Commit 217e6778 authored by Wyes Karny's avatar Wyes Karny Committed by Rafael J. Wysocki
Browse files

cpufreq: amd-pstate: Write CPPC enable bit per-socket 



Currently amd_pstate sets CPPC enable bit in MSR_AMD_CPPC_ENABLE only
for the CPU where the module_init happened. But MSR_AMD_CPPC_ENABLE is
per-socket. This causes CPPC enable bit to set for only one socket for
servers with more than one physical packages. To fix this write
MSR_AMD_CPPC_ENABLE per-socket.

Also, handle duplicate calls for cppc_enable, because it's called from
per-policy/per-core callbacks and can result in duplicate MSR writes.

Before the fix:
amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
	192 0
    192 1

After the fix:
amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
    384 1

Suggested-by: default avatarGautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: default avatarWyes Karny <wyes.karny@amd.com>
Acked-by: default avatarHuang Rui <ray.huang@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent b4a11fa3

drivers/cpufreq/amd-pstate.c

+27 −1
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ static struct cpufreq_driver *current_pstate_driver; 
static struct cpufreq_driver amd_pstate_driver;

static struct cpufreq_driver amd_pstate_epp_driver;

static int cppc_state = AMD_PSTATE_DISABLE;

static bool cppc_enabled;



/*

 * AMD Energy Preference Performance (EPP)
@@ -228,7 +229,28 @@ static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata, 


static inline int pstate_enable(bool enable)

{

	return wrmsrl_safe(MSR_AMD_CPPC_ENABLE, enable);

	int ret, cpu;

	unsigned long logical_proc_id_mask = 0;



	if (enable == cppc_enabled)

		return 0;



	for_each_present_cpu(cpu) {

		unsigned long logical_id = topology_logical_die_id(cpu);



		if (test_bit(logical_id, &logical_proc_id_mask))

			continue;



		set_bit(logical_id, &logical_proc_id_mask);



		ret = wrmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_ENABLE,

				enable);

		if (ret)

			return ret;

	}



	cppc_enabled = enable;

	return 0;

}



static int cppc_enable(bool enable)
@@ -236,6 +258,9 @@ static int cppc_enable(bool enable) 
	int cpu, ret = 0;

	struct cppc_perf_ctrls perf_ctrls;



	if (enable == cppc_enabled)

		return 0;



	for_each_present_cpu(cpu) {

		ret = cppc_set_enable(cpu, enable);

		if (ret)
@@ -251,6 +276,7 @@ static int cppc_enable(bool enable) 
		}

	}



	cppc_enabled = enable;

	return ret;

}