drm/vc4: Fall back to using an EDID probe in the absence of a GPIO.

On Pi0/1/2, we use an external GPIO line for hotplug detection, since the HDMI_HOTPLUG register isn't connected to anything. However, with the Pi3 the HPD GPIO line has moved off to a GPIO expander that will be tricky to get to (the firmware is constantly polling the expander using i2c0, so we'll need to coordinate with it). As a stop-gap, if we don't have a GPIO line, use an EDID probe to detect connection. Fixes HDMI display on the pi3. Signed-off-by: Eric Anholt <[email protected]>
anholt · Oct 6, 2016 · 9d44abb · 9d44abb
1 parent 6e1cbba
commit 9d44abb
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -174,6 +174,9 @@ vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
 			return connector_status_disconnected;
 	}
 
+	if (drm_probe_ddc(vc4->hdmi->ddc))
+		return connector_status_connected;
+
 	if (HDMI_READ(VC4_HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED)
 		return connector_status_connected;
 	else