drm_atomic_helper_check_modeset — validate state object for modeset changes
int drm_atomic_helper_check_modeset ( | struct drm_device * dev, |
struct drm_atomic_state * state); |
Check the state object to see if the requested state is physically possible. This does all the crtc and connector related computations for an atomic update. It computes and updates crtc_state->mode_changed, adds any additional connectors needed for full modesets and calls down into ->mode_fixup functions of the driver backend.
Drivers which update ->mode_changed (e.g. in their ->atomic_check hooks if a plane update can't be done without a full modeset) _must_ call this function afterwards after that change. It is permitted to call this function multiple times for the same update, e.g. when the ->atomic_check functions depend upon the adjusted dotclock for fifo space allocation and watermark computation.
RETURNS Zero for success or -errno