Commit db1a0795 authored by Wayne Lin's avatar Wayne Lin Committed by Lyude Paul
Browse files

drm/dp_mst: Handle SST-only branch device case 

[Why]
While handling LINK_ADDRESS reply, current code expects a peer device
can handle sideband message once the peer device type is reported as
DP_PEER_DEVICE_MST_BRANCHING. However, when the connected device is
a SST branch case, it can't handle the sideband message(MST_CAP=0 in
DPCD 00021h).

Current code will try to send LINK_ADDRESS to SST branch device and end
up with message timeout and monitor can't display normally. As the
result of that, we should take SST branch device into account.

[How]
According to DP 1.4 spec, we can use Peer_Device_Type as
DP_PEER_DEVICE_MST_BRANCHING and Message_Capability_Status as 0 to
indicate peer device as a SST-only branch device.

Fix following:
- Add the function drm_dp_mst_is_dp_mst_end_device() to decide whether a
peer device connected to a DFP is mst end device. Which also indicates
if the peer device is capable of handling message or not.
- Take SST-only branch device case into account in
drm_dp_port_set_pdt() and add a new parameter 'new_mcs'. Take sst branch
device case as the same case as DP_PEER_DEVICE_DP_LEGACY_CONV and
DP_PEER_DEVICE_SST_SINK. All original handling logics remain.
- Take SST-only branch device case into account in
drm_dp_mst_port_add_connector().
- Fix some parts in drm_dp_mst_handle_link_address_port() to have SST
branch device case into consideration.
- Fix the arguments of drm_dp_port_set_pdt() in
drm_dp_mst_handle_conn_stat().
- Have SST branch device also report
connector_status_connected when the ddps is true
in drm_dp_mst_detect_port()
- Fix the arguments of drm_dp_port_set_pdt() in
drm_dp_delayed_destroy_port()

Changes since v1:(https://patchwork.kernel.org/patch/11323079/

)
* Squash previous patch into one patch and merge the commit message here.
* Combine the if statements mentioned in comments

Fixes: c485e2c9 ("drm/dp_mst: Refactor pdt setup/teardown, add more locking")
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <hwentlan@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Signed-off-by: default avatarWayne Lin <Wayne.Lin@amd.com>
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Signed-off-by: default avatarLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200117060350.26358-2-Wayne.Lin@amd.com
parent 5a64967a

drivers/gpu/drm/drm_dp_mst_topology.c

+80 −60
Original line number Diff line number Diff line
@@ -1916,55 +1916,72 @@ static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port, 
	return parent_lct + 1;

}



static int drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt)

static bool drm_dp_mst_is_dp_mst_end_device(u8 pdt, bool mcs)

{

	switch (pdt) {

	case DP_PEER_DEVICE_DP_LEGACY_CONV:

	case DP_PEER_DEVICE_SST_SINK:

		return true;

	case DP_PEER_DEVICE_MST_BRANCHING:

		/* For sst branch device */

		if (!mcs)

			return true;



		return false;

	}

	return true;

}



static int

drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,

		    bool new_mcs)

{

	struct drm_dp_mst_topology_mgr *mgr = port->mgr;

	struct drm_dp_mst_branch *mstb;

	u8 rad[8], lct;

	int ret = 0;



	if (port->pdt == new_pdt)

	if (port->pdt == new_pdt && port->mcs == new_mcs)

		return 0;



	/* Teardown the old pdt, if there is one */

	switch (port->pdt) {

	case DP_PEER_DEVICE_DP_LEGACY_CONV:

	case DP_PEER_DEVICE_SST_SINK:

	if (port->pdt != DP_PEER_DEVICE_NONE) {

		if (drm_dp_mst_is_dp_mst_end_device(port->pdt, port->mcs)) {

			/*

		 * If the new PDT would also have an i2c bus, don't bother

		 * with reregistering it

			 * If the new PDT would also have an i2c bus,

			 * don't bother with reregistering it

			 */

		if (new_pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||

		    new_pdt == DP_PEER_DEVICE_SST_SINK) {

			if (new_pdt != DP_PEER_DEVICE_NONE &&

			    drm_dp_mst_is_dp_mst_end_device(new_pdt, new_mcs)) {

				port->pdt = new_pdt;

				port->mcs = new_mcs;

				return 0;

			}



			/* remove i2c over sideband */

			drm_dp_mst_unregister_i2c_bus(&port->aux);

		break;

	case DP_PEER_DEVICE_MST_BRANCHING:

