Re: [PATCH] Revert "usb: typec: tcpm: clear pd_event queue in PORT_RESET"

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Fri, Aug 09, 2024 at 07:29:01PM +0800, Xu Yang wrote:
> This reverts commit bf20c69cf3cf9c6445c4925dd9a8a6ca1b78bfdf.
> 
> During tcpm_init() stage, if the VBUS is still present after
> tcpm_reset_port(), then we assume that VBUS will off and goto safe0v
> after a specific discharge time. Following a TCPM_VBUS_EVENT event if
> VBUS reach to off state. TCPM_VBUS_EVENT event may be set during
> PORT_RESET handling stage. If pd_events reset to 0 after TCPM_VBUS_EVENT
> set, we will lost this VBUS event. Then the port state machine may stuck
> at one state.
> 
> Before:
> 
> [    2.570172] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [rev1 NONE_AMS]
> [    2.570179] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms]
> [    2.570182] pending state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED @ 920 ms [rev1 NONE_AMS]
> [    3.490213] state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED [delayed 920 ms]
> [    3.490220] Start toggling
> [    3.546050] CC1: 0 -> 0, CC2: 0 -> 2 [state TOGGLING, polarity 0, connected]
> [    3.546057] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
> 
> After revert this patch, we can see VBUS off event and the port will goto
> expected state.
> 
> [    2.441992] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [rev1 NONE_AMS]
> [    2.441999] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms]
> [    2.442002] pending state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED @ 920 ms [rev1 NONE_AMS]
> [    2.442122] VBUS off
> [    2.442125] state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED [rev1 NONE_AMS]
> [    2.442127] VBUS VSAFE0V
> [    2.442351] CC1: 0 -> 0, CC2: 0 -> 0 [state SNK_UNATTACHED, polarity 0, disconnected]
> [    2.442357] Start toggling
> [    2.491850] CC1: 0 -> 0, CC2: 0 -> 2 [state TOGGLING, polarity 0, connected]
> [    2.491858] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
> [    2.491863] pending state change SRC_ATTACH_WAIT -> SNK_TRY @ 200 ms [rev1 NONE_AMS]
> [    2.691905] state change SRC_ATTACH_WAIT -> SNK_TRY [delayed 200 ms]
> 
> Fixes: bf20c69cf3cf ("usb: typec: tcpm: clear pd_event queue in PORT_RESET")
> Cc: stable@vger.kernel.org
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/usb/typec/tcpm/tcpm.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index cce39818e99a..4b02d6474259 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -5655,7 +5655,6 @@ static void run_state_machine(struct tcpm_port *port)
>  		break;
>  	case PORT_RESET:
>  		tcpm_reset_port(port);
> -		port->pd_events = 0;
>  		if (port->self_powered)
>  			tcpm_set_cc(port, TYPEC_CC_OPEN);
>  		else
> -- 
> 2.34.1

-- 
heikki