staging: vboxvideo: Fix reporting invalid suggested-offset-properties

The x and y hints receives from the host are unsigned 32 bit integers and
they get set to -1 (0xffffffff) when invalid. Before this commit the
vboxvideo driver was storing them in an u16 causing the -1 to be truncated
to 65535 which, once reported to userspace, was breaking gnome 3.26+
in Wayland mode.

This commit stores the host values in 32 bit variables, removing the
truncation and checks for -1, replacing it with 0 as -1 is not a valid
suggested-offset-property value. Likewise the properties are now
initialized to 0 instead of -1, since -1 is not a valid value.
This fixes gnome 3.26+ in Wayland mode not working with the vboxvideo
driver.

Reported-by: Gianfranco Costamagna <locutusofborg@debian.org>
Cc: stable@vger.kernel.org
Cc: Michael Thayer <michael.thayer@oracle.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vboxvideo/vbox_drv.h

@@ -137,8 +137,8 @@ struct vbox_connector {
 	char name[32];
 	struct vbox_crtc *vbox_crtc;
 	struct {
-		u16 width;
-		u16 height;
+		u32 width;
+		u32 height;
 		bool disconnected;
 	} mode_hint;
 };
@@ -150,8 +150,8 @@ struct vbox_crtc {
 	unsigned int crtc_id;
 	u32 fb_offset;
 	bool cursor_enabled;
-	u16 x_hint;
-	u16 y_hint;
+	u32 x_hint;
+	u32 y_hint;
 };
 
 struct vbox_encoder {

drivers/staging/vboxvideo/vbox_irq.c

@@ -150,8 +150,8 @@ static void vbox_update_mode_hints(struct vbox_private *vbox)
 
 		disconnected = !(hints->enabled);
 		crtc_id = vbox_conn->vbox_crtc->crtc_id;
-		vbox_conn->mode_hint.width = hints->cx & 0x8fff;
-		vbox_conn->mode_hint.height = hints->cy & 0x8fff;
+		vbox_conn->mode_hint.width = hints->cx;
+		vbox_conn->mode_hint.height = hints->cy;
 		vbox_conn->vbox_crtc->x_hint = hints->dx;
 		vbox_conn->vbox_crtc->y_hint = hints->dy;
 		vbox_conn->mode_hint.disconnected = disconnected;

drivers/staging/vboxvideo/vbox_mode.c

@@ -553,12 +553,22 @@ static int vbox_get_modes(struct drm_connector *connector)
 		++num_modes;
 	}
 	vbox_set_edid(connector, preferred_width, preferred_height);
-	drm_object_property_set_value(
-		&connector->base, vbox->dev->mode_config.suggested_x_property,
-		vbox_connector->vbox_crtc->x_hint);
-	drm_object_property_set_value(
-		&connector->base, vbox->dev->mode_config.suggested_y_property,
-		vbox_connector->vbox_crtc->y_hint);
+
+	if (vbox_connector->vbox_crtc->x_hint != -1)
+		drm_object_property_set_value(&connector->base,
+			vbox->dev->mode_config.suggested_x_property,
+			vbox_connector->vbox_crtc->x_hint);
+	else
+		drm_object_property_set_value(&connector->base,
+			vbox->dev->mode_config.suggested_x_property, 0);
+
+	if (vbox_connector->vbox_crtc->y_hint != -1)
+		drm_object_property_set_value(&connector->base,
+			vbox->dev->mode_config.suggested_y_property,
+			vbox_connector->vbox_crtc->y_hint);
+	else
+		drm_object_property_set_value(&connector->base,
+			vbox->dev->mode_config.suggested_y_property, 0);
 
 	return num_modes;
 }
@@ -640,9 +650,9 @@ static int vbox_connector_init(struct drm_device *dev,
 
 	drm_mode_create_suggested_offset_properties(dev);
 	drm_object_attach_property(&connector->base,
-				   dev->mode_config.suggested_x_property, -1);
+				   dev->mode_config.suggested_x_property, 0);
 	drm_object_attach_property(&connector->base,
-				   dev->mode_config.suggested_y_property, -1);
+				   dev->mode_config.suggested_y_property, 0);
 	drm_connector_register(connector);
 
 	drm_mode_connector_attach_encoder(connector, encoder);