on 01/07/2011 01:52 Vitaly Magerya said the following: > I got the dumps for Linux (it appears that you can't just read > /dev/mem on there, you need to mmap it). The summary of differences > between FreeBSD and Linux right after the boot: > > DB00: 01 -> 00 > P80D: 06:08:00:00 -> 06:08:4C:00
Not sure what these two are. > PCP0: 1D -> BF > PCP1: 1D -> BF These reflect advertised OS power-management capabilities and appear to be correct. > BRTL: 00 -> 1E This seems to be a variable holding current BRighTness Level. It seems to be ralated to _BCM/_BQC/etc methods used acpi_video driver. > VDRV: 00 -> 01 Looks like this variable should tell if OS has ACPI Video driver, to be precise if _BCL method was invoked at least once. Looks like in your case the driver doesn't attach for some reason?.. Unfortunately, I don't remember if or where you provided your dmesg. > > (Note that C1ON is 0 just as with FreeBSD, and yet powertop does > report C2 and C4). Hmm, this is the strangest thing. According to my analysis of all the ASL code that we extracted if C1ON is zero, then no deep C-states should be reported by _CST method. As such, I wonder where does Linux get C-states information from? Or what else could be going on here. Maybe they somehow query them directly from HW by-passing ACPI in this case... Actually, it seems that they have them simply hardcoded: http://lxr.linux.no/#linux+v2.6.39/drivers/idle/intel_idle.c#L171 I am not sure how to check on Linux which cpuidle driver is being used. If you know, could please check that? And if the driver is intel_idle, then there is no mystery, they use those hardcoded values. > Then, after about 4 minutes of uptime, C1ON changes to 1 (and > powertop still reports the same states). OK, no difference here. So it's probably done by firmware based on some unknown logic. -- Andriy Gapon _______________________________________________ freebsd-acpi@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-acpi To unsubscribe, send any mail to "freebsd-acpi-unsubscr...@freebsd.org"
