2023-11-16 08:33:06

by Guan-Yu Lin

Subject: [PATCH] usb: typec: tcpm: skip checking port->send_discover in PD3.0

The original Collison Avoidance mechanism, port->send_discover, avoids
the conflict when port partners start AMS almost the same time. However,
this mechanism is replaced by SINK_TX_OK and SINK_TX_NG. Skip the check
in PD3.0 to avoid the deadlock when source is requesting DR_SWAP where
sink is requesting DISCOVER_IDENTITY.

Signed-off-by: Guan-Yu Lin <[email protected]>
---
drivers/usb/typec/tcpm/tcpm.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 058d5b853b57..ff3c171a3a75 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -2847,7 +2847,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
PD_MSG_CTRL_NOT_SUPP,
NONE_AMS);
} else {
- if (port->send_discover) {
+ if (port->send_discover && port->negotiated_rev < PD_REV30) {
tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
break;
}
@@ -2863,7 +2863,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
PD_MSG_CTRL_NOT_SUPP,
NONE_AMS);
} else {
- if (port->send_discover) {
+ if (port->send_discover && port->negotiated_rev < PD_REV30) {
tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
break;
}
@@ -2872,7 +2872,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
}
break;
case PD_CTRL_VCONN_SWAP:
- if (port->send_discover) {
+ if (port->send_discover && port->negotiated_rev < PD_REV30) {
tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
break;
}
--
2.43.0.rc0.421.g78406f8d94-goog

2023-11-21 14:16:47

by Heikki Krogerus

Subject: Re: [PATCH] usb: typec: tcpm: skip checking port->send_discover in PD3.0

On Thu, Nov 16, 2023 at 04:32:16PM +0800, Guan-Yu Lin wrote:
> The original Collison Avoidance mechanism, port->send_discover, avoids
> the conflict when port partners start AMS almost the same time. However,
> this mechanism is replaced by SINK_TX_OK and SINK_TX_NG. Skip the check
> in PD3.0 to avoid the deadlock when source is requesting DR_SWAP where
> sink is requesting DISCOVER_IDENTITY.
>
> Signed-off-by: Guan-Yu Lin <[email protected]>

Reviewed-by: Heikki Krogerus <[email protected]>

> ---
> drivers/usb/typec/tcpm/tcpm.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 058d5b853b57..ff3c171a3a75 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -2847,7 +2847,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
> PD_MSG_CTRL_NOT_SUPP,
> NONE_AMS);
> } else {
> - if (port->send_discover) {
> + if (port->send_discover && port->negotiated_rev < PD_REV30) {
> tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
> break;
> }
> @@ -2863,7 +2863,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
> PD_MSG_CTRL_NOT_SUPP,
> NONE_AMS);
> } else {
> - if (port->send_discover) {
> + if (port->send_discover && port->negotiated_rev < PD_REV30) {
> tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
> break;
> }
> @@ -2872,7 +2872,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
> }
> break;
> case PD_CTRL_VCONN_SWAP:
> - if (port->send_discover) {
> + if (port->send_discover && port->negotiated_rev < PD_REV30) {
> tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
> break;
> }
> --
> 2.43.0.rc0.421.g78406f8d94-goog

--
heikki

2023-11-21 14:48:05

by Guenter Roeck

Subject: Re: [PATCH] usb: typec: tcpm: skip checking port->send_discover in PD3.0

On 11/16/23 00:32, Guan-Yu Lin wrote:
> The original Collison Avoidance mechanism, port->send_discover, avoids
> the conflict when port partners start AMS almost the same time. However,
> this mechanism is replaced by SINK_TX_OK and SINK_TX_NG. Skip the check
> in PD3.0 to avoid the deadlock when source is requesting DR_SWAP where
> sink is requesting DISCOVER_IDENTITY.
>
> Signed-off-by: Guan-Yu Lin <[email protected]>

Reviewed-by: Guenter Roeck <[email protected]>

> ---
> drivers/usb/typec/tcpm/tcpm.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 058d5b853b57..ff3c171a3a75 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -2847,7 +2847,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
> PD_MSG_CTRL_NOT_SUPP,
> NONE_AMS);
> } else {
> - if (port->send_discover) {
> + if (port->send_discover && port->negotiated_rev < PD_REV30) {
> tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
> break;
> }
> @@ -2863,7 +2863,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
> PD_MSG_CTRL_NOT_SUPP,
> NONE_AMS);
> } else {
> - if (port->send_discover) {
> + if (port->send_discover && port->negotiated_rev < PD_REV30) {
> tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
> break;
> }
> @@ -2872,7 +2872,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
> }
> break;
> case PD_CTRL_VCONN_SWAP:
> - if (port->send_discover) {
> + if (port->send_discover && port->negotiated_rev < PD_REV30) {
> tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
> break;
> }