[PATCH 06/32] drm/amd/display: workaround for oled eDP not lighting up on DCN401

[Zaeem Mohamed]

From: Joshua Aberback <joshua.aberback at amd.com>

[Why]
Currently there's an issue on DCN401 that prevents oled eDP panels from
being lit up that is still under investigation. To unblock dev work
while investigating, we can work around the issue by skipping toggling
the enablement of the backlight.

[How]
 - new debug bit that will skip touching backlight enable DPCD for oled

Reviewed-by: Alvin Lee <alvin.lee2 at amd.com>
Reviewed-by: Wenjing Liu <wenjing.liu at amd.com>
Acked-by: Zaeem Mohamed <zaeem.mohamed at amd.com>
Signed-off-by: Joshua Aberback <joshua.aberback at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc.h                            | 1 +
 .../drm/amd/display/dc/link/protocols/link_edp_panel_control.c | 3 +++
 .../gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c   | 1 +
 3 files changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index d0ed01ac460d..a06015165a61 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -1042,6 +1042,7 @@ struct dc_debug_options {
 	unsigned int force_easf;
 	unsigned int force_sharpness;
 	unsigned int force_lls;
+	bool edp_oled_no_backlight_enable;
 };
 
 
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
index ad9aca790dd7..89f66d88c3b0 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
@@ -248,6 +248,9 @@ bool edp_backlight_enable_aux(struct dc_link *link, bool enable)
 		link->connector_signal != SIGNAL_TYPE_DISPLAY_PORT))
 		return false;
 
+	if (link->dc->debug.edp_oled_no_backlight_enable && link->dpcd_sink_ext_caps.bits.oled)
+		return true;
+
 	if (core_link_write_dpcd(link, DP_SOURCE_BACKLIGHT_ENABLE,
 		&backlight_enable, 1) != DC_OK)
 		return false;
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c
index 247bac177d1b..92206b69b2f7 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c
@@ -732,6 +732,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	},
 	.force_cositing = CHROMA_COSITING_TOPLEFT + 1,
 	.disable_idle_power_optimizations = true,
+	.edp_oled_no_backlight_enable = true,
 };
 
 static struct dce_aux *dcn401_aux_engine_create(
-- 
2.34.1