From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 983e600e88835f0321d1a0ea06f52d48b7b5a544 ]
When turbo is disabled, the ->set_policy() interface is broken.
For example, when turbo is disabled and cpuinfo.max = 2900000 (full
max turbo frequency), setting the limits results in frequency less
than the requested one:
Set 1000000 KHz results in 0700000 KHz
Set 1500000 KHz results in 1100000 KHz
Set 2000000 KHz results in 1500000 KHz
This is because the limits->max_perf fraction is calculated using
the max turbo frequency as the reference, but when the max P-State is
capped in intel_pstate_get_min_max(), the reference is not the max
turbo P-State. This results in reducing max P-State.
One option is to always use max turbo as reference for calculating
limits. But this will not be correct. By definition the intel_pstate
sysfs limits, shows percentage of available performance. So when
BIOS has disabled turbo, the available performance is max non turbo.
So the max_perf_pct should still show 100%.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw : Subject & changelog, rewrite in fewer lines of code ]
Cc: All applicable <redacted>
Signed-off-by: Rafael J. Wysocki <redacted>
Signed-off-by: Sasha Levin <redacted>
---
drivers/cpufreq/intel_pstate.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 1ee2ab5..e6eed20 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -1037,8 +1037,11 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
/* cpuinfo and default policy values */
policy->cpuinfo.min_freq = cpu->pstate.min_pstate * cpu->pstate.scaling;
- policy->cpuinfo.max_freq =
- cpu->pstate.turbo_pstate * cpu->pstate.scaling;
+ update_turbo_state();
+ policy->cpuinfo.max_freq = limits.turbo_disabled ?
+ cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
+ policy->cpuinfo.max_freq *= cpu->pstate.scaling;
+
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
cpumask_set_cpu(policy->cpu, policy->cpus);
--
2.5.0