drm/fbdev: rework output polling to be back in the core. (v4)

After thinking it over a lot it made more sense for the core to deal with
the output polling especially so it can notify X.

v2: drop plans for fake connector - per Michel's comments - fix X patch sent to xorg-devel, add intel polled/hpd setting, add initial nouveau polled/hpd settings.

v3: add config lock take inside polling, add intel/nouveau poll init/fini calls

v4: config lock was a bit agressive, only needed around connector list reading.
otherwise it could re-enter.

glisse: discard drm_helper_hpd_irq_event

v3: Reviewed-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index c489346..765854e 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -1085,6 +1085,7 @@
 		drm_connector_attach_property(&radeon_connector->base,
 					      rdev->mode_info.load_detect_property,
 					      1);
+		connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 		break;
 	case DRM_MODE_CONNECTOR_DVIA:
 		drm_connector_init(dev, &radeon_connector->base, &radeon_vga_connector_funcs, connector_type);
@@ -1211,6 +1212,12 @@
 		break;
 	}
 
+	if (hpd->hpd == RADEON_HPD_NONE) {
+		if (i2c_bus->valid)
+			connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	} else
+		connector->polled = DRM_CONNECTOR_POLL_HPD;
+
 	connector->display_info.subpixel_order = subpixel_order;
 	drm_sysfs_connector_add(connector);
 	return;
@@ -1272,6 +1279,7 @@
 		drm_connector_attach_property(&radeon_connector->base,
 					      rdev->mode_info.load_detect_property,
 					      1);
+		connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 		break;
 	case DRM_MODE_CONNECTOR_DVIA:
 		drm_connector_init(dev, &radeon_connector->base, &radeon_vga_connector_funcs, connector_type);
@@ -1338,6 +1346,11 @@
 		break;
 	}
 
+	if (hpd->hpd == RADEON_HPD_NONE) {
+		if (i2c_bus->valid)
+			connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	} else
+		connector->polled = DRM_CONNECTOR_POLL_HPD;
 	connector->display_info.subpixel_order = subpixel_order;
 	drm_sysfs_connector_add(connector);
 	return;