Messages in this thread Patch in this message | | | From | Alexandra Yates <> | Subject | [PATCH V3] SKL intel_pstate update MSR values when changing governors | Date | Wed, 18 Nov 2015 14:58:40 -0800 |
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When changing from powersave to performance governors Intel_pstate fails to update the MSR values that reflect the max_perf_pct to 100%. For instance in SKL reading rdmsr 0x774:
Governor MSR max_perf_pct ========= ======== ============ Powersave 80002808 100% Powersave 80002008 80% Performance 80002028 [error] 100% Performance 80002828 [expected] 100%
The line label [error] shows the culprit. At this point the MSR should reflect the max_perf_pct that is 100%, that corresponds to MSR 80002828 as shown on the next line of the example. Which is the maximum performance for the Performance governor. Instead it holds back the MSR value previously set by the Powersave, in this case 80002028.
This patch allows the system to print the correct MSR value 80002828 that corresponds to the 100% max_perf_pct when changing from powersave to performance governors.
For more information on the MSR values for SKL please visit ISDM under Managing HWP.
Signed-off-by: Alexandra Yates <alexandra.yates@linux.intel.com> --- drivers/cpufreq/intel_pstate.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 2e31d09..0eeb7da 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1242,6 +1242,8 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) policy->max >= policy->cpuinfo.max_freq) { pr_debug("intel_pstate: set performance\n"); limits = &performance_limits; + if (hwp_active) + intel_pstate_hwp_set(); return 0; } -- 1.9.1
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