This patch expands the cursor checks added in "drm/amd/display: add basic
atomic check for cursor plane" to also include a FB size check. Without
this patch, setting a FB smaller than max_cursor_size with an invalid
width would result in amdgpu error messages and a fallback to a 64-byte
width:
    [drm:hubp1_cursor_set_attributes [amdgpu]] *ERROR* Invalid cursor pitch of 100. Only 64/128/256 is supported on DCN.
Note that DC uses the word "pitch" when actually checking the FB width.
Indeed, the function handle_cursor_update does this:
    attributes.pitch = attributes.width;
In my tests, the cursor FB actually had a pitch of 512 bytes.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Simon Ser <contact@emersion.fr>
Reported-by: Pierre-Loup A. Griffais <pgriffais@valvesoftware.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Harry Wentland <hwentlan@amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
                        return -EINVAL;
                }
 
+               if (new_plane_state->fb) {
+                       if (new_plane_state->fb->width > new_acrtc->max_cursor_width ||
+                           new_plane_state->fb->height > new_acrtc->max_cursor_height) {
+                               DRM_DEBUG_ATOMIC("Bad cursor FB size %dx%d\n",
+                                                new_plane_state->fb->width,
+                                                new_plane_state->fb->height);
+                               return -EINVAL;
+                       }
+
+                       switch (new_plane_state->fb->width) {
+                       case 64:
+                       case 128:
+                       case 256:
+                               /* FB width is supported by cursor plane */
+                               break;
+                       default:
+                               DRM_DEBUG_ATOMIC("Bad cursor FB width %d\n",
+                                                new_plane_state->fb->width);
+                               return -EINVAL;
+                       }
+               }
+
                return 0;
        }