2024-03-12 01:28:48

by Michael Wu

Subject: [PATCH] usb: typec: tcpm: support sink port for debounce

When both CC1 and CC2 pins are simultaneously pulled up, it often leads
to the double Rp to Vbus cable being stuck in the SNK_ATTACH_WAIT state.
And the state machine fails to transition to the SNK_ATTACHED state.

Therefore, it is recommended to focus on transitioning the sink port to
the SNK_DEBOUNCED state instead. By doing so, the desired outcome can be
achieved more effectively.

[ 134.525750] VBUS on
[ 134.713240] CC1: 0 -> 3, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected]
[ 134.713249] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]

Signed-off-by: Michael Wu <[email protected]>
---
drivers/usb/typec/tcpm/tcpm.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 0965972310275..9228dbd78bf2b 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4197,6 +4197,8 @@ static void run_state_machine(struct tcpm_port *port)
else if (tcpm_port_is_disconnected(port))
tcpm_set_state(port, SNK_UNATTACHED,
PD_T_PD_DEBOUNCE);
+ else if (tcpm_port_is_sink(port))
+ tcpm_set_state(port, SNK_DEBOUNCED, 0);
break;
case SNK_DEBOUNCED:
if (tcpm_port_is_disconnected(port))
--
2.29.0

2024-03-12 11:08:15

by Heikki Krogerus

Subject: Re: [PATCH] usb: typec: tcpm: support sink port for debounce

On Tue, Mar 12, 2024 at 09:13:00AM +0800, Michael Wu wrote:
> When both CC1 and CC2 pins are simultaneously pulled up, it often leads
> to the double Rp to Vbus cable being stuck in the SNK_ATTACH_WAIT state.
> And the state machine fails to transition to the SNK_ATTACHED state.
>
> Therefore, it is recommended to focus on transitioning the sink port to
> the SNK_DEBOUNCED state instead. By doing so, the desired outcome can be
> achieved more effectively.

Recommended by whom (or what)?

> [ 134.525750] VBUS on
> [ 134.713240] CC1: 0 -> 3, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected]
> [ 134.713249] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
>
> Signed-off-by: Michael Wu <[email protected]>
> ---
> drivers/usb/typec/tcpm/tcpm.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 0965972310275..9228dbd78bf2b 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4197,6 +4197,8 @@ static void run_state_machine(struct tcpm_port *port)
> else if (tcpm_port_is_disconnected(port))
> tcpm_set_state(port, SNK_UNATTACHED,
> PD_T_PD_DEBOUNCE);
> + else if (tcpm_port_is_sink(port))
> + tcpm_set_state(port, SNK_DEBOUNCED, 0);
> break;
> case SNK_DEBOUNCED:
> if (tcpm_port_is_disconnected(port))
> --
> 2.29.0

--
heikki