From: Timur Kristóf <timur.kristof@gmail.com>
Date: Tue, 28 Apr 2026 11:40:40 +0000 (+0200)
Subject: drm/amd/display: Allow embedded connectors without DDC
X-Git-Tag: v7.1-rc2~7^2~1^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=494941aa772dab79251543764db6cd14bd337e43;p=thirdparty%2Fkernel%2Flinux.git

drm/amd/display: Allow embedded connectors without DDC

On some laptops, the embedded panel may not have
a DDC (display data channel) available. On these,
the EDID may be hardcoded in ACPI or the VBIOS.

In this case, use GPIO_DDC_LINE_UNKNOWN and don't fail.

Fixes: def3488eb0fd ("drm/amd/display: refactor HPD to increase flexibility")
Link: https://gitlab.freedesktop.org/drm/amd/-/work_items/5192
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 75b8a6ca0e8bc3ce24572f854e95f8721b321179)
---

diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index 7f55ba09b191..37714d4371fb 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -1682,7 +1682,7 @@ struct dc_scratch_space {
 	struct dc_link_training_overrides preferred_training_settings;
 	struct dp_audio_test_data audio_test_data;
 
-	uint8_t ddc_hw_inst;
+	enum gpio_ddc_line ddc_hw_inst;
 
 	uint8_t hpd_src;
 
diff --git a/drivers/gpu/drm/amd/display/dc/gpio/gpio_service.c b/drivers/gpu/drm/amd/display/dc/gpio/gpio_service.c
index a2c46350e44e..95f8b7c7d657 100644
--- a/drivers/gpu/drm/amd/display/dc/gpio/gpio_service.c
+++ b/drivers/gpu/drm/amd/display/dc/gpio/gpio_service.c
@@ -646,6 +646,9 @@ failure:
 enum gpio_ddc_line dal_ddc_get_line(
 	const struct ddc *ddc)
 {
+	if (!ddc)
+		return GPIO_DDC_LINE_UNKNOWN;
+
 	return (enum gpio_ddc_line)dal_gpio_get_enum(ddc->pin_data);
 }
 
diff --git a/drivers/gpu/drm/amd/display/dc/link/link_factory.c b/drivers/gpu/drm/amd/display/dc/link/link_factory.c
index 7e7682d7dfc8..ae4c4ad05baa 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_factory.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_factory.c
@@ -568,7 +568,9 @@ static bool construct_phy(struct dc_link *link,
 		goto ddc_create_fail;
 	}
 
-	if (!link->ddc->ddc_pin) {
+	/* Embedded display connectors such as LVDS may not have DDC. */
+	if (!link->ddc->ddc_pin &&
+	    !dc_is_embedded_signal(link->connector_signal)) {
 		DC_ERROR("Failed to get I2C info for connector!\n");
 		goto ddc_create_fail;
 	}