drm: introduce a capability flag for syncobj timeline support

Unfortunately userspace users of this API cannot be publicly disclosed
yet.

This commit effectively disables timeline syncobj ioctls for all
drivers. Each driver wishing to support this feature will need to
expose DRIVER_SYNCOBJ_TIMELINE.

v2: Add uAPI capability check (Christian)

Signed-off-by: Lionel Landwerlin <[e-mail]>
Reviewed-by: Christian König <[e-mail]> (v1)
Cc: Dave Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: Christian König <[e-mail]>
Cc: Chunming Zhou <[e-mail]>
Reviewed-by: Dave Airlie <[e-mail]>
Reviewed-by: Chunming Zhou <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_ioctl.c

···
 	case DRM_CAP_SYNCOBJ:
 		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ);
 		return 0;
+	case DRM_CAP_SYNCOBJ_TIMELINE:
+		req->value = drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE);
+		return 0;
 	}
 
 	/* Other caps only work with KMS drivers */

drivers/gpu/drm/drm_syncobj.c

···
 	struct drm_syncobj_transfer *args = data;
 	int ret;
 
-	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
 		return -EOPNOTSUPP;
 
 	if (args->pad)
···
 	struct drm_syncobj **syncobjs;
 	int ret = 0;
 
-	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
 		return -EOPNOTSUPP;
 
 	if (args->flags & ~(DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL |
···
 	uint32_t i, j;
 	int ret;
 
-	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
 		return -EOPNOTSUPP;
 
 	if (args->pad != 0)
···
 	uint32_t i;
 	int ret;
 
-	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
-		return -ENODEV;
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
+		return -EOPNOTSUPP;
 
 	if (args->pad != 0)
 		return -EINVAL;

include/drm/drm_drv.h

···
 	 * submission.
 	 */
 	DRIVER_SYNCOBJ                  = BIT(5),
+	/**
+	 * @DRIVER_SYNCOBJ_TIMELINE:
+	 *
+	 * Driver supports the timeline flavor of &drm_syncobj for explicit
+	 * synchronization of command submission.
+	 */
+	DRIVER_SYNCOBJ_TIMELINE         = BIT(6),
 
 	/* IMPORTANT: Below are all the legacy flags, add new ones above. */
 

include/uapi/drm/drm.h

···
 #define DRM_CAP_PAGE_FLIP_TARGET	0x11
 #define DRM_CAP_CRTC_IN_VBLANK_EVENT	0x12
 #define DRM_CAP_SYNCOBJ		0x13
+#define DRM_CAP_SYNCOBJ_TIMELINE	0x14
 
 /** DRM_IOCTL_GET_CAP ioctl argument type */
 struct drm_get_cap {