* actual modifier used if the request doesn't have it specified,
* ie. when (@mode_cmd->flags & DRM_MODE_FB_MODIFIERS) == 0.
*
+ * IMPORTANT: These implied modifiers for legacy userspace must be
+ * stored in struct &drm_framebuffer, including all relevant metadata
+ * like &drm_framebuffer.pitches and &drm_framebuffer.offsets if the
+ * modifier enables additional planes beyond the fourcc pixel format
+ * code. This is required by the GETFB2 ioctl.
+ *
* If the parameters are deemed valid and the backing storage objects in
* the underlying memory manager all exist, then the driver allocates
* a new &drm_framebuffer structure, subclassed to contain
* @allow_fb_modifiers:
*
* Whether the driver supports fb modifiers in the ADDFB2.1 ioctl call.
+ *
+ * IMPORTANT:
+ *
+ * If this is set the driver must fill out the full implicit modifier
+ * information in their &drm_mode_config_funcs.fb_create hook for legacy
+ * userspace which does not set modifiers. Otherwise the GETFB2 ioctl is
+ * broken for modifier aware userspace.
*/
bool allow_fb_modifiers;