Commit bedadcfb authored by Perry Yuan's avatar Perry Yuan Committed by Rafael J. Wysocki
Browse files

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: 3743d55b (x86, sched: Fix the AMD CPPC maximum performance value on certain AMD Ryzen generations)
Acked-by: default avatarHuang Rui <ray.huang@amd.com>
Signed-off-by: default avatarPerry Yuan <Perry.Yuan@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent ca08e46d

drivers/cpufreq/amd-pstate.c

+12 −2
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ static inline int amd_pstate_enable(bool enable) 
static int pstate_init_perf(struct amd_cpudata *cpudata)

{

	u64 cap1;

	u32 highest_perf;



	int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,

				     &cap1);
@@ -163,7 +164,11 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) 
	 *

	 * CPPC entry doesn't indicate the highest performance in some ASICs.

	 */

	WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());

	highest_perf = amd_get_highest_perf();

	if (highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))

		highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);



	WRITE_ONCE(cpudata->highest_perf, highest_perf);



	WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));

	WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
@@ -175,12 +180,17 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) 
static int cppc_init_perf(struct amd_cpudata *cpudata)

{

	struct cppc_perf_caps cppc_perf;

	u32 highest_perf;



	int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);

	if (ret)

		return ret;



	WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());

	highest_perf = amd_get_highest_perf();

	if (highest_perf > cppc_perf.highest_perf)

		highest_perf = cppc_perf.highest_perf;



	WRITE_ONCE(cpudata->highest_perf, highest_perf);



	WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);

	WRITE_ONCE(cpudata->lowest_nonlinear_perf,