cpufreq: amd-pstate: Add explanation for X86_AMD_PSTATE_UT

This kernel module is used for testing. It's safe to say M here.
It can also be built-in without X86_AMD_PSTATE enabled.
Currently, only tests for amd-pstate are supported. If X86_AMD_PSTATE
is set disabled, it can tell the users test can only run on amd-pstate
driver, please set X86_AMD_PSTATE enabled.
In the future, comparison tests will be added. It can set amd-pstate
disabled and set acpi-cpufreq enabled to run test cases, then compare
the test results.

Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Meng Li <li.meng@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

drivers/cpufreq/Kconfig.x86

@@ -58,6 +58,14 @@ config X86_AMD_PSTATE_UT
 	help
 	  This kernel module is used for testing. It's safe to say M here.
 
+	  It can also be built-in without X86_AMD_PSTATE enabled.
+	  Currently, only tests for amd-pstate are supported. If X86_AMD_PSTATE
+	  is set disabled, it can tell the users test can only run on amd-pstate
+	  driver, please set X86_AMD_PSTATE enabled.
+	  In the future, comparison tests will be added. It can set amd-pstate
+	  disabled and set acpi-cpufreq enabled to run test cases, then compare
+	  the test results.
+
 config X86_ACPI_CPUFREQ
 	tristate "ACPI Processor P-States driver"
 	depends on ACPI_PROCESSOR

tools/testing/selftests/amd-pstate/amd-pstate-ut.sh

@@ -32,6 +32,7 @@ fi
 scaling_driver=$(cat /sys/devices/system/cpu/cpufreq/policy0/scaling_driver)
 if [ "$scaling_driver" != "amd-pstate" ]; then
 	echo "$0 # Skipped: Test can only run on amd-pstate driver."
+	echo "$0 # Please set X86_AMD_PSTATE enabled."
 	echo "$0 # Current cpufreq scaling drvier is $scaling_driver."
 	exit $ksft_skip
 fi