drm/vkms: Avoid assigning 0 for possible_crtc

When vkms invoke drm_universal_plane_init(), it sets 0 for
possible_crtcs parameter which means that planes can't be attached to
any CRTC. It currently works due to some safeguard in the drm_crtc file;
however, it is possible to identify the problem by trying to append a
second connector. This patch fixes this issue by modifying
vkms_plane_init() to accept an index parameter which makes the code a
little bit more flexible and avoid set zero to possible_crtcs.
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/d67849c62a8d8ace1a0af455998b588798a4c45f.1561491964.git.rodrigosiqueiramelo@gmail.com

drivers/gpu/drm/vkms/vkms_drv.c

@@ -127,7 +127,7 @@ static int vkms_modeset_init(struct vkms_device *vkmsdev)
 	dev->mode_config.preferred_depth = 24;
 	dev->mode_config.helper_private = &vkms_mode_config_helpers;
 
-	return vkms_output_init(vkmsdev);
+	return vkms_output_init(vkmsdev, 0);
 }
 
 static int __init vkms_init(void)

drivers/gpu/drm/vkms/vkms_drv.h

@@ -115,10 +115,10 @@ bool vkms_get_vblank_timestamp(struct drm_device *dev, unsigned int pipe,
 			       int *max_error, ktime_t *vblank_time,
 			       bool in_vblank_irq);
 
-int vkms_output_init(struct vkms_device *vkmsdev);
+int vkms_output_init(struct vkms_device *vkmsdev, int index);
 
 struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
-				  enum drm_plane_type type);
+				  enum drm_plane_type type, int index);
 
 /* Gem stuff */
 struct drm_gem_object *vkms_gem_create(struct drm_device *dev,

drivers/gpu/drm/vkms/vkms_output.c

@@ -35,7 +35,7 @@ static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {
 	.get_modes    = vkms_conn_get_modes,
 };
 
-int vkms_output_init(struct vkms_device *vkmsdev)
+int vkms_output_init(struct vkms_device *vkmsdev, int index)
 {
 	struct vkms_output *output = &vkmsdev->output;
 	struct drm_device *dev = &vkmsdev->drm;
@@ -45,12 +45,12 @@ int vkms_output_init(struct vkms_device *vkmsdev)
 	struct drm_plane *primary, *cursor = NULL;
 	int ret;
 
-	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
+	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY, index);
 	if (IS_ERR(primary))
 		return PTR_ERR(primary);
 
 	if (enable_cursor) {
-		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
+		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR, index);
 		if (IS_ERR(cursor)) {
 			ret = PTR_ERR(cursor);
 			goto err_cursor;

drivers/gpu/drm/vkms/vkms_plane.c

@@ -176,7 +176,7 @@ static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
 };
 
 struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
-				  enum drm_plane_type type)
+				  enum drm_plane_type type, int index)
 {
 	struct drm_device *dev = &vkmsdev->drm;
 	const struct drm_plane_helper_funcs *funcs;
@@ -198,7 +198,7 @@ struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 		funcs = &vkms_primary_helper_funcs;
 	}
 
-	ret = drm_universal_plane_init(dev, plane, 0,
+	ret = drm_universal_plane_init(dev, plane, 1 << index,
 				       &vkms_plane_funcs,
 				       formats, nformats,
 				       NULL, type, NULL);