drm/amd/display: Add power down display on boot flag

[Why]

Due to the generic introduction of seamless boot, the display is no
longer blanked upon boot. However, this causes corruption on some
systems that does not lock the memory in the non-secure boot case,
resulting in brief corruption on boot due to garbage being written into
the frame buffer.

[How]
Add a flag, read during DC init, to determine whether display should be
blanked on boot. Default to true.
Signed-off-by: Thomas Lim <Thomas.Lim@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -534,6 +534,8 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 	if (amdgpu_dc_feature_mask & DC_FBC_MASK)
 		init_data.flags.fbc_support = true;
 
+	init_data.flags.power_down_display_on_boot = true;
+
 	/* Display Core create. */
 	adev->dm.dc = dc_create(&init_data);
 

drivers/gpu/drm/amd/display/dc/dc.h

@@ -204,6 +204,7 @@ struct dc_config {
 	bool optimize_edp_link_rate;
 	bool disable_fractional_pwm;
 	bool allow_seamless_boot_optimization;
+	bool power_down_display_on_boot;
 };
 
 enum visual_confirm {

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c

@@ -1118,7 +1118,7 @@ static void dcn10_init_hw(struct dc *dc)
 	 * Otherwise, if taking control is not possible, we need to power
 	 * everything down.
 	 */
-	if (dcb->funcs->is_accelerated_mode(dcb)) {
+	if (dcb->funcs->is_accelerated_mode(dcb) || dc->config.power_down_display_on_boot) {
 		for (i = 0; i < dc->res_pool->pipe_count; i++) {
 			struct hubp *hubp = dc->res_pool->hubps[i];
 			struct dpp *dpp = dc->res_pool->dpps[i];