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The cppc-cpufreq > target callbacks nevertheless populate both values for every request > without checking whether the controls are implemented. > > cppc_set_perf() consequently passes a NULL register descriptor to > cpc_write(). The write fails width validation and its return value is > ignored, so the failed access path is repeated on every target request. > > Check that each optional limit control is supported before calling > cpc_write(). Looks good. DESIRED_PERF is also optional when CPPC2 and autonomous selection are enabled. Should its write also be guarded with CPC_SUPPORTED()? Reviewed-by: Sumit Gupta > > Fixes: ea3db45ae476 ("cpufreq: cppc: Update MIN_PERF/MAX_PERF in target callbacks") > Signed-off-by: Christian Loehle > --- > drivers/acpi/cppc_acpi.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c > index 1d3a94100491..7bac6d5da24b 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -1970,9 +1970,9 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) > * value to min and max perf, but they don't mean to set the zero value, > * they just don't want to write to those registers. > */ > - if (perf_ctrls->min_perf) > + if (perf_ctrls->min_perf && CPC_SUPPORTED(min_perf_reg)) > cpc_write(cpu, min_perf_reg, perf_ctrls->min_perf); > - if (perf_ctrls->max_perf) > + if (perf_ctrls->max_perf && CPC_SUPPORTED(max_perf_reg)) > cpc_write(cpu, max_perf_reg, perf_ctrls->max_perf); > > if (CPC_IN_PCC(desired_reg) || CPC_IN_PCC(min_perf_reg) || CPC_IN_PCC(max_perf_reg)) > -- > 2.34.1 >