Re: [PATCH 2/7] cpufreq: amd_pstate: add module parameter to load amd pstate EPP driver

From: Limonciello, Mario
Date: Fri Sep 09 2022 - 14:49:56 EST


On 9/9/2022 11:45, Perry Yuan wrote:
The amd_pstate mode parameter will allow user to select which amd pstate
working mode as booting mode, amd_pstate instance or amd_pstate_epp instance.

1) amd_pstate instance is depending on the target operation mode.
2) amd_pstate_epp instance is depending on the set_policy operation mode.It
is also called active mode that AMD SMU has EPP algorithm to control the
CPU runtime frequency according to the EPP set value and workload.

Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
---
drivers/cpufreq/amd-pstate.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index a2463f785322..451295284a26 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -58,6 +58,12 @@ module_param(shared_mem, bool, 0444);
MODULE_PARM_DESC(shared_mem,
"enable amd-pstate on processors with shared memory solution (false = disabled (default), true = enabled)");
+static bool epp_enabled = true;
+module_param(epp_enabled, bool, 0444);
+MODULE_PARM_DESC(epp_enabled,
+ "load amd_pstate or amd_pstate_epp (true = amd_pstate_epp driver instance (default), false = amd_pstate driver instance)");
+

If you're operating in EPP mode or not the kernel module is still 'amd-pstate'. So to a user I think this is a pretty confusing designation.

I would propose the following instead:

> +static bool epp = true;
> +module_param(epp, bool, 0444);
> +MODULE_PARM_DESC(epp,
> + "Enable energy performance preference (EPP) control");

+
static struct cpufreq_driver amd_pstate_driver;
/**