drm/i915/dp_mst: Force modeset CRTC if DSC toggling requires it

Enabling / disabling DSC decompression in the branch device downstream
of the source may reset the whole branch device. To avoid this while the
streams are still active, force a modeset on all CRTC/ports connected to
this branch device.

v2:
- Check the CRTC state for each connector in the topology, instead of
  the CRTC being checked for a modeset requirement. (Ville)
- Add DocBook for the new function.
v3:
- Rebased on a change not to use
  intel_modeset_pipes_in_mask_early().

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> (v1)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231107001505.3370108-8-imre.deak@intel.com

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h b/drivers/gpu/drm/i915/display/intel_dp_mst.h
index f1815bb72267..fc5e85776a85 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.h
@@ -22,5 +22,7 @@ bool intel_dp_mst_is_slave_trans(const struct intel_crtc_state *crtc_state);
 bool intel_dp_mst_source_support(struct intel_dp *intel_dp);
 int intel_dp_mst_add_topology_state_for_crtc(struct intel_atomic_state *state,
 					     struct intel_crtc *crtc);
+bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state,
+				     struct intel_crtc *crtc);
 
 #endif /* __INTEL_DP_MST_H__ */