The power library does not work with the amd-pstate driver in passive mode. Initialization fails because the current frequency read from scaling_setspeed never matches one of the synthesized frequency buckets exactly, since amd-pstate scales continuously.
The first patch fixes the matching. The second fixes an unrelated bug found while testing: the sysfs file is buffered, so a frequency the kernel rejected was reported as success. The third fixes the unit test, which assumed the nominal frequency sits at a fixed index in the table. Tested on a Ryzen 9 7945HX booted with amd_pstate=passive and the cpufreq_userspace governor loaded. power_cpufreq_autotest now passes, with and without turbo. v2 - fixed review comment from GPT - fixed two other bugs found during review/testing. Stephen Hemminger (3): power/amd_pstate: fix frequency matching for continuous scaling power: check for errors when writing frequency test/power: fix nominal frequency check with amd-pstate app/test/test_power_cpufreq.c | 5 +- drivers/power/acpi/acpi_cpufreq.c | 12 ++- drivers/power/amd_pstate/amd_pstate_cpufreq.c | 89 +++++++++++++------ drivers/power/cppc/cppc_cpufreq.c | 12 ++- 4 files changed, 74 insertions(+), 44 deletions(-) -- 2.53.0
