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cpufreq: intel_pstate: Use HWP capabilities in intel_cpufreq_adjust_perf()

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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.

Fixes: a365ab6b9d ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
This commit is contained in:
Rafael J. Wysocki 2021-01-05 19:20:29 +01:00
parent e71ba9452f
commit 17ffd35809
1 changed files with 3 additions and 2 deletions
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5
drivers/cpufreq/intel_pstate.c
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@ -2653,12 +2653,13 @@ static void intel_cpufreq_adjust_perf(unsigned int cpunum,
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. */