[PATCH v2 0/2] Fix observed mst problems with StarTech hub

[PATCH v2 0/2] Fix observed mst problems with StarTech hub

[Wayne Lin]

Use Startech 1to3 DP hub to do some mst hotplug tests and find some
light up issues.

1. ACT polling timeout:
   Which is due to we didn't update DPCD payload table but still try
   to send ACT and polling for "ACT Handled" bit
2. Not all monitors light up:
   Due to we wrongly set unavailable VCP ID for new streams

Changes since v1:
* Add appropriate tags: Fixes & Cc
* Change debug macro to use drm_dbg_kms() instead

Wayne Lin (2):
  drm/dp_mst: Do not set proposed vcpi directly
  drm/dp_mst: Avoid to mess up payload table by ports in stale topology

 drivers/gpu/drm/drm_dp_mst_topology.c | 65 ++++++++++++++++-----------
 1 file changed, 39 insertions(+), 26 deletions(-)

-- 
2.17.1

[PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly

[Wayne Lin]

[Why]
When we receive CSN message to notify one port is disconnected, we will
implicitly set its corresponding num_slots to 0. Later on, we will
eventually call drm_dp_update_payload_part1() to arrange down streams.

In drm_dp_update_payload_part1(), we iterate over all proposed_vcpis[]
to do the update. Not specific to a target sink only. For example, if we
light up 2 monitors, Monitor_A and Monitor_B, and then we unplug
Monitor_B. Later on, when we call drm_dp_update_payload_part1() to try
to update payload for Monitor_A, we'll also implicitly clean payload for
Monitor_B at the same time. And finally, when we try to call
drm_dp_update_payload_part1() to clean payload for Monitor_B, we will do
nothing at this time since payload for Monitor_B has been cleaned up
previously.

For StarTech 1to3 DP hub, it seems like if we didn't update DPCD payload
ID table then polling for "ACT Handled"(BIT_1 of DPCD 002C0h) will fail
and this polling will last for 3 seconds.

Therefore, guess the best way is we don't set the proposed_vcpi[]
diretly. Let user of these herlper functions to set the proposed_vcpi
directly.

[How]
1. Revert commit 7617e9621bf2 ("drm/dp_mst: clear time slots for ports
invalid")
2. Tackle the issue in previous commit by skipping those trasient
proposed VCPIs. These stale VCPIs shoulde be explicitly cleared by
user later on.

Changes since v1:
* Change debug macro to use drm_dbg_kms() instead
* Amend the commit message to add Fixed & Cc tags

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Fixes: 7617e9621bf2 ("drm/dp_mst: clear time slots for ports invalid")
Cc: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.5+
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 36 ++++++++-------------------
 1 file changed, 10 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 32b7f8983b94..b41b837db66d 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2501,7 +2501,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
 {
 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
 	struct drm_dp_mst_port *port;
-	int old_ddps, old_input, ret, i;
+	int old_ddps, ret;
 	u8 new_pdt;
 	bool new_mcs;
 	bool dowork = false, create_connector = false;
@@ -2533,7 +2533,6 @@ 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->ldps = conn_stat->legacy_device_plug_status;
 	port->ddps = conn_stat->displayport_device_plug_status;
@@ -2555,28 +2554,6 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
 		dowork = false;
 	}
 
-	if (!old_input && old_ddps != port->ddps && !port->ddps) {
-		for (i = 0; i < mgr->max_payloads; i++) {
-			struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
-			struct drm_dp_mst_port *port_validated;
-
-			if (!vcpi)
-				continue;
-
-			port_validated =
-				container_of(vcpi, struct drm_dp_mst_port, vcpi);
-			port_validated =
-				drm_dp_mst_topology_get_port_validated(mgr, port_validated);
-			if (!port_validated) {
-				mutex_lock(&mgr->payload_lock);
-				vcpi->num_slots = 0;
-				mutex_unlock(&mgr->payload_lock);
-			} else {
-				drm_dp_mst_topology_put_port(port_validated);
-			}
-		}
-	}
-
 	if (port->connector)
 		drm_modeset_unlock(&mgr->base.lock);
 	else if (create_connector)
@@ -3410,8 +3387,15 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 				port = drm_dp_mst_topology_get_port_validated(
 				    mgr, port);
 				if (!port) {
-					mutex_unlock(&mgr->payload_lock);
-					return -EINVAL;
+					if (vcpi->num_slots == payload->num_slots) {
+						cur_slots += vcpi->num_slots;
+						payload->start_slot = req_payload.start_slot;
+						continue;
+					} else {
+						drm_dbg_kms("Fail:set payload to invalid sink");
+						mutex_unlock(&mgr->payload_lock);
+						return -EINVAL;
+					}
 				}
 				put_port = true;
 			}
-- 
2.17.1

[PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly

[Wayne Lin]

[Why]
When we receive CSN message to notify one port is disconnected, we will
implicitly set its corresponding num_slots to 0. Later on, we will
eventually call drm_dp_update_payload_part1() to arrange down streams.

In drm_dp_update_payload_part1(), we iterate over all proposed_vcpis[]
to do the update. Not specific to a target sink only. For example, if we
light up 2 monitors, Monitor_A and Monitor_B, and then we unplug
Monitor_B. Later on, when we call drm_dp_update_payload_part1() to try
to update payload for Monitor_A, we'll also implicitly clean payload for
Monitor_B at the same time. And finally, when we try to call
drm_dp_update_payload_part1() to clean payload for Monitor_B, we will do
nothing at this time since payload for Monitor_B has been cleaned up
previously.

For StarTech 1to3 DP hub, it seems like if we didn't update DPCD payload
ID table then polling for "ACT Handled"(BIT_1 of DPCD 002C0h) will fail
and this polling will last for 3 seconds.

Therefore, guess the best way is we don't set the proposed_vcpi[]
diretly. Let user of these herlper functions to set the proposed_vcpi
directly.

[How]
1. Revert commit 7617e9621bf2 ("drm/dp_mst: clear time slots for ports
invalid")
2. Tackle the issue in previous commit by skipping those trasient
proposed VCPIs. These stale VCPIs shoulde be explicitly cleared by
user later on.

