linux-kernel - [PATCH v11 09/11] Documentation: introduce amd pstate active mode kernel command line options

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Message-ID: <20230118075210.447418-10-perry.yuan@amd.com>
Date:   Wed, 18 Jan 2023 15:52:08 +0800
From:   Perry Yuan <perry.yuan@....com>
To:     <rafael.j.wysocki@...el.com>, <Mario.Limonciello@....com>,
        <ray.huang@....com>, <viresh.kumar@...aro.org>
CC:     <Deepak.Sharma@....com>, <Nathan.Fontenot@....com>,
        <Alexander.Deucher@....com>, <Shimmer.Huang@....com>,
        <Xiaojian.Du@....com>, <Li.Meng@....com>, <wyes.karny@....com>,
        <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v11 09/11] Documentation: introduce amd pstate active mode kernel command line options

AMD Pstate driver support another firmware based autonomous mode
with "amd_pstate=active" added to the kernel command line.
In autonomous mode SMU firmware decides frequencies at runtime
based on workload utilization, usage in other IPs, infrastructure
limits such as power, thermals and so on.

Acked-by: Huang Rui <ray.huang@....com>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>
Tested-by: Wyes Karny <wyes.karny@....com>
Signed-off-by: Perry Yuan <perry.yuan@....com>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6cfa6e3996cf..e3618dfdb36a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7020,3 +7020,10 @@
 			  management firmware translates the requests into actual
 			  hardware states (core frequency, data fabric and memory
 			  clocks etc.)
+			active
+			  Use amd_pstate_epp driver instance as the scaling driver,
+			  driver provides a hint to the hardware if software wants
+			  to bias toward performance (0x0) or energy efficiency (0xff)
+			  to the CPPC firmware. then CPPC power algorithm will
+			  calculate the runtime workload and adjust the realtime cores
+			  frequency.
-- 
2.34.1