Hello Liwei, Thanks for the fix. I think there might be a similar issue in cppc_khz_to_perf(), Regards, Pierre On 4/30/24 12:12, liwei wrote:
When the nominal_freq recorded by the kernel is equal to lowest_freq and the frequency reduction operation is triggered externally, there is a conversion logic error in cppc_perf_to_khz(), causing the kernel to be unable to feedback the true frequency. 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@xxxxxxxxxx> --- drivers/acpi/cppc_acpi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index a40b6f3946ef..92aac6974e0e 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1869,9 +1869,15 @@ 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 the 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 {