Changes since v1:
* Change debug macro to use drm_dbg_kms() instead
* Amend the commit message to add Fixed & Cc tags

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Fixes: 7617e9621bf2 ("drm/dp_mst: clear time slots for ports invalid")
Cc: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.5+
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 36 ++++++++-------------------
 1 file changed, 10 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 32b7f8983b94..b41b837db66d 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2501,7 +2501,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
 {
 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
 	struct drm_dp_mst_port *port;
-	int old_ddps, old_input, ret, i;
+	int old_ddps, ret;
 	u8 new_pdt;
 	bool new_mcs;
 	bool dowork = false, create_connector = false;
@@ -2533,7 +2533,6 @@ 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->ldps = conn_stat->legacy_device_plug_status;
 	port->ddps = conn_stat->displayport_device_plug_status;
@@ -2555,28 +2554,6 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
 		dowork = false;
 	}
 
-	if (!old_input && old_ddps != port->ddps && !port->ddps) {
-		for (i = 0; i < mgr->max_payloads; i++) {
-			struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
-			struct drm_dp_mst_port *port_validated;
-
-			if (!vcpi)
-				continue;
-
-			port_validated =
-				container_of(vcpi, struct drm_dp_mst_port, vcpi);
-			port_validated =
-				drm_dp_mst_topology_get_port_validated(mgr, port_validated);
-			if (!port_validated) {
-				mutex_lock(&mgr->payload_lock);
-				vcpi->num_slots = 0;
-				mutex_unlock(&mgr->payload_lock);
-			} else {
-				drm_dp_mst_topology_put_port(port_validated);
-			}
-		}
-	}
-
 	if (port->connector)
 		drm_modeset_unlock(&mgr->base.lock);
 	else if (create_connector)
@@ -3410,8 +3387,15 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 				port = drm_dp_mst_topology_get_port_validated(
 				    mgr, port);
 				if (!port) {
-					mutex_unlock(&mgr->payload_lock);
-					return -EINVAL;
+					if (vcpi->num_slots == payload->num_slots) {
+						cur_slots += vcpi->num_slots;
+						payload->start_slot = req_payload.start_slot;
+						continue;
+					} else {
+						drm_dbg_kms("Fail:set payload to invalid sink");
+						mutex_unlock(&mgr->payload_lock);
+						return -EINVAL;
+					}
 				}
 				put_port = true;
 			}
-- 
2.17.1

[PATCH v2 2/2] drm/dp_mst: Avoid to mess up payload table by ports in stale topology

[Wayne Lin]

[Why]
After unplug/hotplug hub from the system, userspace might start to
clear stale payloads gradually. If we call drm_dp_mst_deallocate_vcpi()
to release stale VCPI of those ports which are not relating to current
topology, we have chane to wrongly clear active payload table entry for
current topology.

E.g.
We have allocated VCPI 1 in current payload table and we call
drm_dp_mst_deallocate_vcpi() to clean VCPI 1 in stale topology. In
drm_dp_mst_deallocate_vcpi(), it will call drm_dp_mst_put_payload_id()
tp put VCPI 1 and which means ID 1 is available again. Thereafter, if we
want to allocate a new payload stream, it will find ID 1 is available by
drm_dp_mst_assign_payload_id(). However, ID 1 is being used

[How]
Check target sink is relating to current topology or not before doing
any payload table update.
Searching upward to find the target sink's relevant root branch device.
If the found root branch device is not the same root of current
topology, don't update payload table.

Changes since v1:
* Change debug macro to use drm_dbg_kms() instead
* Amend the commit message to add Cc tag.

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 29 +++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index b41b837db66d..9ac148efd9e4 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -94,6 +94,9 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
 
+static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
+						 struct drm_dp_mst_branch *branch);
+
 #define DBG_PREFIX "[dp_mst]"
 
 #define DP_STR(x) [DP_ ## x] = #x
@@ -3366,6 +3369,7 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 	struct drm_dp_mst_port *port;
 	int i, j;
 	int cur_slots = 1;
+	bool skip;
 
 	mutex_lock(&mgr->payload_lock);
 	for (i = 0; i < mgr->max_payloads; i++) {
@@ -3380,6 +3384,14 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 			port = container_of(vcpi, struct drm_dp_mst_port,
 					    vcpi);
 
+			mutex_lock(&mgr->lock);
+			skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+			mutex_unlock(&mgr->lock);
+
+			if (skip) {
+				drm_dbg_kms("Virtual channel %d is not in current topology\n", i);
+				continue;
+			}
 			/* Validated ports don't matter if we're releasing
 			 * VCPI
 			 */
@@ -3479,6 +3491,7 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
 	struct drm_dp_mst_port *port;
 	int i;
 	int ret = 0;
+	bool skip;
 
 	mutex_lock(&mgr->payload_lock);
 	for (i = 0; i < mgr->max_payloads; i++) {
@@ -3488,6 +3501,13 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
 
 		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
 
+		mutex_lock(&mgr->lock);
+		skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+		mutex_unlock(&mgr->lock);
+
+		if (skip)
+			continue;
+
 		drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
 			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
@@ -4574,9 +4594,18 @@ EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
 				struct drm_dp_mst_port *port)
 {
+	bool skip;
+
 	if (!port->vcpi.vcpi)
 		return;
 
+	mutex_lock(&mgr->lock);
+	skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+	mutex_unlock(&mgr->lock);
+
+	if (skip)
+		return;
+
 	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
 	port->vcpi.num_slots = 0;
 	port->vcpi.pbn = 0;
-- 
2.17.1

[PATCH v2 2/2] drm/dp_mst: Avoid to mess up payload table by ports in stale topology

[Wayne Lin]

[Why]
After unplug/hotplug hub from the system, userspace might start to
clear stale payloads gradually. If we call drm_dp_mst_deallocate_vcpi()
to release stale VCPI of those ports which are not relating to current
topology, we have chane to wrongly clear active payload table entry for
current topology.

E.g.
We have allocated VCPI 1 in current payload table and we call
drm_dp_mst_deallocate_vcpi() to clean VCPI 1 in stale topology. In
drm_dp_mst_deallocate_vcpi(), it will call drm_dp_mst_put_payload_id()
tp put VCPI 1 and which means ID 1 is available again. Thereafter, if we
want to allocate a new payload stream, it will find ID 1 is available by
drm_dp_mst_assign_payload_id(). However, ID 1 is being used

[How]
Check target sink is relating to current topology or not before doing
any payload table update.
Searching upward to find the target sink's relevant root branch device.
If the found root branch device is not the same root of current
topology, don't update payload table.

