drm: panel-backlight-quirks: Log applied panel brightness quirks

Currently, when a panel brightness quirk is applied, there is no log
indicating that a quirk was applied. Unwrap the drm device on its own
and use drm_info() to log when a quirk is applied.

Suggested-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
Link: https://lore.kernel.org/r/20250829145541.512671-7-lkml@antheas.dev
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
(Correct a missing -1 in the message math)
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>

Author: antheas

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

@@ -3617,13 +3617,15 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
 	struct drm_connector *conn_base;
 	struct amdgpu_device *adev;
 	struct drm_luminance_range_info *luminance_range;
+	struct drm_device *drm;
 
 	if (aconnector->bl_idx == -1 ||
 	    aconnector->dc_link->connector_signal != SIGNAL_TYPE_EDP)
 		return;
 
 	conn_base = &aconnector->base;
-	adev = drm_to_adev(conn_base->dev);
+	drm = conn_base->dev;
+	adev = drm_to_adev(drm);
 
 	caps = &adev->dm.backlight_caps[aconnector->bl_idx];
 	caps->ext_caps = &aconnector->dc_link->dpcd_sink_ext_caps;
@@ -3659,12 +3661,20 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
 	panel_backlight_quirk =
 		drm_get_panel_backlight_quirk(aconnector->drm_edid);
 	if (!IS_ERR_OR_NULL(panel_backlight_quirk)) {
-		if (panel_backlight_quirk->min_brightness)
+		if (panel_backlight_quirk->min_brightness) {
 			caps->min_input_signal =
 				panel_backlight_quirk->min_brightness - 1;
-		if (panel_backlight_quirk->brightness_mask)
+			drm_info(drm,
+				 "Applying panel backlight quirk, min_brightness: %d\n",
+				 caps->min_input_signal);
+		}
+		if (panel_backlight_quirk->brightness_mask) {
+			drm_info(drm,
+				 "Applying panel backlight quirk, brightness_mask: 0x%X\n",
+				 panel_backlight_quirk->brightness_mask);
 			caps->brightness_mask =
 				panel_backlight_quirk->brightness_mask;
+		}
 	}
 }