Messages in this thread | | | Subject | Re: [PATCH] cpufreq: intel_pstate: Override parameters if HWP forced by BIOS | From | Srinivas Pandruvada <> | Date | Thu, 09 Sep 2021 07:52:54 -0700 |
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On Thu, 2021-09-09 at 06:30 -0700, Doug Smythies wrote: > 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. > But as you explained you want to prevent repeated print of "HWP enabled by BIOS". So you need this.
> > > > > && 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. If someone specified intel_pstate=active, it will also compare with "passive" with this change.
Thanks, Srinivas
> > > > > > > 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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