drm/rockchip: vop2: fail cleanly if missing a primary plane for a video-port

[ Upstream commit f9f68bf1d0efeadb6c427c9dbb30f307a7def19b ]

Each window of a vop2 is usable by a specific set of video ports, so while
binding the vop2, we look through the list of available windows trying to
find one designated as primary-plane and usable by that specific port.

The code later wants to use drm_crtc_init_with_planes with that found
primary plane, but nothing has checked so far if a primary plane was
actually found.

For whatever reason, the rk3576 vp2 does not have a usable primary window
(if vp0 is also in use) which brought the issue to light and ended in a
null-pointer dereference further down.

As we expect a primary-plane to exist for a video-port, add a check at
the end of the window-iteration and fail probing if none was found.

Fixes: 604be85547ce ("drm/rockchip: Add VOP2 driver")
Reviewed-by: Andy Yan <andy.yan@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20250610212748.1062375-1-heiko@sntech.de
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
index d0f5fea15e21..6b37ce3ee60b 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
@@ -2422,6 +2422,10 @@ static int vop2_create_crtcs(struct vop2 *vop2)
 				break;
 			}
 		}
+
+		if (!vp->primary_plane)
+			return dev_err_probe(drm->dev, -ENOENT,
+					     "no primary plane for vp %d\n", i);
 	}
 
 	/* Register all unused window as overlay plane */