I agree that this is confusing. I disagree that this is the fix. The fix is actually a lot more complicated, and it involves the removal of the /proc/acpi/.../power file modification to /sysfs names from cpuidle, and fixing powertop. On Sat, 12 Dec 2009, Youquan,Song wrote: > C1: type[C1] promotion[--] demotion[--] > C2: type[C3] promotion[--] demotion[--] > > While > /sys/devices/system/cpu/cpux/cpuidle/state1 > ACPI FFH INTEL MWAIT 0x0 > 1 > C1 > 1000 > 58312355 > 323873 > > /sys/devices/system/cpu/cpux/cpuidle/state2 > ACPI FFH INTEL MWAIT 0x10 > 17 > C2 > 500 > 83706664055 > 18926855 > > In /proc, "type[C3]" mean acpi C3, but from its title "C2:" mean processor > support max C-state is ACPI C2. No, type[C3] means type C3, and C2: means the 2nd C-state, which in this case happens to be type C3 because a useful state between type C1 and type C3 was not exported. This is unusual, but not rare. There were systems before NHM that did it this way. > In /sys, there is no any information show that this processor support ACPI C3. > > these issues are rooted cause to ACPI C2 miss at some platforms, ACPI C3 is > wrongly mapped to C2. There is nothing "wrong" with ACPI C2 being mapped to a C3 type state. The original output above is correct. The output below is not correct. > This patch will invalidate ACPI C2 when platform does not support ACPI C2. > > After apply the patch, the C-state information in /proc and /sys are reasonable > > /proc/acpi/processor/CPUx/power > C1: type[C1] promotion[--] demotion[--] > C2: <not supported> > C3: type[C3] promotion[--] demotion[--] That said, I agree this confuses uses, and that doesn't even start to get into hardware C-states vs ACPI C-states and powertop output... I believe that powertop is bugged in how it reverse-engineers the C-state names and displays hardware names. I think that we should put the hardware names in /sysfs and it should simply use them -- but more on that later. thanks, Len Brown, Intel Open Source Technology Center -- 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
