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Date: Tue, 17 Nov 2015 18:15:26 -0800 From: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com> To: Alexandra Yates <alexandra.yates@...ux.intel.com> Cc: rjw@...ysocki.net, lenb@...nel.org, viresh.kumar@...aro.org, linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, root <root@...-s-fedora22.jf.intel.com> Subject: Re: [PATCH V2] SKL intel_pstate update MSR values when changing governors On Tue, 2015-11-17 at 17:58 -0800, Alexandra Yates wrote: > From: root <root@...-s-fedora22.jf.intel.com> You need to fix the git config ... The change itself is OK. Thanks, Srinivas > > 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: root <root@...-s-fedora22.jf.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; > } > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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