From a2acb6fcd7fd125f43fe349b9d949150e275767e Mon Sep 17 00:00:00 2001
From: Qubot <1445788683@qq.com>
Date: Fri, 5 Jun 2026 21:14:10 +0800
Subject: [PATCH] drm/sunxi-hdmi: keep forced connector connected

---
 bsp/drivers/drm/sunxi_drm_hdmi.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/bsp/drivers/drm/sunxi_drm_hdmi.c b/bsp/drivers/drm/sunxi_drm_hdmi.c
index cb2e1e0a8..6036783f2 100644
--- a/bsp/drivers/drm/sunxi_drm_hdmi.c
+++ b/bsp/drivers/drm/sunxi_drm_hdmi.c
@@ -1479,6 +1479,21 @@ static int _sunxi_drv_hdmi_thread(void *parg)
 		} else if (ret == 0x2)
 			goto next_loop;
 
+		/*
+		 * The kernel command line may force the connector on
+		 * (video=HDMI-A-1:e).  In that mode a transient HPD low after a
+		 * modeset/DPMS transition must not be treated as a real unplug,
+		 * otherwise the driver tears down HDMI and immediately modesets it
+		 * again, which shows up as a periodic HDMI "jump" on screen.
+		 */
+		if (hdmi->hdmi_ctrl.drm_hpd_force == DRM_FORCE_ON) {
+			if (!_sunxi_drv_hdmi_hpd_get(hdmi)) {
+				temp_hpd = 1;
+				goto handle_change;
+			}
+			goto next_loop;
+		}
+
 		/* check physical hpd state */
 		temp_hpd = sunxi_hdmi_get_hpd();
 		if (temp_hpd == _sunxi_drv_hdmi_hpd_get(hdmi))
@@ -2664,7 +2679,8 @@ static int _sunxi_drm_hdmi_get_modes(struct drm_connector *connector)
 		return -1;
 	}
 
-	if (!_sunxi_drv_hdmi_hpd_get(hdmi))
+	if (!_sunxi_drv_hdmi_hpd_get(hdmi) &&
+			hdmi->hdmi_ctrl.drm_hpd_force != DRM_FORCE_ON)
 		return -1;
 
 	ret = _sunxi_drv_hdmi_read_edid(hdmi);
@@ -2772,7 +2788,10 @@ _sunxi_drm_hdmi_detect(struct drm_connector *connector, bool force)
 		return ret;
 	}
 
-	ret = _sunxi_drv_hdmi_hpd_get(hdmi);
+	if (hdmi->hdmi_ctrl.drm_hpd_force == DRM_FORCE_ON)
+		ret = 1;
+	else
+		ret = _sunxi_drv_hdmi_hpd_get(hdmi);
 	hdmi_inf("drm hdmi detect: %s\n", ret ? "connect" : "disconnect");
 	return ret == 1 ? connector_status_connected : connector_status_disconnected;
 }
@@ -2789,10 +2808,13 @@ static void _sunxi_drm_hdmi_force(struct drm_connector *connector)
 
 	hdmi->hdmi_ctrl.drm_hpd_force = (int)connector->force;
 
-	if (connector->force == DRM_FORCE_ON)
+	if (connector->force == DRM_FORCE_ON) {
 		_sunxi_drv_hdmi_hpd_plugin(hdmi);
-	else if (connector->force == DRM_FORCE_OFF)
+		_sunxi_drv_hdmi_hpd_set(hdmi, 0x1);
+	} else if (connector->force == DRM_FORCE_OFF) {
 		_sunxi_drv_hdmi_hpd_plugout(hdmi);
+		_sunxi_drv_hdmi_hpd_set(hdmi, 0x0);
+	}
 
 	hdmi_inf("drm hdmi set force hpd: %s\n", force_string[connector->force]);
 }