On Fri, 23 Aug 2019, David Francis <[email protected]> wrote: > Add drm_dp_mst_dsc_aux_for_port. To enable DSC, the DSC_ENABLED > register might have to be written on the leaf port's DPCD, > its parent's DPCD, or the MST manager's DPCD. This function > finds the correct aux for the job. > > As part of this, add drm_dp_mst_is_virtual_dpcd. Virtual DPCD > is a DP feature new in DP v1.4, which exposes certain DPCD > registers on virtual ports. > > ALso add a new quirk for Synatics MST hubs that support DSC > despite not supporting virtual DPCD.
"Also" in the commit message often means, "should be a separate patch". I think this is true here. BR, Jani. > > Cc: Lyude Paul <[email protected]> > Cc: Wenjing Liu <[email protected]> > Cc: Nikola Cornij <[email protected]> > Signed-off-by: David Francis <[email protected]> > --- > drivers/gpu/drm/drm_dp_helper.c | 2 + > drivers/gpu/drm/drm_dp_mst_topology.c | 147 ++++++++++++++++++++++++++ > include/drm/drm_dp_helper.h | 7 ++ > include/drm/drm_dp_mst_helper.h | 2 + > 4 files changed, 158 insertions(+) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index 2cc21eff4cf3..fc39323e7d52 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -1270,6 +1270,8 @@ static const struct dpcd_quirk dpcd_quirk_list[] = { > { OUI(0x00, 0x10, 0xfa), DEVICE_ID_ANY, false, > BIT(DP_DPCD_QUIRK_NO_PSR) }, > /* CH7511 seems to leave SINK_COUNT zeroed */ > { OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), > false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) }, > + /* Synaptics DP1.4 MST hubs can support DSC without virtual DPCD */ > + { OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true, > BIT(DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) }, > }; > > #undef OUI > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c > b/drivers/gpu/drm/drm_dp_mst_topology.c > index a39e42c7d868..559bc09b6b94 100644 > --- a/drivers/gpu/drm/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c > @@ -4150,3 +4150,150 @@ static void drm_dp_mst_unregister_i2c_bus(struct > drm_dp_aux *aux) > { > i2c_del_adapter(&aux->ddc); > } > + > +/** > + * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device > + * @port: The port to check > + * > + * A single physical MST hub object can be represented in the topology > + * by multiple branches, with virtual ports between those branches. > + * > + * As of DP1.4, An MST hub with internal (virtual) ports must expose > + * certain DPCD registers over those ports. See sections 2.6.1.1.1 > + * and 2.6.1.1.2 of Display Port specification v1.4 for details. > + * > + * May acquire mgr->lock > + * > + * Returns: > + * true if the port is a virtual DP peer device, false otherwise > + */ > +static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port) > +{ > + struct drm_dp_mst_port *downstream_port; > + > + if (!port) > + return false; > + > + /* Virtual DP Sink (Internal Display Panel) */ > + if (port->port_num >= 8 && port->dpcd_rev >= DP_DPCD_REV_14) > + return true; > + > + /* DP-to-HDMI Protocol Converter */ > + if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV && > + !port->mcs && > + port->ldps && > + port->dpcd_rev >= DP_DPCD_REV_14) > + return true; > + > + /* DP-to-DP */ > + mutex_lock(&port->mgr->lock); > + if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING && > + port->mstb && > + port->dpcd_rev >= DP_DPCD_REV_14 && > + port->mstb->num_ports == 2) { > + list_for_each_entry(downstream_port, &port->mstb->ports, next) { > + if (!downstream_port->input && > + downstream_port->pdt == DP_PEER_DEVICE_SST_SINK) > + return true; > + } > + } > + mutex_unlock(&port->mgr->lock); > + > + return false; > +} > + > +/** > + * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC > + * @port: The port to check. A leaf of the MST tree with an attached display. > + * > + * Depending on the situation, DSC may be enabled via the endpoint aux, > + * the immediately upstream aux, or the connector's physical aux. > + * > + * This