| author | Len Brown <len.brown@intel.com> | |
| Wed, 19 Jan 2011 01:48:27 +0000 (20:48 -0500) | ||
| committer | Len Brown <len.brown@intel.com> | |
| Thu, 17 Feb 2011 22:08:46 +0000 (17:08 -0500) | ||
| commit | 14796fca2bd22acc73dd0887248d003b0f441d08 | |
| tree | 45281c00405077fe1a099d585588d2173ee90fea | tree | snapshot (tar.xz tar.gz zip) |
| parent | 100b33c8bd8a3235fd0b7948338d6cbb3db3c63d | commit | diff |
intel_idle: disable NHM/WSM HW C-state auto-demotion
Hardware C-state auto-demotion is a mechanism where the HW overrides
the OS C-state request, instead demoting to a shallower state,
which is less expensive, but saves less power.
Modern Linux should generally get exactly the states it requests.
In particular, when a CPU is taken off-line, it must not be demoted, else
it can prevent the entire package from reaching deep C-states.
https://bugzilla.kernel.org/show_bug.cgi?id=25252
Signed-off-by: Len Brown <len.brown@intel.com>
Hardware C-state auto-demotion is a mechanism where the HW overrides
the OS C-state request, instead demoting to a shallower state,
which is less expensive, but saves less power.
Modern Linux should generally get exactly the states it requests.
In particular, when a CPU is taken off-line, it must not be demoted, else
it can prevent the entire package from reaching deep C-states.
https://bugzilla.kernel.org/show_bug.cgi?id=25252
Signed-off-by: Len Brown <len.brown@intel.com>
| arch/x86/include/asm/msr-index.h | diff | blob | history | |
| drivers/idle/intel_idle.c | diff | blob | history |