Current implementation of async flip w/a relies on assumption that
previous atomic commit contains valid information if async_flip is still
enabled on the plane. It is incorrect. If previous commit did not modify
the plane its state->uapi.async_flip can be false. As a result DMAR/PIPE
errors can be observed:
i915 0000:00:02.0: [drm] *ERROR* Fault errors on pipe A: 0x00000080
i915 0000:00:02.0: [drm] *ERROR* Fault errors on pipe A: 0x00000080
DMAR: DRHD: handling fault status reg 2
DMAR: [DMA Read NO_PASID] Request device [00:02.0] fault addr 0x0 [fault reason 0x06] PTE Read access is not set

v2: update async_flip_planes in more reliable places (Ville)
v3: reset async_flip_planes and do_async_flip in more scenarios (Ville)
v4: move all resets to plane loops (Ville)
Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230127153003.2225111-1-andrzej.hajda@intel.com