FIE assumes the delivered/relative perf registers are fast to read so it goes ahead and hits them quite frequently. On a couple Arm platforms though they end up in PCC regions which require mailbox handshaking with other parts of the platform. This results in a lot of overhead in the cppc_fie task. As such lets runtime disable FIE if we detect it enabled on one of those platforms. Also allow the user to manually disable it via a module parameter. v1->v2: Apply Rafael's review comments. Move the MODULE_PARAM into the ifdef Fix compiler warning when ACPI_CPPC_LIB is disabled. Jeremy Linton (1): ACPI: CPPC: Disable FIE if registers in PCC regions drivers/acpi/cppc_acpi.c | 41 ++++++++++++++++++++++++++++++++++ drivers/cpufreq/cppc_cpufreq.c | 19 ++++++++++++---- include/acpi/cppc_acpi.h | 5 +++++ 3 files changed, 61 insertions(+), 4 deletions(-) -- 2.35.3
