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

[Tor Vic]

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:

---
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