From: Dirk Brandewie Date: Tue, 25 Feb 2014 18:35:37 +0000 (-0800) Subject: intel_pstate: Change busy calculation to use fixed point math. X-Git-Tag: v3.14-rc5~9^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e66c176837462928a05a135bbe16cdce70536d6e;p=pandora-kernel.git intel_pstate: Change busy calculation to use fixed point math. Commit fcb6a15c2e (intel_pstate: Take core C0 time into account for core busy calculation) introduced a regression on some processor SKUs supported by intel_pstate. This was due to the truncation caused by using integer math to calculate core busy and C0 percentages. On a i7-4770K processor operating at 800Mhz going to 100% utilization the percent busy of the CPU using integer math is 22%, but it actually is 22.85%. This value scaled to the current frequency returned 97 which the PID interpreted as no error and did not adjust the P state. Tested on i7-4770K, i7-2600, i5-3230M. Fixes: fcb6a15c2e7e (intel_pstate: Take core C0 time into account for core busy calculation) References: https://lkml.org/lkml/2014/2/19/626 References: https://bugzilla.kernel.org/show_bug.cgi?id=70941 Signed-off-by: Dirk Brandewie Signed-off-by: Rafael J. Wysocki --- Reading git-diff-tree failed