| Message ID | 20241024022952.2627694-1-liwei728@huawei.com (mailing list archive) |
|---|---|
| State | Queued |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | [v3] cpufreq/cppc: fix perf_to_khz/khz_to_perf conversion exception | expand |
On Thu, Oct 24, 2024 at 4:16 AM liwei <liwei728@huawei.com> wrote: > > When the nominal_freq recorded by the kernel is equal to the lowest_freq, > and the frequency adjustment operation is triggered externally, there is > a logic error in cppc_perf_to_khz()/cppc_khz_to_perf(), resulting in perf > and khz conversion errors. > > Fix this by adding the branch processing logic when nominal_freq is equal > to lowest_freq. > > Fixes: ec1c7ad47664 ("cpufreq: CPPC: Fix performance/frequency conversion") > Signed-off-by: liwei <liwei728@huawei.com> > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > v2: > - Fix similar issue in cppc_khz_to_perf() > --- > v3: > - Add acked-by tag > --- > drivers/acpi/cppc_acpi.c | 22 +++++++++++++++++----- > 1 file changed, 17 insertions(+), 5 deletions(-) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c > index b73b3aa92f3f..c3fc2c05d868 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -1916,9 +1916,15 @@ unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf) > u64 mul, div; > > if (caps->lowest_freq && caps->nominal_freq) { > - mul = caps->nominal_freq - caps->lowest_freq; > + /* Avoid special case when nominal_freq is equal to lowest_freq */ > + if (caps->lowest_freq == caps->nominal_freq) { > + mul = caps->nominal_freq; > + div = caps->nominal_perf; > + } else { > + mul = caps->nominal_freq - caps->lowest_freq; > + div = caps->nominal_perf - caps->lowest_perf; > + } > mul *= KHZ_PER_MHZ; > - div = caps->nominal_perf - caps->lowest_perf; > offset = caps->nominal_freq * KHZ_PER_MHZ - > div64_u64(caps->nominal_perf * mul, div); > } else { > @@ -1939,11 +1945,17 @@ unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq) > { > s64 retval, offset = 0; > static u64 max_khz; > - u64 mul, div; > + u64 mul, div; > > if (caps->lowest_freq && caps->nominal_freq) { > - mul = caps->nominal_perf - caps->lowest_perf; > - div = caps->nominal_freq - caps->lowest_freq; > + /* Avoid special case when nominal_freq is equal to lowest_freq */ > + if (caps->lowest_freq == caps->nominal_freq) { > + mul = caps->nominal_perf; > + div = caps->nominal_freq; > + } else { > + mul = caps->nominal_perf - caps->lowest_perf; > + div = caps->nominal_freq - caps->lowest_freq; > + } > /* > * We don't need to convert to kHz for computing offset and can > * directly use nominal_freq and lowest_freq as the div64_u64 > -- Applied as 6.12-rc material, thanks!
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index b73b3aa92f3f..c3fc2c05d868 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1916,9 +1916,15 @@ unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf) u64 mul, div; if (caps->lowest_freq && caps->nominal_freq) { - mul = caps->nominal_freq - caps->lowest_freq; + /* Avoid special case when nominal_freq is equal to lowest_freq */ + if (caps->lowest_freq == caps->nominal_freq) { + mul = caps->nominal_freq; + div = caps->nominal_perf; + } else { + mul = caps->nominal_freq - caps->lowest_freq; + div = caps->nominal_perf - caps->lowest_perf; + } mul *= KHZ_PER_MHZ; - div = caps->nominal_perf - caps->lowest_perf; offset = caps->nominal_freq * KHZ_PER_MHZ - div64_u64(caps->nominal_perf * mul, div); } else { @@ -1939,11 +1945,17 @@ unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq) { s64 retval, offset = 0; static u64 max_khz; - u64 mul, div; + u64 mul, div; if (caps->lowest_freq && caps->nominal_freq) { - mul = caps->nominal_perf - caps->lowest_perf; - div = caps->nominal_freq - caps->lowest_freq; + /* Avoid special case when nominal_freq is equal to lowest_freq */ + if (caps->lowest_freq == caps->nominal_freq) { + mul = caps->nominal_perf; + div = caps->nominal_freq; + } else { + mul = caps->nominal_perf - caps->lowest_perf; + div = caps->nominal_freq - caps->lowest_freq; + } /* * We don't need to convert to kHz for computing offset and can * directly use nominal_freq and lowest_freq as the div64_u64
When the nominal_freq recorded by the kernel is equal to the lowest_freq, and the frequency adjustment operation is triggered externally, there is a logic error in cppc_perf_to_khz()/cppc_khz_to_perf(), resulting in perf and khz conversion errors. Fix this by adding the branch processing logic when nominal_freq is equal to lowest_freq. Fixes: ec1c7ad47664 ("cpufreq: CPPC: Fix performance/frequency conversion") Signed-off-by: liwei <liwei728@huawei.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> --- v2: - Fix similar issue in cppc_khz_to_perf() --- v3: - Add acked-by tag --- drivers/acpi/cppc_acpi.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-)