Messages in this thread | | | From | Doug Smythies <> | Date | Thu, 9 Sep 2021 06:30:23 -0700 | Subject | Re: [PATCH] cpufreq: intel_pstate: Override parameters if HWP forced by BIOS |
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On Wed, Sep 8, 2021 at 11:33 PM Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> wrote: > > On Wed, 2021-09-08 at 20:48 -0700, Doug Smythies wrote: > > If HWP has been already been enabled by BIOS, it may be > > necessary to override some kernel command line parameters. > > Once it has been enabled it requires a reset to be disabled. > > > > Signed-off-by: Doug Smythies <dsmythies@telus.net> > > --- > > drivers/cpufreq/intel_pstate.c | 22 ++++++++++++++++------ > > 1 file changed, 16 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/cpufreq/intel_pstate.c > > b/drivers/cpufreq/intel_pstate.c > > index bb4549959b11..073bae5d4498 100644 > > --- a/drivers/cpufreq/intel_pstate.c > > +++ b/drivers/cpufreq/intel_pstate.c > > @@ -3267,7 +3267,7 @@ static int __init intel_pstate_init(void) > > */ > > if ((!no_hwp && boot_cpu_has(X86_FEATURE_HWP_EPP)) || > > intel_pstate_hwp_is_enabled()) { > > - hwp_active++; > > + hwp_active = 1; > Why this change?
It was just to keep it at 1, but I agree not absolutely needed.
> > > hwp_mode_bdw = id->driver_data; > > intel_pstate.attr = hwp_cpufreq_attrs; > > intel_cpufreq.attr = hwp_cpufreq_attrs; > > @@ -3347,17 +3347,27 @@ device_initcall(intel_pstate_init); > > > > static int __init intel_pstate_setup(char *str) > > { > > + /* > > + * If BIOS is forcing HWP, then parameter > > + * overrides might be needed. Only print > > + * the message once, and regardless of > > + * any overrides. > > + */ > > + if(!hwp_active > This part of code is from early_param, Is it possible that > hwp_active is not 0?
Not at this point, in any testing I did. But I do not know the authoritative answer to your question.
> > > && boot_cpu_has(X86_FEATURE_HWP)) > > + if(intel_pstate_hwp_is_enabled()){ > > + pr_info("HWP enabled by BIOS\n"); > > + hwp_active = 1; > > + } > > if (!str) > > return -EINVAL; > > > > - if (!strcmp(str, "disable")) > > + if (!strcmp(str, "disable") && !hwp_active) > > no_load = 1; > > - else if (!strcmp(str, "active")) > > + if (!strcmp(str, "active")) > > default_driver = &intel_pstate; > > - else if (!strcmp(str, "passive")) > > + if (!strcmp(str, "passive")) > > default_driver = &intel_cpufreq; > > Why "else if" changed to "if" ?
Because it doesn't matter anyway and I would have had to figure out another qualifier. This way, and given that this executes once per intel_pstate command line parameter, the code executes the way it used to, overall.
> > > Thanks, > Srinivas > > > - > > - if (!strcmp(str, "no_hwp")) { > > + if (!strcmp(str, "no_hwp") && !hwp_active) { > > pr_info("HWP disabled\n"); > > no_hwp = 1; > > } > >
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