drm/vc4: kms: Document the muxing corner cases

	return drmm_add_action_or_reset(&vc4->base, vc4_load_tracker_obj_fini, NULL);

}

/*

 * The BCM2711 HVS has up to 7 outputs connected to the pixelvalves and

 * the TXP (and therefore all the CRTCs found on that platform).

 *

 * The naive (and our initial) implementation would just iterate over

 * all the active CRTCs, try to find a suitable FIFO, and then remove it

 * from the pool of available FIFOs. However, there are a few corner

 * cases that need to be considered:

 *

 * - When running in a dual-display setup (so with two CRTCs involved),

 *   we can update the state of a single CRTC (for example by changing

 *   its mode using xrandr under X11) without affecting the other. In

 *   this case, the other CRTC wouldn't be in the state at all, so we

 *   need to consider all the running CRTCs in the DRM device to assign

 *   a FIFO, not just the one in the state.

 *

 * - Since we need the pixelvalve to be disabled and enabled back when

 *   the FIFO is changed, we should keep the FIFO assigned for as long

 *   as the CRTC is enabled, only considering it free again once that

 *   CRTC has been disabled. This can be tested by booting X11 on a

 *   single display, and changing the resolution down and then back up.

 */

static int vc4_pv_muxing_atomic_check(struct drm_device *dev,

				      struct drm_atomic_state *state)

{