Changes since v1:
* Change debug macro to use drm_dbg_kms() instead
* Amend the commit message to add Cc tag.

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 29 +++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index b41b837db66d..9ac148efd9e4 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -94,6 +94,9 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
 
+static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
+						 struct drm_dp_mst_branch *branch);
+
 #define DBG_PREFIX "[dp_mst]"
 
 #define DP_STR(x) [DP_ ## x] = #x
@@ -3366,6 +3369,7 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 	struct drm_dp_mst_port *port;
 	int i, j;
 	int cur_slots = 1;
+	bool skip;
 
 	mutex_lock(&mgr->payload_lock);
 	for (i = 0; i < mgr->max_payloads; i++) {
@@ -3380,6 +3384,14 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 			port = container_of(vcpi, struct drm_dp_mst_port,
 					    vcpi);
 
+			mutex_lock(&mgr->lock);
+			skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+			mutex_unlock(&mgr->lock);
+
+			if (skip) {
+				drm_dbg_kms("Virtual channel %d is not in current topology\n", i);
+				continue;
+			}
 			/* Validated ports don't matter if we're releasing
 			 * VCPI
 			 */
@@ -3479,6 +3491,7 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
 	struct drm_dp_mst_port *port;
 	int i;
 	int ret = 0;
+	bool skip;
 
 	mutex_lock(&mgr->payload_lock);
 	for (i = 0; i < mgr->max_payloads; i++) {
@@ -3488,6 +3501,13 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
 
 		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
 
+		mutex_lock(&mgr->lock);
+		skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+		mutex_unlock(&mgr->lock);
+
+		if (skip)
+			continue;
+
 		drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
 			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
@@ -4574,9 +4594,18 @@ EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
 				struct drm_dp_mst_port *port)
 {
+	bool skip;
+
 	if (!port->vcpi.vcpi)
 		return;
 
+	mutex_lock(&mgr->lock);
+	skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+	mutex_unlock(&mgr->lock);
+
+	if (skip)
+		return;
+
 	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
 	port->vcpi.num_slots = 0;
 	port->vcpi.pbn = 0;
-- 
2.17.1

Re: [PATCH v2 2/2] drm/dp_mst: Avoid to mess up payload table by ports in stale topology

[Souza, Jose]

On Wed, 2021-06-16 at 11:55 +0800, Wayne Lin wrote:
> [Why]
> After unplug/hotplug hub from the system, userspace might start to
> clear stale payloads gradually. If we call drm_dp_mst_deallocate_vcpi()
> to release stale VCPI of those ports which are not relating to current
> topology, we have chane to wrongly clear active payload table entry for
> current topology.
> 
> E.g.
> We have allocated VCPI 1 in current payload table and we call
> drm_dp_mst_deallocate_vcpi() to clean VCPI 1 in stale topology. In
> drm_dp_mst_deallocate_vcpi(), it will call drm_dp_mst_put_payload_id()
> tp put VCPI 1 and which means ID 1 is available again. Thereafter, if we
> want to allocate a new payload stream, it will find ID 1 is available by
> drm_dp_mst_assign_payload_id(). However, ID 1 is being used
> 
> [How]
> Check target sink is relating to current topology or not before doing
> any payload table update.
> Searching upward to find the target sink's relevant root branch device.
> If the found root branch device is not the same root of current
> topology, don't update payload table.
> 
> Changes since v1:
> * Change debug macro to use drm_dbg_kms() instead
> * Amend the commit message to add Cc tag.
> 
> Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 29 +++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index b41b837db66d..9ac148efd9e4 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -94,6 +94,9 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
>  static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
>  static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
>  
> +static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
> +						 struct drm_dp_mst_branch *branch);
> +
>  #define DBG_PREFIX "[dp_mst]"
>  
>  #define DP_STR(x) [DP_ ## x] = #x
> @@ -3366,6 +3369,7 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  	struct drm_dp_mst_port *port;
>  	int i, j;
>  	int cur_slots = 1;
> +	bool skip;
>  
>  	mutex_lock(&mgr->payload_lock);
>  	for (i = 0; i < mgr->max_payloads; i++) {
> @@ -3380,6 +3384,14 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  			port = container_of(vcpi, struct drm_dp_mst_port,
>  					    vcpi);
>  
> +			mutex_lock(&mgr->lock);
> +			skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
> +			mutex_unlock(&mgr->lock);
> +
> +			if (skip) {
> +				drm_dbg_kms("Virtual channel %d is not in current topology\n", i);

Missing dev/drm parameter and breaking the build.

> +				continue;
> +			}
>  			/* Validated ports don't matter if we're releasing
>  			 * VCPI
>  			 */
> @@ -3479,6 +3491,7 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
>  	struct drm_dp_mst_port *port;
>  	int i;
>  	int ret = 0;
> +	bool skip;
>  
>  	mutex_lock(&mgr->payload_lock);
>  	for (i = 0; i < mgr->max_payloads; i++) {
> @@ -3488,6 +3501,13 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
>  
>  		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
>  
> +		mutex_lock(&mgr->lock);
> +		skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
> +		mutex_unlock(&mgr->lock);
> +
> +		if (skip)
> +			continue;
> +
>  		drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
>  		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
>  			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
> @@ -4574,9 +4594,18 @@ EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
>  void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
>  				struct drm_dp_mst_port *port)
>  {
> +	bool skip;
> +
>  	if (!port->vcpi.vcpi)
>  		return;
>  
> +	mutex_lock(&mgr->lock);
> +	skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
> +	mutex_unlock(&mgr->lock);
> +
> +	if (skip)
> +		return;
> +
>  	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
>  	port->vcpi.num_slots = 0;
>  	port->vcpi.pbn = 0;

Re: [PATCH v2 2/2] drm/dp_mst: Avoid to mess up payload table by ports in stale topology

[Souza, Jose]

