cpufreq: amd-pstate: Fix initial highest_perf value
authorPerry Yuan <Perry.Yuan@amd.com>
Tue, 30 Aug 2022 01:56:00 +0000 (09:56 +0800)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Sat, 3 Sep 2022 18:17:32 +0000 (20:17 +0200)
commitbedadcfb011fef55273bd686e8893fdd8911dcdb
treec1d178250aaa95bb15ec7297d6e7b68b7858155c
parentca08e46d4215e85eb3cef2481255431d98da56da
cpufreq: amd-pstate: Fix initial highest_perf value

To avoid some new AMD processors use wrong highest perf when amd pstate
driver loaded, this fix will query the highest perf from MSR register
MSR_AMD_CPPC_CAP1 and cppc_acpi interface firstly, then compare with the
highest perf value got by calling amd_get_highest_perf() function.

The lower value will be the correct highest perf we need to use.
Otherwise the CPU max MHz will be incorrect if the
amd_get_highest_perf() did not cover the new process family and model ID.

Like this lscpu info, the max frequency is incorrect.

Vendor ID:               AuthenticAMD
    Socket(s):           1
    Stepping:            2
    CPU max MHz:         5410.0000
    CPU min MHz:         400.0000
    BogoMIPS:            5600.54

Fixes: 3743d55b289c2 (x86, sched: Fix the AMD CPPC maximum performance value on certain AMD Ryzen generations)
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/cpufreq/amd-pstate.c