From ed3803533c7bf7df88bc3fc9f70bd317e1228ea8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timur=20Krist=C3=B3f?= <timur.kristof@gmail.com>
Date: Thu, 28 Aug 2025 17:11:09 +0200
Subject: [PATCH 4949/5403] drm/amd/pm: Disable MCLK switching with non-DC at
 120 Hz+ (v2)
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According to pp_pm_compute_clocks the non-DC display code
has "issues with mclk switching with refresh rates over 120 hz".
The workaround is to disable MCLK switching in this case.

Do the same for legacy DPM.

Fixes: 6ddbd37f1074 ("drm/amd/pm: optimize the amdgpu_pm_compute_clocks() implementations")
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/amd/pm/amdgpu_dpm_internal.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/amd/pm/amdgpu_dpm_internal.c b/drivers/gpu/drm/amd/pm/amdgpu_dpm_internal.c
index 42efe838fa85..2d2d2d5e6763 100644
--- a/drivers/gpu/drm/amd/pm/amdgpu_dpm_internal.c
+++ b/drivers/gpu/drm/amd/pm/amdgpu_dpm_internal.c
@@ -66,6 +66,13 @@ u32 amdgpu_dpm_get_vblank_time(struct amdgpu_device *adev)
 					(amdgpu_crtc->v_border * 2));
 
 				vblank_time_us = vblank_in_pixels * 1000 / amdgpu_crtc->hw_mode.clock;
+
+				/* we have issues with mclk switching with
+				 * refresh rates over 120 hz on the non-DC code.
+				 */
+				if (drm_mode_vrefresh(&amdgpu_crtc->hw_mode) > 120)
+					vblank_time_us = 0;
+
 				break;
 			}
 		}
-- 
2.54.0