		} else {

			mutex_lock(&mgr->lock);

			drm_dp_mst_topology_put_mstb(port->mstb);

			port->mstb = NULL;

			mutex_unlock(&mgr->lock);

		break;

		}

	}



	port->pdt = new_pdt;

	switch (port->pdt) {

	case DP_PEER_DEVICE_DP_LEGACY_CONV:

	case DP_PEER_DEVICE_SST_SINK:

	port->mcs = new_mcs;



	if (port->pdt != DP_PEER_DEVICE_NONE) {

		if (drm_dp_mst_is_dp_mst_end_device(port->pdt, port->mcs)) {

			/* add i2c over sideband */

			ret = drm_dp_mst_register_i2c_bus(&port->aux);

		break;



	case DP_PEER_DEVICE_MST_BRANCHING:

		} else {

			lct = drm_dp_calculate_rad(port, rad);

			mstb = drm_dp_add_mst_branch_device(lct, rad);

			if (!mstb) {

				ret = -ENOMEM;

			DRM_ERROR("Failed to create MSTB for port %p", port);

				DRM_ERROR("Failed to create MSTB for port %p",

					  port);

				goto out;

			}
@@ -1982,7 +1999,7 @@ static int drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt) 


			/* And make sure we send a link address for this */

			ret = 1;

		break;

		}

	}



out:
@@ -2135,9 +2152,8 @@ drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb, 
		goto error;

	}



	if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||

	     port->pdt == DP_PEER_DEVICE_SST_SINK) &&

	    port->port_num >= DP_MST_LOGICAL_PORT_0) {

	if (port->pdt != DP_PEER_DEVICE_NONE &&

	    drm_dp_mst_is_dp_mst_end_device(port->pdt, port->mcs)) {

		port->cached_edid = drm_get_edid(port->connector,

						 &port->aux.ddc);

		drm_connector_set_tile_property(port->connector);
@@ -2201,6 +2217,7 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb, 
	struct drm_dp_mst_port *port;

	int old_ddps = 0, ret;

	u8 new_pdt = DP_PEER_DEVICE_NONE;

	bool new_mcs = 0;

	bool created = false, send_link_addr = false, changed = false;



	port = drm_dp_get_port(mstb, port_msg->port_number);
@@ -2245,7 +2262,7 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb, 
	port->input = port_msg->input_port;

	if (!port->input)

		new_pdt = port_msg->peer_device_type;

	port->mcs = port_msg->mcs;

	new_mcs = port_msg->mcs;

	port->ddps = port_msg->ddps;

	port->ldps = port_msg->legacy_device_plug_status;

	port->dpcd_rev = port_msg->dpcd_revision;
@@ -2272,7 +2289,7 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb, 
		}

	}



	ret = drm_dp_port_set_pdt(port, new_pdt);

	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);

	if (ret == 1) {

		send_link_addr = true;

	} else if (ret < 0) {
@@ -2286,7 +2303,8 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb, 
	 * we're coming out of suspend. In this case, always resend the link

	 * address if there's an MSTB on this port

	 */

	if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING)

	if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&

	    port->mcs)

		send_link_addr = true;



	if (port->connector)
@@ -2323,6 +2341,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, 
	struct drm_dp_mst_port *port;

	int old_ddps, old_input, ret, i;

	u8 new_pdt;

	bool new_mcs;

	bool dowork = false, create_connector = false;



	port = drm_dp_get_port(mstb, conn_stat->port_number);
@@ -2354,7 +2373,6 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, 
	old_ddps = port->ddps;

	old_input = port->input;

	port->input = conn_stat->input_port;

	port->mcs = conn_stat->message_capability_status;

	port->ldps = conn_stat->legacy_device_plug_status;

	port->ddps = conn_stat->displayport_device_plug_status;
@@ -2367,8 +2385,8 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, 
	}



	new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;



	ret = drm_dp_port_set_pdt(port, new_pdt);

	new_mcs = conn_stat->message_capability_status;

	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);

	if (ret == 1) {

		dowork = true;

	} else if (ret < 0) {
@@ -3929,6 +3947,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector, 
	switch (port->pdt) {

	case DP_PEER_DEVICE_NONE:

	case DP_PEER_DEVICE_MST_BRANCHING:

		if (!port->mcs)

			ret = connector_status_connected;

		break;



	case DP_PEER_DEVICE_SST_SINK:
@@ -4541,7 +4561,7 @@ drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port) 
	if (port->connector)

		port->mgr->cbs->destroy_connector(port->mgr, port->connector);



	drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE);

	drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);

	drm_dp_mst_put_port_malloc(port);

}

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