[PATCH 8/8] Documentation: add amd-pstate kernel command line options

[Paolo Pisati]

From: Perry Yuan <Perry.Yuan at amd.com>

BugLink: https://bugs.launchpad.net/bugs/1998106

Add a new amd pstate driver command line option to enable driver passive
working mode via MSR and shared memory interface to request desired
performance within abstract scale and the power management firmware
(SMU) convert the perf requests into actual hardware pstates.

Also the `disable` parameter can disable the pstate driver loading by
adding `amd_pstate=disable` to kernel command line.

Acked-by: Huang Rui <ray.huang at amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy at amd.com>
Tested-by: Wyes Karny <wyes.karny at amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan at amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
(cherry picked from commit 1056d314709d0607a22e589c54b1e47e0da57b9d)
Signed-off-by: Paolo Pisati <paolo.pisati at canonical.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b4beafa59fe1..877ec0657e24 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6586,3 +6586,14 @@
 				memory, and other data can't be written using
 				xmon commands.
 			off	xmon is disabled.
+
+	amd_pstate=	[X86]
+			disable
+			  Do not enable amd_pstate as the default
+			  scaling driver for the supported processors
+			passive
+			  Use amd_pstate as a scaling driver, driver requests a
+			  desired performance on this abstract scale and the power
+			  management firmware translates the requests into actual
+			  hardware states (core frequency, data fabric and memory
+			  clocks etc.)
-- 
2.34.1