From: Alex Deucher <alexander.deucher@amd.com>
Date: Tue, 13 Feb 2018 14:33:51 -0500
Subject: drm/amdgpu/cgs: add refresh rate checking to non-DC display code
Git-commit: 7a572b1eda235052b9e0a41954938fa29f4b0f20
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Clamp the vblank period to 0 if the refresh rate is larger than
120 hz for non-DC.  This allows us to remove the refresh rate
checks from powerplay for mclk switching.

Reviewed-by: Eric Huang <JinhuiEric.Huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
@@ -953,6 +953,11 @@ static int amdgpu_cgs_get_active_display
 								(amdgpu_crtc->v_border * 2);
 					mode_info->vblank_time_us = vblank_lines * line_time_us;
 					mode_info->refresh_rate = drm_mode_vrefresh(&amdgpu_crtc->hw_mode);
+					/* we have issues with mclk switching with refresh rates
+					 * over 120 hz on the non-DC code.
+					 */
+					if (mode_info->refresh_rate > 120)
+						mode_info->vblank_time_us = 0;
 					mode_info = NULL;
 				}
 			}