[PATCH 1/3] drm/ast: Handle failed I2C initialization gracefully

[Thomas Zimmermann <tzimmermann@suse.de>]

I2C initialization is allowed to fail. In this case, create a connector
without DDC adapter. The current code would dereference a NULL pointer.

Reading the modes from the connector is supposed to work without I2C
adapter. Add the respective test.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/ast/ast_mode.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 1e30eaeb0e1b..3f0c8c1f9777 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1226,7 +1226,7 @@ static int ast_get_modes(struct drm_connector *connector)
 		else
 			kfree(edid);
 	}
-	if (!flags)
+	if (!flags && ast_connector->i2c)
 		edid = drm_get_edid(connector, &ast_connector->i2c->adapter);
 	if (edid) {
 		drm_connector_update_edid_property(&ast_connector->base, edid);
@@ -1332,10 +1332,13 @@ static int ast_connector_init(struct drm_device *dev)
 	if (!ast_connector->i2c)
 		drm_err(dev, "failed to add ddc bus for connector\n");
 
-	drm_connector_init_with_ddc(dev, connector,
-				    &ast_connector_funcs,
-				    DRM_MODE_CONNECTOR_VGA,
-				    &ast_connector->i2c->adapter);
+	if (ast_connector->i2c)
+		drm_connector_init_with_ddc(dev, connector, &ast_connector_funcs,
+					    DRM_MODE_CONNECTOR_VGA,
+					    &ast_connector->i2c->adapter);
+	else
+		drm_connector_init(dev, connector, &ast_connector_funcs,
+				   DRM_MODE_CONNECTOR_VGA);
 
 	drm_connector_helper_add(connector, &ast_connector_helper_funcs);
 
-- 
2.34.0