On Wed, 2021-06-16 at 11:55 +0800, Wayne Lin wrote:
> [Why]
> After unplug/hotplug hub from the system, userspace might start to
> clear stale payloads gradually. If we call drm_dp_mst_deallocate_vcpi()
> to release stale VCPI of those ports which are not relating to current
> topology, we have chane to wrongly clear active payload table entry for
> current topology.
> 
> E.g.
> We have allocated VCPI 1 in current payload table and we call
> drm_dp_mst_deallocate_vcpi() to clean VCPI 1 in stale topology. In
> drm_dp_mst_deallocate_vcpi(), it will call drm_dp_mst_put_payload_id()
> tp put VCPI 1 and which means ID 1 is available again. Thereafter, if we
> want to allocate a new payload stream, it will find ID 1 is available by
> drm_dp_mst_assign_payload_id(). However, ID 1 is being used
> 
> [How]
> Check target sink is relating to current topology or not before doing
> any payload table update.
> Searching upward to find the target sink's relevant root branch device.
> If the found root branch device is not the same root of current
> topology, don't update payload table.
> 
> Changes since v1:
> * Change debug macro to use drm_dbg_kms() instead
> * Amend the commit message to add Cc tag.
> 
> Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 29 +++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index b41b837db66d..9ac148efd9e4 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -94,6 +94,9 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
>  static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
>  static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
>  
> +static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
> +						 struct drm_dp_mst_branch *branch);
> +
>  #define DBG_PREFIX "[dp_mst]"
>  
>  #define DP_STR(x) [DP_ ## x] = #x
> @@ -3366,6 +3369,7 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  	struct drm_dp_mst_port *port;
>  	int i, j;
>  	int cur_slots = 1;
> +	bool skip;
>  
>  	mutex_lock(&mgr->payload_lock);
>  	for (i = 0; i < mgr->max_payloads; i++) {
> @@ -3380,6 +3384,14 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  			port = container_of(vcpi, struct drm_dp_mst_port,
>  					    vcpi);
>  
> +			mutex_lock(&mgr->lock);
> +			skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
> +			mutex_unlock(&mgr->lock);
> +
> +			if (skip) {
> +				drm_dbg_kms("Virtual channel %d is not in current topology\n", i);

Missing dev/drm parameter and breaking the build.

> +				continue;
> +			}
>  			/* Validated ports don't matter if we're releasing
>  			 * VCPI
>  			 */
> @@ -3479,6 +3491,7 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
>  	struct drm_dp_mst_port *port;
>  	int i;
>  	int ret = 0;
> +	bool skip;
>  
>  	mutex_lock(&mgr->payload_lock);
>  	for (i = 0; i < mgr->max_payloads; i++) {
> @@ -3488,6 +3501,13 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
>  
>  		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
>  
> +		mutex_lock(&mgr->lock);
> +		skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
> +		mutex_unlock(&mgr->lock);
> +
> +		if (skip)
> +			continue;
> +
>  		drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
>  		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
>  			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
> @@ -4574,9 +4594,18 @@ EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
>  void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
>  				struct drm_dp_mst_port *port)
>  {
> +	bool skip;
> +
>  	if (!port->vcpi.vcpi)
>  		return;
>  
> +	mutex_lock(&mgr->lock);
> +	skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
> +	mutex_unlock(&mgr->lock);
> +
> +	if (skip)
> +		return;
> +
>  	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
>  	port->vcpi.num_slots = 0;
>  	port->vcpi.pbn = 0;

Re: [PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly

[Harry Wentland]

On 2021-06-15 11:55 p.m., Wayne Lin wrote:
> [Why]
> When we receive CSN message to notify one port is disconnected, we will
> implicitly set its corresponding num_slots to 0. Later on, we will
> eventually call drm_dp_update_payload_part1() to arrange down streams.
> 
> In drm_dp_update_payload_part1(), we iterate over all proposed_vcpis[]
> to do the update. Not specific to a target sink only. For example, if we
> light up 2 monitors, Monitor_A and Monitor_B, and then we unplug
> Monitor_B. Later on, when we call drm_dp_update_payload_part1() to try
> to update payload for Monitor_A, we'll also implicitly clean payload for
> Monitor_B at the same time. And finally, when we try to call
> drm_dp_update_payload_part1() to clean payload for Monitor_B, we will do
> nothing at this time since payload for Monitor_B has been cleaned up
> previously.
> 
> For StarTech 1to3 DP hub, it seems like if we didn't update DPCD payload
> ID table then polling for "ACT Handled"(BIT_1 of DPCD 002C0h) will fail
> and this polling will last for 3 seconds.
> 
> Therefore, guess the best way is we don't set the proposed_vcpi[]
> diretly. Let user of these herlper functions to set the proposed_vcpi
> directly.
> 
> [How]
> 1. Revert commit 7617e9621bf2 ("drm/dp_mst: clear time slots for ports
> invalid")
> 2. Tackle the issue in previous commit by skipping those trasient
> proposed VCPIs. These stale VCPIs shoulde be explicitly cleared by
> user later on.
> 
> Changes since v1:
> * Change debug macro to use drm_dbg_kms() instead
> * Amend the commit message to add Fixed & Cc tags
> 
> Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
> Fixes: 7617e9621bf2 ("drm/dp_mst: clear time slots for ports invalid")
> Cc: Lyude Paul <lyude@redhat.com>
> Cc: Wayne Lin <Wayne.Lin@amd.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: dri-devel@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v5.5+
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 36 ++++++++-------------------
>  1 file changed, 10 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 32b7f8983b94..b41b837db66d 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -2501,7 +2501,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
>  {
>  	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
>  	struct drm_dp_mst_port *port;
> -	int old_ddps, old_input, ret, i;
> +	int old_ddps, ret;
>  	u8 new_pdt;
>  	bool new_mcs;
>  	bool dowork = false, create_connector = false;
> @@ -2533,7 +2533,6 @@ 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->ldps = conn_stat->legacy_device_plug_status;
>  	port->ddps = conn_stat->displayport_device_plug_status;
> @@ -2555,28 +2554,6 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
>  		dowork = false;
>  	}
>  
> -	if (!old_input && old_ddps != port->ddps && !port->ddps) {
> -		for (i = 0; i < mgr->max_payloads; i++) {
> -			struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
> -			struct drm_dp_mst_port *port_validated;
> -
> -			if (!vcpi)
> -				continue;
> -
> -			port_validated =
> -				container_of(vcpi, struct drm_dp_mst_port, vcpi);
> -			port_validated =
> -				drm_dp_mst_topology_get_port_validated(mgr, port_validated);
> -			if (!port_validated) {
> -				mutex_lock(&mgr->payload_lock);
> -				vcpi->num_slots = 0;
> -				mutex_unlock(&mgr->payload_lock);
> -			} else {
> -				drm_dp_mst_topology_put_port(port_validated);
> -			}
> -		}
> -	}
> -
>  	if (port->connector)
>  		drm_modeset_unlock(&mgr->base.lock);
>  	else if (create_connector)
> @@ -3410,8 +3387,15 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  				port = drm_dp_mst_topology_get_port_validated(
>  				    mgr, port);
>  				if (!port) {
> -					mutex_unlock(&mgr->payload_lock);
> -					return -EINVAL;
> +					if (vcpi->num_slots == payload->num_slots) {
> +						cur_slots += vcpi->num_slots;
> +						payload->start_slot = req_payload.start_slot;
> +						continue;
> +					} else {
> +						drm_dbg_kms("Fail:set payload to invalid sink");

