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drm/dp_mst: Handle SST-only branch device case
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[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: c485e2c ("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: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200117060350.26358-2-Wayne.Lin@amd.com
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@Lyude
Wayne Lin authored and Lyude committed Jan 18, 2020
1 parent 5a64967 commit db1a079
Showing 1 changed file with 80 additions and 60 deletions.
140 changes: 80 additions & 60 deletions drivers/gpu/drm/drm_dp_mst_topology.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1916,73 +1916,90 @@ 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 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) {
port->pdt = new_pdt;
return 0;
}
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 (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:
mutex_lock(&mgr->lock);
drm_dp_mst_topology_put_mstb(port->mstb);
port->mstb = NULL;
mutex_unlock(&mgr->lock);
break;
/* remove i2c over sideband */
drm_dp_mst_unregister_i2c_bus(&port->aux);
} else {
mutex_lock(&mgr->lock);
drm_dp_mst_topology_put_mstb(port->mstb);
port->mstb = NULL;
mutex_unlock(&mgr->lock);
}
}

port->pdt = new_pdt;
switch (port->pdt) {
case DP_PEER_DEVICE_DP_LEGACY_CONV:
case DP_PEER_DEVICE_SST_SINK:
/* add i2c over sideband */
ret = drm_dp_mst_register_i2c_bus(&port->aux);
break;
port->mcs = new_mcs;

case DP_PEER_DEVICE_MST_BRANCHING:
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);
goto out;
}
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);
} 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);
goto out;
}

mutex_lock(&mgr->lock);
port->mstb = mstb;
mstb->mgr = port->mgr;
mstb->port_parent = port;
mutex_lock(&mgr->lock);
port->mstb = mstb;
mstb->mgr = port->mgr;
mstb->port_parent = port;

/*
* Make sure this port's memory allocation stays
* around until its child MSTB releases it
*/
drm_dp_mst_get_port_malloc(port);
mutex_unlock(&mgr->lock);
/*
* Make sure this port's memory allocation stays
* around until its child MSTB releases it
*/
drm_dp_mst_get_port_malloc(port);
mutex_unlock(&mgr->lock);

/* And make sure we send a link address for this */
ret = 1;
break;
/* And make sure we send a link address for this */
ret = 1;
}
}

out:
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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) {
Expand All @@ -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)
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;

Expand All @@ -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) {
Expand Down Expand Up @@ -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:
Expand Down Expand Up @@ -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);
}

Expand Down

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