is both the correct aux to read DSC_CAPABILITY and the > + * correct aux to write DSC_ENABLED. > + * > + * This operation can be expensive (up to four aux reads), so > + * the caller should cache the return. > + * > + * Returns: > + * NULL if DSC cannot be enabled on this port, otherwise the aux device > + */ > +struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port) > +{ > + struct drm_dp_mst_port *immediate_upstream_port; > + struct drm_dp_mst_port *fec_port; > + struct drm_dp_desc *desc; > + > + if (port && port->parent) > + immediate_upstream_port = port->parent->port_parent; > + else > + immediate_upstream_port = NULL; > + > + fec_port = immediate_upstream_port; > + while (fec_port) { > + /* > + * Each physical link (i.e. not a virtual port) between the > + * output and the primary device must support FEC > + */ > + if (!drm_dp_mst_is_virtual_dpcd(fec_port) && > + !fec_port->fec_capable) > + return NULL; > + > + fec_port = fec_port->parent->port_parent; > + } > + > + /* Enpoint decompression with DP-to-DP peer device */ > + if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) { > + u8 upstream_dsc; > + u8 endpoint_dsc; > + u8 endpoint_fec; > + > + if (drm_dp_dpcd_read(&port->aux, > + DP_DSC_SUPPORT, &endpoint_dsc, 1) < 0) > + return NULL; > + if (drm_dp_dpcd_read(&port->aux, > + DP_FEC_CAPABILITY, &endpoint_fec, 1) < 0) > + return NULL; > + if (drm_dp_dpcd_read(&immediate_upstream_port->aux, > + DP_DSC_SUPPORT, &upstream_dsc, 1) < 0) > + return NULL; > + > + if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) > + && (endpoint_fec & DP_FEC_CAPABLE) > + && (upstream_dsc & 0x2) /* DSC passthrough */) > + return &port->aux; > + > + /* Virtual DPCD decompression with DP-to-DP peer device */ > + return &immediate_upstream_port->aux; > + } > + > + /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */ > + if (drm_dp_mst_is_virtual_dpcd(port)) > + return &port->aux; > + > + /* > + * Synaptics quirk > + * Applies to ports for which: > + * - Physical aux has Synaptics OUI > + * - DPv1.4 or higher > + * - Port is on primary branch device > + * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG) > + */ > + drm_dp_read_desc(port->mgr->aux, desc, true); > + if (drm_dp_has_quirk(desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD && > + port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14) && > + port->parent == port->mgr->mst_primary) { > + u8 downstreamport; > + > + drm_dp_dpcd_read(&port->aux, DP_DOWNSTREAMPORT_PRESENT, > + &downstreamport, 1); > + > + if ((downstreamport & DP_DWN_STRM_PORT_PRESENT) && > + (downstreamport & DP_DWN_STRM_PORT_TYPE_MASK > + != DP_DWN_STRM_PORT_TYPE_ANALOG)) > + return port->mgr->aux; > + } > + > + return NULL; > +} > +EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port); > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index 8364502f92cf..a1331b08705f 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -1434,6 +1434,13 @@ enum drm_dp_quirk { > * The driver should ignore SINK_COUNT during detection. > */ > DP_DPCD_QUIRK_NO_SINK_COUNT, > + /** > + * @DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD: > + * > + * The device supports MST DSC despite not supporting Virtual DPCD. > + * The DSC caps can be read from the physical aux instead. > + */ > + DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD, > }; > > /** > diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h > index f113ae04fa88..4cf738545dfb 100644 > --- a/include/drm/drm_dp_mst_helper.h > +++ b/include/drm/drm_dp_mst_helper.h > @@ -673,6 +673,8 @@ int __must_check drm_dp_mst_atomic_check(struct > drm_atomic_state *state); > void drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port); > void drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port); > > +struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port); > + > extern const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs; > > /** -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
