From 6dd22a2c22df9e270f25e90a85a3943fbc40d0db Mon Sep 17 00:00:00 2001 From: Srinivas Pandruvada Date: Thu, 31 Oct 2019 12:26:20 -0700 Subject: [PATCH] cpufreq: intel_pstate: Fix invalid EPB setting The max value of EPB can only be 0x0F. Attempting to set more than that triggers an "unchecked MSR access error" warning which happens in intel_pstate_hwp_force_min_perf() called via cpufreq stop_cpu(). However, it is not even necessary to touch the EPB from intel_pstate, because it is restored on every CPU online by the intel_epb.c code, so let that code do the right thing and drop the redundant (and incorrect) EPB update from intel_pstate. Fixes: 274d613465266 ("cpufreq: intel_pstate: Force HWP min perf before offline") Reported-by: Qian Cai Cc: 5.2+ # 5.2+ Signed-off-by: Srinivas Pandruvada [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 53a51c169451f..8ab31702cf6a2 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -847,11 +847,9 @@ static void intel_pstate_hwp_force_min_perf(int cpu) value |= HWP_MAX_PERF(min_perf); value |= HWP_MIN_PERF(min_perf); - /* Set EPP/EPB to min */ + /* Set EPP to min */ if (boot_cpu_has(X86_FEATURE_HWP_EPP)) value |= HWP_ENERGY_PERF_PREFERENCE(HWP_EPP_POWERSAVE); - else - intel_pstate_set_epb(cpu, HWP_EPP_BALANCE_POWERSAVE); wrmsrl_on_cpu(cpu, MSR_HWP_REQUEST, value); } -- 2.39.5