| Message ID | 20201217104215.2544837-1-srinivas.pandruvada@linux.intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | cpufreq: intel_pstate: Use the latest guaranteed freq during verify | expand |
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 2a4db856222f..7081d1edb22b 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2199,6 +2199,12 @@ static void intel_pstate_clear_update_util_hook(unsigned int cpu) static int intel_pstate_get_max_freq(struct cpudata *cpu) { + if (hwp_active) { + int turbo_max, max_state; + + intel_pstate_get_hwp_max(cpu->cpu, &turbo_max, &max_state); + return max_state * cpu->pstate.scaling; + } return global.turbo_disabled || global.no_turbo ? cpu->pstate.max_freq : cpu->pstate.turbo_freq; }
This change tries to address an issue, when BIOS disabled turbo but HWP_CAP guaranteed is changed later and user space wants to take advantage of this increased guaranteed performance. The HWP_CAP.GUARANTEED value is not a static value. It can be changed by some out of band agent or during Intel Speed Select performance level change. The HWP_CAP.MAX still shows max possible performance when BIOS disabled turbo. So guaranteed can still change as long as this is same or below HWP_CAP.MAX. When guaranteed is changed, the sysfs base_frequency attributes shows the latest guaranteed frequency. This attribute can be used by user space software to update scaling min/max frequency. Currently the setpolicy callback already uses the latest HWP_CAP values when setting HWP_REQ. But the verify callback will still restrict the user settings to the to old guaranteed value. So if the guaranteed is increased, user space can't take advantage of it. To solve this similar to setpolicy callback, read the latest HWP_CAP values and use it to restrict the maximum setting. This is done by calling intel_pstate_get_hwp_max(), which already accounts for user and BIOS turbo disable to get the current max performance. This issue is side effect of fixing the issue of scaling frequency limits by the 'commit eacc9c5a927e ("cpufreq: intel_pstate: Fix intel_pstate_get_hwp_max() for turbo disabled")' The fix resulted in correct setting of reduced scaling frequencies, but this resulted in capping HWP.REQ to HWP_CAP.GUARANTEED in this case. Cc: 5.8+ <stable@vger.kernel.org> # 5.8+ Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> --- drivers/cpufreq/intel_pstate.c | 6 ++++++ 1 file changed, 6 insertions(+)