From 738c27085668391e3f99adbe6777a58b2ba89f06 Mon Sep 17 00:00:00 2001
From: Alvin Lee <Alvin.Lee2@amd.com>
Date: Mon, 17 Aug 2026 13:52:44 -0400
Subject: [PATCH] drm/amd/display: Disable alt-ch until dependencies are ready

[Description]
- Alt-Ch cannot be enabled until all dependncies are ready (SMU needs
  to support double p-state + IFWI needs to support G7 regions
  enabled).
- If PMFW enables UCLK DPM without double p-state support and alt-ch
  is enabled then hangs could occur

Reviewed-by: Dillon Varone <Dillon.Varone@amd.com>
Signed-off-by: Alvin Lee <Alvin.Lee2@amd.com>
Signed-off-by: Ivan Lipsi <ivan.lipski@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/amd/display/dc/resource/dcn60/dcn60_resource.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn60/dcn60_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn60/dcn60_resource.c
index 7171b237c427..d7947105af22 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn60/dcn60_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn60/dcn60_resource.c
@@ -671,6 +671,8 @@ static const struct dc_debug_options debug_defaults_drv = {
 		}
 	},
 	.force_cositing = CHROMA_COSITING_NONE + 1,
+	.dml21_disable_pstate_method_mask = 0x20, // disable alt-ch unconditionally until dependencies are ready
+
 };
 
 static const struct dc_check_config config_defaults = {