drm: apple: HPD: Only act on connect IRQs

DCP notices the disconnects on its own and the parallel handling just
results in confusion (both on DRM and developer side).

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/dcp.c

@@ -314,12 +314,16 @@ static irqreturn_t dcp_dp2hdmi_hpd(int irq, void *data)
 	struct apple_dcp *dcp = data;
 	bool connected = gpiod_get_value_cansleep(dcp->hdmi_hpd);
 
-	dev_info(dcp->dev, "DP2HDMI HPD connected:%d\n", connected);
+	/* do nothing on disconnect and trust that dcp detects it itself.
+	 * Parallel disconnect HPDs result drm disabling the CRTC even when it
+	 * should not.
+	 * The interrupt should be changed to rising but for now the disconnect
+	 * IRQs might be helpful for debugging.
+	 */
+	dev_info(dcp->dev, "DP2HDMI HPD irq, connected:%d\n", connected);
 
 	if (connected)
 		dcp_dptx_connect(dcp, 0);
-	else
-		dcp_dptx_disconnect(dcp, 0);
 
 	return IRQ_HANDLED;
 }