[AMD Public Use]
> -----Original Message-----
> From: Lyude Paul <lyude@xxxxxxxxxx>
> Sent: Wednesday, January 15, 2020 5:19 AM
> To: Lin, Wayne <Wayne.Lin@xxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx;
> amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: Kazlauskas, Nicholas <Nicholas.Kazlauskas@xxxxxxx>; Wentland, Harry
> <Harry.Wentland@xxxxxxx>; Zuo, Jerry <Jerry.Zuo@xxxxxxx>; Ville Syrjälä
> <ville.syrjala@xxxxxxxxxxxxxxx>; Wentland, Harry <Harry.Wentland@xxxxxxx>
> Subject: Re: [PATCH 2/2] drm/dp_mst: Handle SST-only branch device case
>
> On Wed, 2020-01-08 at 16:44 +0800, Wayne Lin wrote:
> > [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:
> > - 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()
> >
> > Fixes: c485e2c97dae ("drm/dp_mst: Refactor pdt setup/teardown, add
> > more
> > locking")
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Harry Wentland <hwentlan@xxxxxxx>
> > Cc: Lyude Paul <lyude@xxxxxxxxxx>
> > Signed-off-by: Wayne Lin <Wayne.Lin@xxxxxxx>
> > ---
> > drivers/gpu/drm/drm_dp_mst_topology.c | 131
> > +++++++++++++-------------
> > 1 file changed, 68 insertions(+), 63 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> > b/drivers/gpu/drm/drm_dp_mst_topology.c
> > index 8f54b241db08..4395d5cc0645 100644
> > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > @@ -1934,73 +1934,74 @@ static bool
> drm_dp_mst_is_dp_mst_end_device(u8
> > pdt, bool mcs)
> > return true;
> > }
> >
> > -static int drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8
> > new_pdt)
> > +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:
> > @@ -2153,12 +2154,12 @@ 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) {
> > - port->cached_edid = drm_get_edid(port->connector,
> > - &port->aux.ddc);
> > - drm_connector_set_tile_property(port->connector);
> > + if (port->pdt != DP_PEER_DEVICE_NONE) {
> > + if (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);
> > + }
>
> I'd combine these two if statements here into one, otherwise this looks great.
> Thank you for all of the great fixes recently :)
>
> Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
Thanks for your time!
I will fix it in the new version.
Thanks.
>
>
> > }
> >
> > mgr->cbs->register_connector(port->connector);
> > @@ -2223,6 +2224,7 @@ 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); @@ -2267,7
> > +2269,7 @@ 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; @@ -2295,7 +2297,7 @@
> > 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) {
> > @@ -2309,7 +2311,8 @@ 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)
> > @@ -2346,6 +2349,7 @@ 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); @@ -2377,7
> > +2381,6 @@ 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;
> >
> > @@ -2390,8 +2393,8 @@ 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) {
> > @@ -3958,6 +3961,8 @@ 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:
> > @@ -4597,7 +4602,7 @@ 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);
> > }
> >
> --
> Cheers,
> Lyude Paul
--
Best regards,
Wayne Lin
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