From: Gabe Teeger <gabe.teeger@amd.com>
Date: Thu, 21 May 2026 15:06:22 +0000 (-0400)
Subject: drm/amd/display: Handle aux_inst for connectors without DDC pin
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d447370678c4c4d335fd0422341b76f8cf8f3b3;p=thirdparty%2Flinux.git

drm/amd/display: Handle aux_inst for connectors without DDC pin

[Why & How]
Must use an alternative codepath to access AUX channel when
link->no_ddc_pin is set.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Gabe Teeger <gabe.teeger@amd.com>
Signed-off-by: Matthew Stewart <Matthew.Stewart2@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---

diff --git a/drivers/gpu/drm/amd/display/modules/power/power.c b/drivers/gpu/drm/amd/display/modules/power/power.c
index 1dd65bdf8cc90..5659a38b33663 100644
--- a/drivers/gpu/drm/amd/display/modules/power/power.c
+++ b/drivers/gpu/drm/amd/display/modules/power/power.c
@@ -464,6 +464,7 @@ bool mod_power_notify_mode_change(struct mod_power *mod_power,
 	struct dc_link *link = NULL;
 	struct dc *dc = NULL;
 	unsigned int panel_inst = 0;
+	uint8_t aux_inst = 0;
 
 	if ((mod_power == NULL) || (stream == NULL))
 		return false;
@@ -482,8 +483,12 @@ bool mod_power_notify_mode_change(struct mod_power *mod_power,
 	link = dc_stream_get_link(stream);
 
 	if (link != NULL && dc_get_edp_link_panel_inst(dc, link, &panel_inst)) {
-		ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
-		uint8_t aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
+		if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
+			aux_inst = (uint8_t)link->aux_hw_inst;
+		} else {
+			ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
+			aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
+		}
 
 		mod_power_update_backlight_on_mode_change(core_power, link, panel_inst, aux_inst, is_hdr);
 
diff --git a/drivers/gpu/drm/amd/display/modules/power/power_abm.c b/drivers/gpu/drm/amd/display/modules/power/power_abm.c
index b94dbb9e64a73..a1a0563598b5c 100644
--- a/drivers/gpu/drm/amd/display/modules/power/power_abm.c
+++ b/drivers/gpu/drm/amd/display/modules/power/power_abm.c
@@ -849,8 +849,12 @@ bool mod_power_set_backlight_nits(struct mod_power *mod_power,
 	core_power = MOD_POWER_TO_CORE(mod_power);
 	link = dc_stream_get_link(stream);
 
-	ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
-	aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
+	if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
+		aux_inst = (uint8_t)link->aux_hw_inst;
+	} else {
+		ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
+		aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
+	}
 
 	if (!dc_get_edp_link_panel_inst(core_power->dc, stream->link, &panel_inst))
 		return false;
@@ -937,8 +941,12 @@ bool mod_power_set_backlight_percent(struct mod_power *mod_power,
 
 	core_power = MOD_POWER_TO_CORE(mod_power);
 	link = dc_stream_get_link(stream);
-	ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
-	aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
+	if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
+		aux_inst = (uint8_t)link->aux_hw_inst;
+	} else {
+		ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
+		aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
+	}
 
 	if (!dc_get_edp_link_panel_inst(core_power->dc, stream->link, &panel_inst))
 		return false;