[Nouveau] [PATCH] nouveau/dispnv50: add cursor size/pitch checks

[Simon Ser]

The hardware needs a FB which is packed and not too large. Add
checks to make sure this is the case.

While at it, add a debug log for the existing check. This allows
user-space to more easily figure out why a configuration is
rejected.

This commit depends on "drm/nouveau/kms/nv50-: Report max cursor
size to userspace", otherwise mode_config.cursor_{width,height}
is zero.

Signed-off-by: Simon Ser <contact at emersion.fr>
Cc: Lyude Paul <lyude at redhat.com>
Cc: Ben Skeggs <bskeggs at redhat.com>
Cc: Ilia Mirkin <imirkin at alum.mit.edu>
---
 drivers/gpu/drm/nouveau/dispnv50/curs507a.c | 22 ++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/curs507a.c b/drivers/gpu/drm/nouveau/dispnv50/curs507a.c
index 54fbd6fe751d..9a401751c56d 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/curs507a.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/curs507a.c
@@ -99,6 +99,7 @@ curs507a_acquire(struct nv50_wndw *wndw, struct nv50_wndw_atom *asyw,
 		 struct nv50_head_atom *asyh)
 {
 	struct nv50_head *head = nv50_head(asyw->state.crtc);
+	struct drm_device *dev = head->base.base.dev;
 	int ret;
 
 	ret = drm_atomic_helper_check_plane_state(&asyw->state, &asyh->state,
@@ -109,8 +110,27 @@ curs507a_acquire(struct nv50_wndw *wndw, struct nv50_wndw_atom *asyw,
 	if (ret || !asyh->curs.visible)
 		return ret;
 
-	if (asyw->image.w != asyw->image.h)
+	if (asyw->image.w != asyw->image.h) {
+		drm_dbg_atomic(dev,
+			       "Invalid cursor image size: width (%d) must match height (%d)",
+			       asyw->image.w, asyw->image.h);
 		return -EINVAL;
+	}
+	if (asyw->image.w > dev->mode_config.cursor_width ||
+	    asyw->image.h > dev->mode_config.cursor_height) {
+		drm_dbg_atomic(dev,
+			       "Invalid cursor image size: too large (%dx%d > %dx%d)",
+			       asyw->image.w, asyw->image.h,
+			       dev->mode_config.cursor_width,
+			       dev->mode_config.cursor_height);
+		return -EINVAL;
+	}
+	if (asyw->image.pitch[0] != asyw->image.w * 4) {
+		drm_dbg_atomic(dev,
+			       "Invalid cursor image pitch: image must be packed (pitch = %d, width = %d)",
+			       asyw->image.pitch[0], asyw->image.w);
+		return -EINVAL;
+	}
 
 	ret = head->func->curs_layout(head, asyw, asyh);
 	if (ret)
-- 
2.30.0