From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
If turbo P-states cannot be used, either due to the configuration of
the processor, or because intel_pstate is not allowed to used them,
the maximum available P-state with HWP enabled corresponds to the
HWP_CAP.GUARANTEED value which is not static. It can be adjusted by
an out-of-band agent or during an Intel Speed Select performance
level change, so long as it remains less than or equal to
HWP_CAP.MAX.
However, if turbo P-states cannot be used, intel_cpufreq_adjust_perf()
always uses pstate.max_pstate (set during the initialization of the
driver only) as the maximum available P-state, so it may miss a change
of the HWP_CAP.GUARANTEED value.
Prevent that from happening by modifyig intel_cpufreq_adjust_perf()
to always read the "guaranteed" and "maximum turbo" performance
levels from the cached HWP_CAP value.
Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
---
drivers/cpufreq/intel_pstate.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -2653,12 +2653,13 @@ static void intel_cpufreq_adjust_perf(un
unsigned long capacity)
{
struct cpudata *cpu = all_cpu_data[cpunum];
+ u64 hwp_cap = READ_ONCE(cpu->hwp_cap_cached);
int old_pstate = cpu->pstate.current_pstate;
int cap_pstate, min_pstate, max_pstate, target_pstate;
update_turbo_state();
- cap_pstate = global.turbo_disabled ? cpu->pstate.max_pstate :
- cpu->pstate.turbo_pstate;
+ cap_pstate = global.turbo_disabled ? HWP_GUARANTEED_PERF(hwp_cap) :
+ HWP_HIGHEST_PERF(hwp_cap);
/* Optimization: Avoid unnecessary divisions. */