drm_dbg_kms takes a drm_device as first parameter.

Harry

> +						mutex_unlock(&mgr->payload_lock);
> +						return -EINVAL;
> +					}
>  				}
>  				put_port = true;
>  			}
> 

Re: [PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly

[Harry Wentland]

On 2021-06-15 11:55 p.m., Wayne Lin wrote:
> [Why]
> When we receive CSN message to notify one port is disconnected, we will
> implicitly set its corresponding num_slots to 0. Later on, we will
> eventually call drm_dp_update_payload_part1() to arrange down streams.
> 
> In drm_dp_update_payload_part1(), we iterate over all proposed_vcpis[]
> to do the update. Not specific to a target sink only. For example, if we
> light up 2 monitors, Monitor_A and Monitor_B, and then we unplug
> Monitor_B. Later on, when we call drm_dp_update_payload_part1() to try
> to update payload for Monitor_A, we'll also implicitly clean payload for
> Monitor_B at the same time. And finally, when we try to call
> drm_dp_update_payload_part1() to clean payload for Monitor_B, we will do
> nothing at this time since payload for Monitor_B has been cleaned up
> previously.
> 
> For StarTech 1to3 DP hub, it seems like if we didn't update DPCD payload
> ID table then polling for "ACT Handled"(BIT_1 of DPCD 002C0h) will fail
> and this polling will last for 3 seconds.
> 
> Therefore, guess the best way is we don't set the proposed_vcpi[]
> diretly. Let user of these herlper functions to set the proposed_vcpi
> directly.
> 
> [How]
> 1. Revert commit 7617e9621bf2 ("drm/dp_mst: clear time slots for ports
> invalid")
> 2. Tackle the issue in previous commit by skipping those trasient
> proposed VCPIs. These stale VCPIs shoulde be explicitly cleared by
> user later on.
> 
> Changes since v1:
> * Change debug macro to use drm_dbg_kms() instead
> * Amend the commit message to add Fixed & Cc tags
> 
> Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
> Fixes: 7617e9621bf2 ("drm/dp_mst: clear time slots for ports invalid")
> Cc: Lyude Paul <lyude@redhat.com>
> Cc: Wayne Lin <Wayne.Lin@amd.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: dri-devel@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v5.5+
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 36 ++++++++-------------------
>  1 file changed, 10 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 32b7f8983b94..b41b837db66d 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -2501,7 +2501,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
>  {
>  	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
>  	struct drm_dp_mst_port *port;
> -	int old_ddps, old_input, ret, i;
> +	int old_ddps, ret;
>  	u8 new_pdt;
>  	bool new_mcs;
>  	bool dowork = false, create_connector = false;
> @@ -2533,7 +2533,6 @@ 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->ldps = conn_stat->legacy_device_plug_status;
>  	port->ddps = conn_stat->displayport_device_plug_status;
> @@ -2555,28 +2554,6 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
>  		dowork = false;
>  	}
>  
> -	if (!old_input && old_ddps != port->ddps && !port->ddps) {
> -		for (i = 0; i < mgr->max_payloads; i++) {
> -			struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
> -			struct drm_dp_mst_port *port_validated;
> -
> -			if (!vcpi)
> -				continue;
> -
> -			port_validated =
> -				container_of(vcpi, struct drm_dp_mst_port, vcpi);
> -			port_validated =
> -				drm_dp_mst_topology_get_port_validated(mgr, port_validated);
> -			if (!port_validated) {
> -				mutex_lock(&mgr->payload_lock);
> -				vcpi->num_slots = 0;
> -				mutex_unlock(&mgr->payload_lock);
> -			} else {
> -				drm_dp_mst_topology_put_port(port_validated);
> -			}
> -		}
> -	}
> -
>  	if (port->connector)
>  		drm_modeset_unlock(&mgr->base.lock);
>  	else if (create_connector)
> @@ -3410,8 +3387,15 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  				port = drm_dp_mst_topology_get_port_validated(
>  				    mgr, port);
>  				if (!port) {
> -					mutex_unlock(&mgr->payload_lock);
> -					return -EINVAL;
> +					if (vcpi->num_slots == payload->num_slots) {
> +						cur_slots += vcpi->num_slots;
> +						payload->start_slot = req_payload.start_slot;
> +						continue;
> +					} else {
> +						drm_dbg_kms("Fail:set payload to invalid sink");

drm_dbg_kms takes a drm_device as first parameter.

