We would scan out the memory around them if an upscale was attempted,
and would just scan out incorrectly for downscaling.
Signed-off-by: Eric Anholt <eric at anholt.net>
---
It looks like, while modetest only wants to set scaling on overlay
planes, one could do so on our primary/cursor planes if the fd was in
universal planes mode.
drivers/gpu/drm/vc4/vc4_plane.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index 2db5092..887f3ca 100644
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -157,6 +157,16 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
int crtc_w = state->crtc_w;
int crtc_h = state->crtc_h;
+ if (state->crtc_w << 16 != state->src_w ||
+ state->crtc_h << 16 != state->src_h) {
+ /* We don't support scaling yet, which involves
+ * allocating the LBM memory for scaling temporary
+ * storage, and putting filter kernels in the HVS
+ * context.
+ */
+ return -EINVAL;
+ }
+
if (crtc_x < 0) {
offset += drm_format_plane_cpp(fb->pixel_format, 0) * -crtc_x;
crtc_w += crtc_x;
--
2.6.1
