Merge tag 'pm-6.1-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These revert a recent change in the schedutil cpufreq governor that
  had not been expected to make any functional difference, but turned
  out to introduce a performance regression, fix an initialization issue
  in the amd-pstate driver and make it actually replace the venerable
  ACPI cpufreq driver on the supported systems by default.

  Specifics:

   - Revert a recent schedutil cpufreq governor change that introduced a
     performace regression on Pixel 6 (Sam Wu)

   - Fix amd-pstate driver initialization after running the kernel via
     kexec (Wyes Karny)

   - Turn amd-pstate into a built-in driver which allows it to take
     precedence over acpi-cpufreq by default on supported systems and
     amend it with a mechanism to disable this behavior (Perry Yuan)

   - Update amd-pstate documentation in accordance with the other
     changes made to it (Perry Yuan)"

* tag 'pm-6.1-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Documentation: add amd-pstate kernel command line options
  Documentation: amd-pstate: add driver working mode introduction
  cpufreq: amd-pstate: add amd-pstate driver parameter for mode selection
  cpufreq: amd-pstate: change amd-pstate driver to be built-in type
  cpufreq: amd-pstate: cpufreq: amd-pstate: reset MSR_AMD_PERF_CTL register at init
  Revert "cpufreq: schedutil: Move max CPU capacity to sugov_policy"

2 files changed, 24 insertions, 17 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a465d5242774..42af9ca0127e 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6959,3 +6959,14 @@
 				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.)
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 8f3d30c5a0d8..06e23538f79c 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -283,23 +283,19 @@ efficiency frequency management method on AMD processors.
 Kernel Module Options for ``amd-pstate``
 =========================================
 
-.. _shared_mem:
-
-``shared_mem``
-Use a module param (shared_mem) to enable related processors manually with
-**amd_pstate.shared_mem=1**.
-Due to the performance issue on the processors with `Shared Memory Support
-<perf_cap_>`_, we disable it presently and will re-enable this by default
-once we address performance issue with this solution.
-
-To check whether the current processor is using `Full MSR Support <perf_cap_>`_
-or `Shared Memory Support <perf_cap_>`_ : ::
-
-  ray@hr-test1:~$ lscpu | grep cppc
-  Flags:                           fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local clzero irperf xsaveerptr rdpru wbnoinvd cppc arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip pku ospke vaes vpclmulqdq rdpid overflow_recov succor smca fsrm
-
-If the CPU flags have ``cppc``, then this processor supports `Full MSR Support
-<perf_cap_>`_. Otherwise, it supports `Shared Memory Support <perf_cap_>`_.
+Passive Mode
+------------
+
+``amd_pstate=passive``
+
+It will be enabled if the ``amd_pstate=passive`` is passed to the kernel in the command line.
+In this mode, ``amd_pstate`` driver software specifies a desired QoS target in the CPPC
+performance scale as a relative number. This can be expressed as percentage of nominal
+performance (infrastructure max). Below the nominal sustained performance level,
+desired performance expresses the average performance level of the processor subject
+to the Performance Reduction Tolerance register. Above the nominal performance level,
+processor must provide at least nominal performance requested and go higher if current
+operating conditions allow.
 
 
 ``cpupower`` tool support for ``amd-pstate``