Harry

> +						mutex_unlock(&mgr->payload_lock);
> +						return -EINVAL;
> +					}
>  				}
>  				put_port = true;
>  			}
> 

Re: [PATCH v2 2/2] drm/dp_mst: Avoid to mess up payload table by ports in stale topology

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 8666 bytes --]

Hi Wayne,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on drm-exynos/exynos-drm-next next-20210616]
[cannot apply to drm-tip/drm-tip tegra-drm/drm/tegra/for-next linus/master drm/drm-next v5.13-rc6]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Wayne-Lin/Fix-observed-mst-problems-with-StarTech-hub/20210617-053552
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: nios2-randconfig-r026-20210617 (attached as .config)
compiler: nios2-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/a904fdf8679b7eb026e3919cd14678ba9a06c8bc
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Wayne-Lin/Fix-observed-mst-problems-with-StarTech-hub/20210617-053552
        git checkout a904fdf8679b7eb026e3919cd14678ba9a06c8bc
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nios2 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from drivers/gpu/drm/drm_dp_mst_topology.c:45:
   drivers/gpu/drm/drm_dp_mst_topology.c: In function 'drm_dp_update_payload_part1':
   include/drm/drm_print.h:450:27: error: request for member 'dev' in something not a structure or union
     450 |  drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_KMS, fmt, ##__VA_ARGS__)
         |                           ^~
   drivers/gpu/drm/drm_dp_mst_topology.c:3392:5: note: in expansion of macro 'drm_dbg_kms'
    3392 |     drm_dbg_kms("Virtual channel %d is not in current topology\n", i);
         |     ^~~~~~~~~~~
>> drivers/gpu/drm/drm_dp_mst_topology.c:3392:68: warning: passing argument 3 of 'drm_dev_dbg' makes pointer from integer without a cast [-Wint-conversion]
    3392 |     drm_dbg_kms("Virtual channel %d is not in current topology\n", i);
         |                                                                    ^
         |                                                                    |
         |                                                                    int
   include/drm/drm_print.h:450:53: note: in definition of macro 'drm_dbg_kms'
     450 |  drm_dev_dbg((drm) ? (drm)->dev : NULL, DRM_UT_KMS, fmt, ##__VA_ARGS__)
         |                                                     ^~~
   include/drm/drm_print.h:338:16: note: expected 'const char *' but argument is of type 'int'
     338 |    const char *format, ...);
         |    ~~~~~~~~~~~~^~~~~~
   drivers/gpu/drm/drm_dp_mst_topology.c:3407:53: error: macro "drm_dbg_kms" requires 3 arguments, but only 1 given
    3407 |       drm_dbg_kms("Fail:set payload to invalid sink");
         |                                                     ^
   In file included from drivers/gpu/drm/drm_dp_mst_topology.c:45:
   include/drm/drm_print.h:449: note: macro "drm_dbg_kms" defined here
     449 | #define drm_dbg_kms(drm, fmt, ...)     \
         | 
   drivers/gpu/drm/drm_dp_mst_topology.c:3407:7: error: 'drm_dbg_kms' undeclared (first use in this function)
    3407 |       drm_dbg_kms("Fail:set payload to invalid sink");
         |       ^~~~~~~~~~~
   drivers/gpu/drm/drm_dp_mst_topology.c:3407:7: note: each undeclared identifier is reported only once for each function it appears in


vim +/drm_dev_dbg +3392 drivers/gpu/drm/drm_dp_mst_topology.c

  3352	
  3353	/**
  3354	 * drm_dp_update_payload_part1() - Execute payload update part 1
  3355	 * @mgr: manager to use.
  3356	 *
  3357	 * This iterates over all proposed virtual channels, and tries to
  3358	 * allocate space in the link for them. For 0->slots transitions,
  3359	 * this step just writes the VCPI to the MST device. For slots->0
  3360	 * transitions, this writes the updated VCPIs and removes the
  3361	 * remote VC payloads.
  3362	 *
  3363	 * after calling this the driver should generate ACT and payload
  3364	 * packets.
  3365	 */
  3366	int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
  3367	{
  3368		struct drm_dp_payload req_payload;
  3369		struct drm_dp_mst_port *port;
  3370		int i, j;
  3371		int cur_slots = 1;
  3372		bool skip;
  3373	
  3374		mutex_lock(&mgr->payload_lock);
  3375		for (i = 0; i < mgr->max_payloads; i++) {
  3376			struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
  3377			struct drm_dp_payload *payload = &mgr->payloads[i];
  3378			bool put_port = false;
  3379	
  3380			/* solve the current payloads - compare to the hw ones
  3381			   - update the hw view */
  3382			req_payload.start_slot = cur_slots;
  3383			if (vcpi) {
  3384				port = container_of(vcpi, struct drm_dp_mst_port,
  3385						    vcpi);
  3386	
  3387				mutex_lock(&mgr->lock);
  3388				skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
  3389				mutex_unlock(&mgr->lock);
  3390	
  3391				if (skip) {
> 3392					drm_dbg_kms("Virtual channel %d is not in current topology\n", i);
  3393					continue;
  3394				}
  3395				/* Validated ports don't matter if we're releasing
  3396				 * VCPI
  3397				 */
  3398				if (vcpi->num_slots) {
  3399					port = drm_dp_mst_topology_get_port_validated(
  3400					    mgr, port);
  3401					if (!port) {
  3402						if (vcpi->num_slots == payload->num_slots) {
  3403							cur_slots += vcpi->num_slots;
  3404							payload->start_slot = req_payload.start_slot;
  3405							continue;
  3406						} else {
  3407							drm_dbg_kms("Fail:set payload to invalid sink");
  3408							mutex_unlock(&mgr->payload_lock);
  3409							return -EINVAL;
  3410						}
  3411					}
  3412					put_port = true;
  3413				}
  3414	
  3415				req_payload.num_slots = vcpi->num_slots;
  3416				req_payload.vcpi = vcpi->vcpi;
  3417			} else {
  3418				port = NULL;
  3419				req_payload.num_slots = 0;
  3420			}
  3421	
  3422			payload->start_slot = req_payload.start_slot;
  3423			/* work out what is required to happen with this payload */
  3424			if (payload->num_slots != req_payload.num_slots) {
  3425	
  3426				/* need to push an update for this payload */
  3427				if (req_payload.num_slots) {
  3428					drm_dp_create_payload_step1(mgr, vcpi->vcpi,
  3429								    &req_payload);
  3430					payload->num_slots = req_payload.num_slots;
  3431					payload->vcpi = req_payload.vcpi;
  3432	
  3433				} else if (payload->num_slots) {
  3434					payload->num_slots = 0;
  3435					drm_dp_destroy_payload_step1(mgr, port,
  3436								     payload->vcpi,
  3437								     payload);
  3438					req_payload.payload_state =
  3439						payload->payload_state;
  3440					payload->start_slot = 0;
  3441				}
  3442				payload->payload_state = req_payload.payload_state;
  3443			}
  3444			cur_slots += req_payload.num_slots;
  3445	
  3446			if (put_port)
  3447				drm_dp_mst_topology_put_port(port);
  3448		}
  3449	
  3450		for (i = 0; i < mgr->max_payloads; /* do nothing */) {
  3451			if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
  3452				i++;
  3453				continue;
  3454			}
  3455	
  3456			drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
  3457			for (j = i; j < mgr->max_payloads - 1; j++) {
  3458				mgr->payloads[j] = mgr->payloads[j + 1];
  3459				mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
  3460	
  3461				if (mgr->proposed_vcpis[j] &&
  3462				    mgr->proposed_vcpis[j]->num_slots) {
  3463					set_bit(j + 1, &mgr->payload_mask);
  3464				} else {
  3465					clear_bit(j + 1, &mgr->payload_mask);
  3466				}
  3467			}
  3468	
  3469			memset(&mgr->payloads[mgr->max_payloads - 1], 0,
  3470			       sizeof(struct drm_dp_payload));
  3471			mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
  3472			clear_bit(mgr->max_payloads, &mgr->payload_mask);
  3473		}
  3474		mutex_unlock(&mgr->payload_lock);
  3475	
  3476		return 0;
  3477	}
  3478	EXPORT_SYMBOL(drm_dp_update_payload_part1);
  3479	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

