On Fri, Oct 27, 2023 at 05:20:10PM +0300, Ville Syrjälä wrote:
> On Tue, Oct 24, 2023 at 04:09:22AM +0300, Imre Deak wrote:
> > Enabling / disabling DSC decompression in the branch device downstream
> > of the source may reset the while branch device. To avoid this while the
> > streams are still active, force a modeset on all CRTC/ports connected to
> > this branch device.
> >
> > Signed-off-by: Imre Deak <imre.d...@intel.com>
> > ---
> > drivers/gpu/drm/i915/display/intel_display.c | 4 ++
> > drivers/gpu/drm/i915/display/intel_dp_mst.c | 72 ++++++++++++++++++++
> > drivers/gpu/drm/i915/display/intel_dp_mst.h | 2 +
> > 3 files changed, 78 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 22f88389035bd..a33e5bbf5165a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -6490,6 +6490,10 @@ int intel_atomic_check(struct drm_device *dev,
> > if (!new_crtc_state->hw.enable ||
> > intel_crtc_needs_modeset(new_crtc_state))
> > continue;
> >
> > + if (intel_dp_mst_crtc_needs_modeset(state, crtc))
> > + intel_modeset_pipes_in_mask_early(state, "MST topology",
> > + BIT(crtc->pipe));
> > +
> > if (intel_dp_mst_is_slave_trans(new_crtc_state)) {
> > enum transcoder master =
> > new_crtc_state->mst_master_transcoder;
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > index 9f4894c2e7860..d4dcfb2c09b2a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > @@ -1606,3 +1606,75 @@ int intel_dp_mst_add_topology_state_for_crtc(struct
> > intel_atomic_state *state,
> >
> > return 0;
> > }
> > +
> > +static struct intel_connector *
> > +get_connector_in_state_for_crtc(struct intel_atomic_state *state,
> > + const struct intel_crtc *crtc)
> > +{
> > + struct drm_connector_state *old_conn_state;
> > + struct drm_connector_state *new_conn_state;
> > + struct drm_connector *_connector;
> > + int i;
> > +
> > + for_each_oldnew_connector_in_state(&state->base, _connector,
> > + old_conn_state, new_conn_state, i) {
> > + struct intel_connector *connector =
> > + to_intel_connector(_connector);
> > +
> > + if (old_conn_state->crtc == &crtc->base ||
> > + new_conn_state->crtc == &crtc->base)
> > + return connector;
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +bool intel_dp_mst_crtc_needs_modeset(struct intel_atomic_state *state,
> > + struct intel_crtc *crtc)
> > +{
> > + const struct intel_connector *crtc_connector;
> > + const struct drm_connector_state *conn_state;
> > + const struct drm_connector *_connector;
> > + int i;
> > +
> > + if (!intel_crtc_has_type(intel_atomic_get_new_crtc_state(state, crtc),
> > + INTEL_OUTPUT_DP_MST))
> > + return false;
> > +
> > + crtc_connector = get_connector_in_state_for_crtc(state, crtc);
> > +
> > + if (!crtc_connector)
> > + /* None of the connectors in the topology needs modeset */
> > + return false;
> > +
> > + for_each_new_connector_in_state(&state->base, _connector, conn_state,
> > i) {
> > + const struct intel_connector *connector =
> > + to_intel_connector(_connector);
> > + const struct intel_crtc_state *new_crtc_state =
> > + intel_atomic_get_new_crtc_state(state, crtc);
> > + const struct intel_crtc_state *old_crtc_state =
> > + intel_atomic_get_old_crtc_state(state, crtc);
>
> What's supposed to be happening here? You're just checking the same
> crtc every time through the loop.
Yes, it's borked, thanks for catching it. It's conn_state->crtc which
should be checked wrt. the change in the compression_enable state.
> > +
> > + if (connector->mst_port != crtc_connector->mst_port)
> > + continue;
> > +
> > + if (!intel_crtc_needs_modeset(new_crtc_state))
> > + continue;
> > +
> > + if (old_crtc_state->dsc.compression_enable ==
> > + new_crtc_state->dsc.compression_enable)
> > + continue;
> > +
> > + /*
> > + * Toggling the compression flag because of this stream in the
> > first
> > + * downstream branch device's UFP DPCD may reset the whole
> > branch
> > + * device. To avoid the reset while other streams are also
> > + * active modeset the whole MST topology in this case.
> > + */
> > + if (connector->dp.dsc_decompression_aux ==
> > + &connector->mst_port->aux)
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.h
> > b/drivers/gpu/drm/i915/display/intel_dp_mst.h
> > index f1815bb722672..fc5e85776a858 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__ */
> > --
> > 2.39.2
>
> --
> Ville Syrjälä
> Intel
