RE: [PATCH]acpi c-states: Fix ACPI C3 is wrongly mapped to C2

Pallipadi, Venkatesh
2009-12-14T19:07:38Z

>-----Original Message-----
>From: Youquan,Song [mailto:youquan.song@linux.intel.com]
>Sent: Monday, December 14, 2009 5:13 AM
>To: linux@dominikbrodowski.net
>Cc: Dominik Brodowski; lenb@kernel.org; Pallipadi, Venkatesh;
>Liu, Kent; Guo, Chaohong; Song, Youquan; linux-acpi@vger.kernel.org
>Subject: Re: [PATCH]acpi c-states: Fix ACPI C3 is wrongly mapped to C2
>
>> > Yes, but what happens if there are two states of type C2?
>The whole concept
>> > of "type C<number>" and "state C<number>" was broken from
>the beginning...
>>
>> Sorry. In my mind, there is no two states of ACPI C2. If processor C3
>> above are mapped to ACPI C3, so processor C1 is mapped to ACPI C1,
>> processor C2 is mapped to ACPI C2.
>> Len Brown, Am I right?
>>
>> If I am wrong, I will file another patches for it.
>
>This patch handle the ACPI C2 invlidation on some platform.
>Another patch "acpi c-states: Fix multiply C-states name
>disturbance" will unify multiply C-states name.
>

I assume this patch is not needed with your other patch
"acpi c-states: Fix multiply C-states name
disturbance".

I don't like
/proc/acpi/processor/CPUx/power
C1: type[C1] promotion[--] demotion[--]
C2: <not supported>
C3: type[C3] promotion[--] demotion[--]

Because there are systems with more than one ACPI C3 C-state and this change will not help such systems. Also, this has potential to break applications like powertop that depend on current output format.

Thanks,
Venki