[-- Attachment #2: config.gz --]
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Re: [PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly

[Lin, Wayne]

[AMD Official Use Only]

________________________________________
> From: Wentland, Harry <Harry.Wentland@amd.com>
> Sent: Thursday, June 17, 2021 03:53
> To: Lin, Wayne; dri-devel@lists.freedesktop.org
> Cc: lyude@redhat.com; Kazlauskas, Nicholas; Zuo, Jerry; Pillai, Aurabindo; Maarten Lankhorst; Maxime Ripard; Thomas Zimmermann; stable@vger.kernel.org
> Subject: Re: [PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly
>
>
>
> On 2021-06-15 11:55 p.m., Wayne Lin wrote:
> > [Why]
> > When we receive CSN message to notify one port is disconnected, we will
> > implicitly set its corresponding num_slots to 0. Later on, we will
> > eventually call drm_dp_update_payload_part1() to arrange down streams.
> >
> > In drm_dp_update_payload_part1(), we iterate over all proposed_vcpis[]
> > to do the update. Not specific to a target sink only. For example, if we
> > light up 2 monitors, Monitor_A and Monitor_B, and then we unplug
> > Monitor_B. Later on, when we call drm_dp_update_payload_part1() to try
> > to update payload for Monitor_A, we'll also implicitly clean payload for
> > Monitor_B at the same time. And finally, when we try to call
> > drm_dp_update_payload_part1() to clean payload for Monitor_B, we will do
> > nothing at this time since payload for Monitor_B has been cleaned up
> > previously.
> >
> > For StarTech 1to3 DP hub, it seems like if we didn't update DPCD payload
> > ID table then polling for "ACT Handled"(BIT_1 of DPCD 002C0h) will fail
> > and this polling will last for 3 seconds.
> >
> > Therefore, guess the best way is we don't set the proposed_vcpi[]
> > diretly. Let user of these herlper functions to set the proposed_vcpi
> > directly.
> >
> > [How]
> > 1. Revert commit 7617e9621bf2 ("drm/dp_mst: clear time slots for ports
> > invalid")
> > 2. Tackle the issue in previous commit by skipping those trasient
> > proposed VCPIs. These stale VCPIs shoulde be explicitly cleared by
> > user later on.
> >
> > Changes since v1:
> > * Change debug macro to use drm_dbg_kms() instead
> > * Amend the commit message to add Fixed & Cc tags
> >
> > Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
> > Fixes: 7617e9621bf2 ("drm/dp_mst: clear time slots for ports invalid")
> > Cc: Lyude Paul <lyude@redhat.com>
> > Cc: Wayne Lin <Wayne.Lin@amd.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Maxime Ripard <mripard@kernel.org>
> > Cc: Thomas Zimmermann <tzimmermann@suse.de>
> > Cc: dri-devel@lists.freedesktop.org
> > Cc: <stable@vger.kernel.org> # v5.5+
> > ---
> >  drivers/gpu/drm/drm_dp_mst_topology.c | 36 ++++++++-------------------
> >  1 file changed, 10 insertions(+), 26 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> > index 32b7f8983b94..b41b837db66d 100644
> > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > @@ -2501,7 +2501,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
> >  {
> >       struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
> >       struct drm_dp_mst_port *port;
> > -     int old_ddps, old_input, ret, i;
> > +     int old_ddps, ret;
> >       u8 new_pdt;
> >       bool new_mcs;
> >       bool dowork = false, create_connector = false;
> > @@ -2533,7 +2533,6 @@ 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->ldps = conn_stat->legacy_device_plug_status;
> >       port->ddps = conn_stat->displayport_device_plug_status;
> > @@ -2555,28 +2554,6 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
> >               dowork = false;
> >       }
> >
> > -     if (!old_input && old_ddps != port->ddps && !port->ddps) {
> > -             for (i = 0; i < mgr->max_payloads; i++) {
> > -                     struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
> > -                     struct drm_dp_mst_port *port_validated;
> > -
> > -                     if (!vcpi)
> > -                             continue;
> > -
> > -                     port_validated =
> > -                             container_of(vcpi, struct drm_dp_mst_port, vcpi);
> > -                     port_validated =
> > -                             drm_dp_mst_topology_get_port_validated(mgr, port_validated);
> > -                     if (!port_validated) {
> > -                             mutex_lock(&mgr->payload_lock);
> > -                             vcpi->num_slots = 0;
> > -                             mutex_unlock(&mgr->payload_lock);
> > -                     } else {
> > -                             drm_dp_mst_topology_put_port(port_validated);
> > -                     }
> > -             }
> > -     }
> > -
> >       if (port->connector)
> >               drm_modeset_unlock(&mgr->base.lock);
> >       else if (create_connector)
> > @@ -3410,8 +3387,15 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
> >                               port = drm_dp_mst_topology_get_port_validated(
> >                                   mgr, port);
> >                               if (!port) {
> > -                                     mutex_unlock(&mgr->payload_lock);
> > -                                     return -EINVAL;
> > +                                     if (vcpi->num_slots == payload->num_slots) {
> > +                                             cur_slots += vcpi->num_slots;
> > +                                             payload->start_slot = req_payload.start_slot;
> > +                                             continue;
> > +                                     } else {
> > +                                             drm_dbg_kms("Fail:set payload to invalid sink");
>
> drm_dbg_kms takes a drm_device as first parameter.
>
> Harry

