Patch "cpufreq: amd-pstate: auto-load pstate driver by default" has been added to the 6.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    cpufreq: amd-pstate: auto-load pstate driver by default

to the 6.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cpufreq-amd-pstate-auto-load-pstate-driver-by-defaul.patch
and it can be found in the queue-6.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6b48e8f74e1ba147eb68634476b85012f1386776
Author: Perry Yuan <perry.yuan@xxxxxxx>
Date:   Wed Jun 19 23:40:19 2024 +0800

    cpufreq: amd-pstate: auto-load pstate driver by default
    
    [ Upstream commit 4e4f600ee750facedf6a5dc97e8ae0b627ab4573 ]
    
    If the `amd-pstate` driver is not loaded automatically by default,
    it is because the kernel command line parameter has not been added.
    To resolve this issue, it is necessary to call the `amd_pstate_set_driver()`
    function to enable the desired mode (passive/active/guided) before registering
    the driver instance.
    
    This ensures that the driver is loaded correctly without relying on the kernel
    command line parameter.
    
    When there is no parameter added to command line, Kernel config will
    provide the default mode to load.
    
    Meanwhile, user can add driver mode in command line which will override
    the kernel config default option.
    
    Reported-by: Andrei Amuraritei <andamu@xxxxxxxxxx>
    Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218705
    Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
    Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
    Link: https://lore.kernel.org/r/83301c4cea4f92fb19e14b23f2bac7facfd8bdbb.1718811234.git.perry.yuan@xxxxxxx
    Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 874ee90b1cf10..67c4a6a0ef124 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1764,8 +1764,13 @@ static int __init amd_pstate_init(void)
 	/* check if this machine need CPPC quirks */
 	dmi_check_system(amd_pstate_quirks_table);
 
-	switch (cppc_state) {
-	case AMD_PSTATE_UNDEFINED:
+	/*
+	* determine the driver mode from the command line or kernel config.
+	* If no command line input is provided, cppc_state will be AMD_PSTATE_UNDEFINED.
+	* command line options will override the kernel config settings.
+	*/
+
+	if (cppc_state == AMD_PSTATE_UNDEFINED) {
 		/* Disable on the following configs by default:
 		 * 1. Undefined platforms
 		 * 2. Server platforms
@@ -1777,15 +1782,20 @@ static int __init amd_pstate_init(void)
 			pr_info("driver load is disabled, boot with specific mode to enable this\n");
 			return -ENODEV;
 		}
-		ret = amd_pstate_set_driver(CONFIG_X86_AMD_PSTATE_DEFAULT_MODE);
-		if (ret)
-			return ret;
-		break;
+		/* get driver mode from kernel config option [1:4] */
+		cppc_state = CONFIG_X86_AMD_PSTATE_DEFAULT_MODE;
+	}
+
+	switch (cppc_state) {
 	case AMD_PSTATE_DISABLE:
+		pr_info("driver load is disabled, boot with specific mode to enable this\n");
 		return -ENODEV;
 	case AMD_PSTATE_PASSIVE:
 	case AMD_PSTATE_ACTIVE:
 	case AMD_PSTATE_GUIDED:
+		ret = amd_pstate_set_driver(cppc_state);
+		if (ret)
+			return ret;
 		break;
 	default:
 		return -EINVAL;
@@ -1806,7 +1816,7 @@ static int __init amd_pstate_init(void)
 	/* enable amd pstate feature */
 	ret = amd_pstate_enable(true);
 	if (ret) {
-		pr_err("failed to enable with return %d\n", ret);
+		pr_err("failed to enable driver mode(%d)\n", cppc_state);
 		return ret;
 	}