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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-10-23 18:35:32 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-10-27 20:53:35 +0300
commite0be38ed4ab413ddd492118cf146369b86ee0ab5 (patch)
tree9a504b819de68d464cb62c1529eef15e7510946c /drivers/cpufreq
parent1c534352f47fd83eb08075ac2474f707e74bf7f7 (diff)
downloadlinux-e0be38ed4ab413ddd492118cf146369b86ee0ab5.tar.xz
cpufreq: intel_pstate: Avoid missing HWP max updates in passive mode
If the cpufreq policy max limit is changed when intel_pstate operates in the passive mode with HWP enabled and the "powersave" governor is used on top of it, the HWP max limit is not updated as appropriate. Namely, in the "powersave" governor case, the target P-state is always equal to the policy min limit, so if the latter does not change, intel_cpufreq_adjust_hwp() is not invoked to update the HWP Request MSR due to the "target_pstate != old_pstate" check in intel_cpufreq_update_pstate(), so the HWP max limit is not updated as a result. Also, if the CPUFREQ_NEED_UPDATE_LIMITS flag is not set for the driver and the target frequency does not change along with the policy max limit, the "target_freq == policy->cur" check in __cpufreq_driver_target() prevents the driver's ->target() callback from being invoked at all, so the HWP max limit is not updated. To prevent that occurring, set the CPUFREQ_NEED_UPDATE_LIMITS flag in the intel_cpufreq driver structure if HWP is enabled and modify intel_cpufreq_update_pstate() to do the "target_pstate != old_pstate" check only in the non-HWP case and let intel_cpufreq_adjust_hwp() always run in the HWP case (it will update HWP Request only if the cached value of the register is different from the new one including the limits, so if neither the target P-state value nor the max limit changes, the register write will still be avoided). Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled") Reported-by: Zhang Rui <rui.zhang@intel.com> Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: 1c534352f47f cpufreq: Introduce CPUFREQ_NEED_UPDATE_LIMITS ... Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Tested-by: Zhang Rui <rui.zhang@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/intel_pstate.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 3c1455518738..b7a9779250aa 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -2568,14 +2568,12 @@ static int intel_cpufreq_update_pstate(struct cpudata *cpu, int target_pstate,
int old_pstate = cpu->pstate.current_pstate;
target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
- if (target_pstate != old_pstate) {
+ if (hwp_active) {
+ intel_cpufreq_adjust_hwp(cpu, target_pstate, fast_switch);
+ cpu->pstate.current_pstate = target_pstate;
+ } else if (target_pstate != old_pstate) {
+ intel_cpufreq_adjust_perf_ctl(cpu, target_pstate, fast_switch);
cpu->pstate.current_pstate = target_pstate;
- if (hwp_active)
- intel_cpufreq_adjust_hwp(cpu, target_pstate,
- fast_switch);
- else
- intel_cpufreq_adjust_perf_ctl(cpu, target_pstate,
- fast_switch);
}
intel_cpufreq_trace(cpu, fast_switch ? INTEL_PSTATE_TRACE_FAST_SWITCH :
@@ -3032,6 +3030,7 @@ static int __init intel_pstate_init(void)
hwp_mode_bdw = id->driver_data;
intel_pstate.attr = hwp_cpufreq_attrs;
intel_cpufreq.attr = hwp_cpufreq_attrs;
+ intel_cpufreq.flags |= CPUFREQ_NEED_UPDATE_LIMITS;
if (!default_driver)
default_driver = &intel_pstate;