Thanks Harry. Should be addressed by another patch provided by José.
>
> > +                                             mutex_unlock(&mgr->payload_lock);
> > +                                             return -EINVAL;
> > +                                     }
> >                               }
> >                               put_port = true;
> >                       }
> >
--
Regards,
Wayne

Re: [PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly

[Lin, Wayne]

[AMD Official Use Only]

________________________________________
> From: Wentland, Harry <Harry.Wentland@amd.com>
> Sent: Thursday, June 17, 2021 03:53
> To: Lin, Wayne; dri-devel@lists.freedesktop.org
> Cc: lyude@redhat.com; Kazlauskas, Nicholas; Zuo, Jerry; Pillai, Aurabindo; Maarten Lankhorst; Maxime Ripard; Thomas Zimmermann; stable@vger.kernel.org
> Subject: Re: [PATCH v2 1/2] drm/dp_mst: Do not set proposed vcpi directly
>
>
>
> On 2021-06-15 11:55 p.m., Wayne Lin wrote:
> > [Why]
> > When we receive CSN message to notify one port is disconnected, we will
> > implicitly set its corresponding num_slots to 0. Later on, we will
> > eventually call drm_dp_update_payload_part1() to arrange down streams.
> >
> > In drm_dp_update_payload_part1(), we iterate over all proposed_vcpis[]
> > to do the update. Not specific to a target sink only. For example, if we
> > light up 2 monitors, Monitor_A and Monitor_B, and then we unplug
> > Monitor_B. Later on, when we call drm_dp_update_payload_part1() to try
> > to update payload for Monitor_A, we'll also implicitly clean payload for
> > Monitor_B at the same time. And finally, when we try to call
> > drm_dp_update_payload_part1() to clean payload for Monitor_B, we will do
> > nothing at this time since payload for Monitor_B has been cleaned up
> > previously.
> >
> > For StarTech 1to3 DP hub, it seems like if we didn't update DPCD payload
> > ID table then polling for "ACT Handled"(BIT_1 of DPCD 002C0h) will fail
> > and this polling will last for 3 seconds.
> >
> > Therefore, guess the best way is we don't set the proposed_vcpi[]
> > diretly. Let user of these herlper functions to set the proposed_vcpi
> > directly.
> >
> > [How]
> > 1. Revert commit 7617e9621bf2 ("drm/dp_mst: clear time slots for ports
> > invalid")
> > 2. Tackle the issue in previous commit by skipping those trasient
> > proposed VCPIs. These stale VCPIs shoulde be explicitly cleared by
> > user later on.
> >
> > Changes since v1:
> > * Change debug macro to use drm_dbg_kms() instead
> > * Amend the commit message to add Fixed & Cc tags
> >
> > Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
> > Fixes: 7617e9621bf2 ("drm/dp_mst: clear time slots for ports invalid")
> > Cc: Lyude Paul <lyude@redhat.com>
> > Cc: Wayne Lin <Wayne.Lin@amd.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Maxime Ripard <mripard@kernel.org>
> > Cc: Thomas Zimmermann <tzimmermann@suse.de>
> > Cc: dri-devel@lists.freedesktop.org
> > Cc: <stable@vger.kernel.org> # v5.5+
> > ---
> >  drivers/gpu/drm/drm_dp_mst_topology.c | 36 ++++++++-------------------
> >  1 file changed, 10 insertions(+), 26 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> > index 32b7f8983b94..b41b837db66d 100644
> > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > @@ -2501,7 +2501,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
> >  {
> >       struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
> >       struct drm_dp_mst_port *port;
> > -     int old_ddps, old_input, ret, i;
> > +     int old_ddps, ret;
> >       u8 new_pdt;
> >       bool new_mcs;
> >       bool dowork = false, create_connector = false;
> > @@ -2533,7 +2533,6 @@ 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->ldps = conn_stat->legacy_device_plug_status;
> >       port->ddps = conn_stat->displayport_device_plug_status;
> > @@ -2555,28 +2554,6 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
> >               dowork = false;
> >       }
> >
> > -     if (!old_input && old_ddps != port->ddps && !port->ddps) {
> > -             for (i = 0; i < mgr->max_payloads; i++) {
> > -                     struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
> > -                     struct drm_dp_mst_port *port_validated;
> > -
> > -                     if (!vcpi)
> > -                             continue;
> > -
> > -                     port_validated =
> > -                             container_of(vcpi, struct drm_dp_mst_port, vcpi);
> > -                     port_validated =
> > -                             drm_dp_mst_topology_get_port_validated(mgr, port_validated);
> > -                     if (!port_validated) {
> > -                             mutex_lock(&mgr->payload_lock);
> > -                             vcpi->num_slots = 0;
> > -                             mutex_unlock(&mgr->payload_lock);
> > -                     } else {
> > -                             drm_dp_mst_topology_put_port(port_validated);
> > -                     }
> > -             }
> > -     }
> > -
> >       if (port->connector)
> >               drm_modeset_unlock(&mgr->base.lock);
> >       else if (create_connector)
> > @@ -3410,8 +3387,15 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
> >                               port = drm_dp_mst_topology_get_port_validated(
> >                                   mgr, port);
> >                               if (!port) {
> > -                                     mutex_unlock(&mgr->payload_lock);
> > -                                     return -EINVAL;
> > +                                     if (vcpi->num_slots == payload->num_slots) {
> > +                                             cur_slots += vcpi->num_slots;
> > +                                             payload->start_slot = req_payload.start_slot;
> > +                                             continue;
> > +                                     } else {
> > +                                             drm_dbg_kms("Fail:set payload to invalid sink");
>
> drm_dbg_kms takes a drm_device as first parameter.
>
> Harry

Thanks Harry. Should be addressed by another patch provided by José.
>
> > +                                             mutex_unlock(&mgr->payload_lock);
> > +                                             return -EINVAL;
> > +                                     }
> >                               }
> >                               put_port = true;
> >                       }
> >
--
Regards,
Wayne