Re: [PATCH 1/3] cpupower: Add generic CPPC performance display

[Jeremy Linton <jeremy.linton@arm.com>]

Hi,

On 7/18/26 1:12 AM, Thorsten Leemhuis wrote:
> On 7/10/26 00:13, Jeremy Linton wrote:
>> Arm64 machines, and possibly others, use the standard ACPI defined CPPC
>> infrastructure. cpupower has CPPC support, but it's largely written
>> around the intricacies of AMD processors, using platform MSRs to avoid
>> shortcomings in the specification.

Patch to fix it.

https://lkml.org/lkml/2026/7/20/2191

>>
>> [...]
>> +#include <stdio.h>
>> +#include <errno.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <math.h>
>> +
>> +#include "helpers/helpers.h"
>> +#include "cpufreq.h"
>> +#include "acpi_cppc.h"
>> +
>> +#define cppc_to_frequency(perf) (roundf(slope * (perf) + intercept))
> FYI, this patch showed up in -next yesterday and I suspect it caused
> this build error for me on x86_64:
> 
> """  CC       cpupower
> /usr/bin/ld.bfd: /tmp/ccjOeWLF.ltrans0.ltrans.o: in function
> `get_perf_cap.isra.0':
> /builddir/build/BUILD/kernel-7.2.0-build/kernel-next-20260717/linux-7.2.0-0.0.next.20260717.330.vanilla.fc44.x86_64/tools/power/cpupower/utils/helpers/cppc.c:39:(.text+0x45cc):
> undefined reference to `roundf'
> /usr/bin/ld.bfd:
> /tmp/ccjOeWLF.ltrans0.ltrans.o:/builddir/build/BUILD/kernel-7.2.0-build/kernel-next-20260717/linux-7.2.0-0.0.next.20260717.330.vanilla.fc44.x86_64/tools/power/cpupower/utils/helpers/cppc.c:49:(.text+0x46a2):
> undefined reference to `roundf'
> collect2: error: ld returned 1 exit status
> make: *** [Makefile:238: cpupower] Error 1
> """
>> [...]
> 
> Full log:
> https://download.copr.fedorainfracloud.org/results/@kernel-vanilla/next/fedora-44-x86_64/10739303-next-next-all/builder-live.log.gz
> 
> Ciao, Thorsten