RE: [PATCH v8 00/13] Implement AMD Pstate EPP Driver

[Yuan, Perry]

[AMD Official Use Only - General]



> -----Original Message-----
> From: Tor Vic <torvic9@xxxxxxxxxxx>
> Sent: Wednesday, December 21, 2022 2:53 AM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>; rafael.j.wysocki@xxxxxxxxx;
> Limonciello, Mario <Mario.Limonciello@xxxxxxx>; Huang, Ray
> <Ray.Huang@xxxxxxx>; viresh.kumar@xxxxxxxxxx
> Cc: Sharma, Deepak <Deepak.Sharma@xxxxxxx>; Fontenot, Nathan
> <Nathan.Fontenot@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Meng,
> Li (Jassmine) <Li.Meng@xxxxxxx>; Karny, Wyes <Wyes.Karny@xxxxxxx>;
> linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v8 00/13] Implement AMD Pstate EPP Driver
> 
> 
> On 20.12.22 18:13, Tor Vic wrote:
> >
> > On 19.12.22 06:40, Perry Yuan wrote:
> >> Hi all,
> >>
> >> This patchset implements one new AMD CPU frequency driver
> >> `amd-pstate-epp` instance for better performance and power control.
> >> CPPC has a parameter called energy preference performance (EPP).
> >> The EPP is used in the CCLK DPM controller to drive the frequency
> >> that a core is going to operate during short periods of activity.
> >> EPP values will be utilized for different OS profiles (balanced,
> >> performance, power savings).
> >>
> >
> > Using v8 and clang-15 on 6.1 I get:
> >
> 
> Got it.
> Mario was right. INTEL_PSTATE must be selected, it has become a
> dependency.
> 
> That doesn't seem correct.
> 
> With it selected, it builds just fine. Not tested though.

Yeah, I will make it in v9.
Thanks for your feedback!


> 
> > ---
> > ld.lld: error: undefined symbol: energy_perf_strings  >>> referenced
> > by amd-pstate.c:789
> > (/tmp/makepkg/linux61-vd/src/linux-stable/drivers/cpufreq/amd-pstate.c
> > :789)  >>>
> > vmlinux.o:(show_energy_performance_preference)
> >  >>> referenced by amd-pstate.c:768
> > (/tmp/makepkg/linux61-vd/src/linux-stable/drivers/cpufreq/amd-pstate.c
> > :768)  >>>
> > vmlinux.o:(store_energy_performance_preference)
> >  >>> referenced by amd-pstate.c:749
> > (/tmp/makepkg/linux61-vd/src/linux-stable/drivers/cpufreq/amd-
> pstate.c:749)
> >  >>>
> > vmlinux.o:(show_energy_performance_available_preferences)
> >  >>> referenced 1 more times
> >  >>> did you mean: energy_perf_strings  >>> defined in: vmlinux.o
> >
> > ld.lld: error: undefined symbol: epp_values  >>> referenced by
> > amd-pstate.c:189
> > (/tmp/makepkg/linux61-vd/src/linux-stable/drivers/cpufreq/amd-pstate.c
> > :189)  >>>
> > vmlinux.o:(store_energy_performance_preference)
> > ---
> >
> > and a few warnings:
> >
> > ---
> > drivers/cpufreq/amd-pstate.c:966:6: warning: variable 'ret' is used
> > uninitialized whenever 'if' condition is true
> > [-Wsometimes-uninitialized]
> >          if (rc)
> >              ^~
> > drivers/cpufreq/amd-pstate.c:1025:9: note: uninitialized use occurs
> > here
> >          return ret;
> >                 ^~~
> > drivers/cpufreq/amd-pstate.c:966:2: note: remove the 'if' if its
> > condition is always false
> >          if (rc)
> >          ^~~~~~~
> > drivers/cpufreq/amd-pstate.c:962:6: warning: variable 'ret' is used
> > uninitialized whenever 'if' condition is true
> > [-Wsometimes-uninitialized]
> >          if (!dev)
> >              ^~~~
> > drivers/cpufreq/amd-pstate.c:1025:9: note: uninitialized use occurs
> > here
> >          return ret;
> >                 ^~~
> > drivers/cpufreq/amd-pstate.c:962:2: note: remove the 'if' if its
> > condition is always false
> >          if (!dev)
> >          ^~~~~~~~~
> > drivers/cpufreq/amd-pstate.c:949:66: note: initialize the variable 'ret'
> > to silence this warning
> >          int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq,
> > ret;
> >
> > ^
> >
> >   = 0
> > drivers/cpufreq/amd-pstate.c:996:52: warning: variable 'value' is
> > uninitialized when used here [-Wuninitialized]
> >          cpudata->epp_cached = amd_pstate_get_epp(cpudata, value);
> >                                                            ^~~~~
> > drivers/cpufreq/amd-pstate.c:953:11: note: initialize the variable
> > 'value' to silence this warning
> >          u64 value;
> >                   ^
> >                    = 0
> > drivers/cpufreq/amd-pstate.c:1085:6: warning: variable 'epp' is used
> > uninitialized whenever 'if' condition is true
> > [-Wsometimes-uninitialized]
> >          if (cpudata->epp_policy == cpudata->policy)
> >              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > drivers/cpufreq/amd-pstate.c:1110:30: note: uninitialized use occurs
> > here
> >          amd_pstate_set_epp(cpudata, epp);
> >                                      ^~~
> > drivers/cpufreq/amd-pstate.c:1085:2: note: remove the 'if' if its
> > condition is always false
> >          if (cpudata->epp_policy == cpudata->policy)
> >          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > drivers/cpufreq/amd-pstate.c:1064:9: note: initialize the variable 'epp'
> > to silence this warning
> >          s16 epp;
> >                 ^
> >                  = 0
> > ---
> >
> > Cheers,
> >
> > Tor Vic
> >