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[6/6] Documentation: add amd-pstate kernel command line options

Message ID 20221128163848.362359-7-paolo.pisati@canonical.com
State New
Headers show
Series Fix AMD-PState driver for Genoa CPU | expand

Commit Message

Paolo Pisati Nov. 28, 2022, 4:38 p.m. UTC 
From: Perry Yuan <Perry.Yuan@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@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 1056d314709d0607a22e589c54b1e47e0da57b9d)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)
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Patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 18417e6e26d2..364f1d6f4be4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6878,3 +6878,14 @@ 
 				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.)