tree 163e64e7cc930711c6502d6403beec54a7a5a75c
parent 3dc642a3984abb4e34b7514a5d569a50402410b7
author Brennan Shacklett <brennan@genyes.org> 1382372432 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1392328084 -0800

intel_pstate: Improve accuracy by not truncating until final result

commit d253d2a52676cfa3d89b8f0737a08ce7db665207 upstream.

This patch addresses Bug 60727
(https://bugzilla.kernel.org/show_bug.cgi?id=60727)
which was due to the truncation of intermediate values in the
calculations, which causes the code to consistently underestimate the
current cpu frequency, specifically 100% cpu utilization was truncated
down to the setpoint of 97%. This patch fixes the problem by keeping
the results of all intermediate calculations as fixed point numbers
rather scaling them back and forth between integers and fixed point.

References: https://bugzilla.kernel.org/show_bug.cgi?id=60727
Signed-off-by: Brennan Shacklett <bpshacklett@gmail.com>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>