Patch "cpufreq/amd-pstate: Fix amd_pstate mode switch on shared memory systems" has been added to the 6.11-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: Fix amd_pstate mode switch on shared memory systems

to the 6.11-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-fix-amd_pstate-mode-switch-on-sha.patch
and it can be found in the queue-6.11 subdirectory.

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



commit 70b4bf77e09ee31d6cb7e03bab4e9447c6030b72
Author: Dhananjay Ugwekar <Dhananjay.Ugwekar@xxxxxxx>
Date:   Fri Oct 4 12:23:04 2024 +0000

    cpufreq/amd-pstate: Fix amd_pstate mode switch on shared memory systems
    
    [ Upstream commit c10e50a469b5ec91eabf653526a22bdce03a9bca ]
    
    While switching the driver mode between active and passive, Collaborative
    Processor Performance Control (CPPC) is disabled in
    amd_pstate_unregister_driver(). But, it is not enabled back while registering
    the new driver (passive or active). This leads to the new driver mode not
    working correctly, so enable it back in amd_pstate_register_driver().
    
    Fixes: 3ca7bc818d8c ("cpufreq: amd-pstate: Add guided mode control support via sysfs")
    Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@xxxxxxx>
    Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
    Link: https://lore.kernel.org/r/20241004122303.94283-1-Dhananjay.Ugwekar@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 589fde37ccd7a..929b9097a6c17 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1281,11 +1281,21 @@ static int amd_pstate_register_driver(int mode)
 		return -EINVAL;
 
 	cppc_state = mode;
+
+	ret = amd_pstate_enable(true);
+	if (ret) {
+		pr_err("failed to enable cppc during amd-pstate driver registration, return %d\n",
+		       ret);
+		amd_pstate_driver_cleanup();
+		return ret;
+	}
+
 	ret = cpufreq_register_driver(current_pstate_driver);
 	if (ret) {
 		amd_pstate_driver_cleanup();
 		return ret;
 	}
+
 	return 0;
 }