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authorSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>2023-09-07 11:02:07 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-09-11 20:18:17 +0200
commit37b6ddba967c601479bea418a7ac6ff16b6232b7 (patch)
tree08fdb8b26e70cb8aa70b01372af04d96d78f675e /drivers/cpufreq/intel_pstate.c
parent0bb80ecc33a8fb5a682236443c1e740d5c917d1d (diff)
cpufreq: intel_pstate: Revise global turbo disable check
Setting global turbo flag based on CPU 0 P-state limits is problematic as it limits max P-state request on every CPU on the system just based on its P-state limits. There are two cases in which global.turbo_disabled flag is set: - When the MSR_IA32_MISC_ENABLE_TURBO_DISABLE bit is set to 1 in the MSR MSR_IA32_MISC_ENABLE. This bit can be only changed by the system BIOS before power up. - When the max non turbo P-state is same as max turbo P-state for CPU 0. The second check is not a valid to decide global turbo state based on the CPU 0. CPU 0 max turbo P-state can be same as max non turbo P-state, but for other CPUs this may not be true. There is no guarantee that max P-state limits are same for every CPU. This is possible that during fusing max P-state for a CPU is constrained. Also with the Intel Speed Select performance profile, CPU 0 may not be present in all profiles. In this case the max non turbo and turbo P-state can be set to the lowest possible P-state by the hardware when switched to such profile. Since max non turbo and turbo P-state is same, global.turbo_disabled flag will be set. Once global.turbo_disabled is set, any scaling max and min frequency update for any CPU will result in its max P-state constrained to the max non turbo P-state. Hence remove the check of max non turbo P-state equal to max turbo P-state of CPU 0 to set global turbo disabled flag. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> [ rjw: Subject edit ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/intel_pstate.c')
-rw-r--r--drivers/cpufreq/intel_pstate.c6
1 files changed, 1 insertions, 5 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index dc50c9fb488d..a534a1f7f1ee 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -571,13 +571,9 @@ static void intel_pstate_hybrid_hwp_adjust(struct cpudata *cpu)
static inline void update_turbo_state(void)
{
u64 misc_en;
- struct cpudata *cpu;
- cpu = all_cpu_data[0];
rdmsrl(MSR_IA32_MISC_ENABLE, misc_en);
- global.turbo_disabled =
- (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE ||
- cpu->pstate.max_pstate == cpu->pstate.turbo_pstate);
+ global.turbo_disabled = misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
}
static int min_perf_pct_min(void)