From: Harry Wentland <harry.wentland@amd.com>
Date: Thu, 12 Apr 2018 16:37:09 -0400
Subject: drm/amd/display: Don't program bypass on linear regamma LUT
Git-commit: d78fd7255881645fc645e23145d469385227170d
Patch-mainline: v4.17-rc2
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Even though this is required for degamma since DCE HW only supports a
couple predefined LUTs we can just program the LUT directly for regamma.

This fixes dark screens which occurs when we program regamma to bypass
while degamma is using srgb LUT.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Leo Li <sunpeng.li@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c |    7 -------
 1 file changed, 7 deletions(-)

--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
@@ -138,13 +138,6 @@ int amdgpu_dm_set_regamma_lut(struct dm_
 	lut = (struct drm_color_lut *)blob->data;
 	lut_size = blob->length / sizeof(struct drm_color_lut);
 
-	if (__is_lut_linear(lut, lut_size)) {
-		/* Set to bypass if lut is set to linear */
-		stream->out_transfer_func->type = TF_TYPE_BYPASS;
-		stream->out_transfer_func->tf = TRANSFER_FUNCTION_LINEAR;
-		return 0;
-	}
-
 	gamma = dc_create_gamma();
 	if (!gamma)
 		return -ENOMEM;