Messages in this thread | | | Subject | Re: [PATCH] Revert "cpufreq: intel_pstate: Fix ->set_policy() interface for no_turbo" | From | Gabriele Mazzotta <> | Date | Sat, 4 Aug 2018 19:31:50 +0200 |
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On 04/08/2018 17:29, Gabriele Mazzotta wrote: > This change does not take into account that some BIOSes change > MSR_IA32_MISC_ENABLE_TURBO_DISABLE depending on the power source. > If the turbo is disabled when the system boots, policy.max_freq > is set to pstate.max_pstate. However, if the BIOS later enables > the turbo, the CPU will never be able to run at pstate.turbo_pstate. > > Since now intel_pstate_set_policy() does its calculations using > pstate.max_freq and pstate.turbo_freq, we can always calculate > cpuinfo.max_freq using pstate.turbo_pstate, thus allowing system > with varying MSR_IA32_MISC_ENABLE_TURBO_DISABLE to run at full > speed when the turbo is enabled. > > This reverts commit 983e600e88835f0321d1a0ea06f52d48b7b5a544. > > Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com> > --- > drivers/cpufreq/intel_pstate.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 3c3971256130..4043aae2d611 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -2068,9 +2068,8 @@ 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; > update_turbo_state();
Commit 983e600e8883 added this update_turbo_state() call, but it is needed by intel_pstate_init_acpi_perf_limits() here below. I should have mentioned it in the commit message.
However, I've just realized that a similar problem to that I'm trying to fix can occur on those systems where core_frequency is adjusted depending on the availability of the turbo.
The call to update_turbo_state() could also be moved in intel_pstate_init_acpi_perf_limits(), right before the check on global.turbo_disabled.
> - policy->cpuinfo.max_freq = global.turbo_disabled ? > - cpu->pstate.max_pstate : cpu->pstate.turbo_pstate; > - policy->cpuinfo.max_freq *= cpu->pstate.scaling; > + policy->cpuinfo.max_freq = > + cpu->pstate.turbo_pstate * cpu->pstate.scaling; > > intel_pstate_init_acpi_perf_limits(policy); > >
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