manager. Since I doubt that Windows XP has less wakeups per second than my Linux setup, I guess there are still a couple of IBM specific power saving registers/controls that can be tweaked so that the laptop uses less power. Does anybody have any idea on what would that be? Any friendly contacts at lenovo? Thanks Vedran Rodic -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
