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Description of problem: C3 power state only shows up in /proc/acpi/processor/CPU*/power if the machine boots off battery. This is on a new HP dv6519tx laptop. Version-Release number of selected component (if applicable): kernel-2.6.23.8-63.fc8 How reproducible: Always Steps to Reproduce: 1. Boot laptop while connected to AC 2. cat /proc/acpi/processor/CPU0/power 3. Notice only C1 and C2 are shown: active state: C0 max_cstate: C8 bus master activity: 00000000 maximum allowed latency: 2000 usec states: C1: type[C1] promotion[--] demotion[--] latency[001] usage[00011849] duration[00000000000000000000] C2: type[C2] promotion[--] demotion[--] latency[017] usage[00149276] duration[00000000000174245808] 4. Remove AC power cable 5. Results don't change 6. Boot laptop when *not* connected to AC 7. cat /proc/acpi/processor/CPU0/power 8. C1, C2, and C3 are shown 9. Plug laptop in AC 10. C3 state remains, and is used (counters increase, shown in powertop, etc) Additional info: will attach acpidump, plus what I *think* are the _CST tables, from acpidump --addr 0x7FED2425 --length 0x5EA and acpidump --addr 0x7FED2A0F --length 0x85 I've checked that the table contents are the same regardless of whether the laptop was booted off AC or battery and regardless of whether the laptop is currently plugged in or not
Created attachment 289712 [details] acpidump
Created attachment 289713 [details] CPU0 _CST (binary format)
Created attachment 289714 [details] CPU1 _CST This is a dual core T7100, so CPU1 is really the second core of CPU0
When booting on battery, /proc/acpi/processor/CPU0/power is: active state: C0 max_cstate: C8 bus master activity: 00000000 maximum allowed latency: 2000 usec states: C1: type[C1] promotion[--] demotion[--] latency[001] usage[00000183] duration[00000000000000000000] C2: type[C2] promotion[--] demotion[--] latency[001] usage[00009437] duration[00000000000008537003] C3: type[C3] promotion[--] demotion[--] latency[057] usage[00046654] duration[00000000000323653138]
Still happens, with kernel-2.6.23.15-137.fc8
Upgraded BIOS, same result. No change to CST/IST tables in the update (the address changed in SSDT, but thats it)
The latest BIOS changes the CST to not depend on the power cord status any more. Its still a linux bug rather than a BIOS bug, since Windows didn't behave this way with the older BIOS, but since its not reproducible with the newer BIOS, I guess its WONTFIX.