FAILED: patch "[PATCH] drm/amd/powerplay/vega10: allow mclk switching with no" failed to apply to 4.16-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.16-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From d6bca7e7146796002308988e913d493f0c67bec0 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Tue, 13 Feb 2018 14:25:11 -0500
Subject: [PATCH] drm/amd/powerplay/vega10: allow mclk switching with no
 displays

If there are no displays attached, there is no reason to disable
mclk switching.

Fixes mclks getting set to high when there are no displays attached.

Reviewed-by: Eric Huang <JinhuiEric.Huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
index 6a153ad1b942..1d442a498bf6 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
@@ -3171,10 +3171,13 @@ static int vega10_apply_state_adjust_rules(struct pp_hwmgr *hwmgr,
 		PP_CAP(PHM_PlatformCaps_DisableMclkSwitchForVR);
 	force_mclk_high = PP_CAP(PHM_PlatformCaps_ForceMclkHigh);
 
-	disable_mclk_switching = (info.display_count > 1) ||
-				    disable_mclk_switching_for_frame_lock ||
-				    disable_mclk_switching_for_vr ||
-				    force_mclk_high;
+	if (info.display_count == 0)
+		disable_mclk_switching = false;
+	else
+		disable_mclk_switching = (info.display_count > 1) ||
+			disable_mclk_switching_for_frame_lock ||
+			disable_mclk_switching_for_vr ||
+			force_mclk_high;
 
 	sclk = vega10_ps->performance_levels[0].gfx_clock;
 	mclk = vega10_ps->performance_levels[0].mem_clock;