4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chen Yu yu.c.chen@intel.com
[ Upstream commit 70f6bf2a3b7e40c3f802b0ea837762a8bc6c1430 ]
When maxcpus=1 is in the kernel command line, the BP is responsible for re-enabling the HWP - because currently only the APs invoke intel_pstate_hwp_enable() during their online process - which might put the system into unstable state after resume.
Fix this by enabling the HWP explicitly on BP during resume.
Reported-by: Doug Smythies dsmythies@telus.net Suggested-by: Srinivas Pandruvada srinivas.pandruvada@linux.intel.com Signed-off-by: Yu Chen yu.c.chen@intel.com [ rjw: Subject/changelog, minor modifications ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/cpufreq/intel_pstate.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -779,6 +779,8 @@ static int intel_pstate_hwp_save_state(s return 0; }
+static void intel_pstate_hwp_enable(struct cpudata *cpudata); + static int intel_pstate_resume(struct cpufreq_policy *policy) { if (!hwp_active) @@ -786,6 +788,9 @@ static int intel_pstate_resume(struct cp
mutex_lock(&intel_pstate_limits_lock);
+ if (policy->cpu == 0) + intel_pstate_hwp_enable(all_cpu_data[policy->cpu]); + all_cpu_data[policy->cpu]->epp_policy = 0; intel_pstate_hwp_set(policy->cpu);