Re: [PATCH v4] usb: typec: tcpm: fix create duplicate source-capabilities file

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

On Wed, Feb 15, 2023 at 01:49:51PM +0800, Xu Yang wrote:
> The kernel will dump in the below cases:
> sysfs: cannot create duplicate filename
> '/devices/virtual/usb_power_delivery/pd1/source-capabilities'
> 
> 1. After soft reset has completed, an Explicit Contract negotiation occurs.
> The sink device will receive source capabilitys again. This will cause
> a duplicate source-capabilities file be created.
> 2. Power swap twice on a device that is initailly sink role.
> 
> This will unregister existing capabilities when above cases occurs.
> 
> Fixes: 8203d26905ee ("usb: typec: tcpm: Register USB Power Delivery Capabilities")
> cc: <stable@vger.kernel.org>
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

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

> ---
> changelogs:
> v2: unregister existing capabilities on specific cases
> v3: add changelog and modify commit message
> v4: reset port->partner_source_caps to NULL
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index a0d943d78580..7f39cb9b3429 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4570,6 +4570,9 @@ static void run_state_machine(struct tcpm_port *port)
>  	case SOFT_RESET:
>  		port->message_id = 0;
>  		port->rx_msgid = -1;
> +		/* remove existing capabilities */
> +		usb_power_delivery_unregister_capabilities(port->partner_source_caps);
> +		port->partner_source_caps = NULL;
>  		tcpm_pd_send_control(port, PD_CTRL_ACCEPT);
>  		tcpm_ams_finish(port);
>  		if (port->pwr_role == TYPEC_SOURCE) {
> @@ -4589,6 +4592,9 @@ static void run_state_machine(struct tcpm_port *port)
>  	case SOFT_RESET_SEND:
>  		port->message_id = 0;
>  		port->rx_msgid = -1;
> +		/* remove existing capabilities */
> +		usb_power_delivery_unregister_capabilities(port->partner_source_caps);
> +		port->partner_source_caps = NULL;
>  		if (tcpm_pd_send_control(port, PD_CTRL_SOFT_RESET))
>  			tcpm_set_state_cond(port, hard_reset_state(port), 0);
>  		else
> @@ -4718,6 +4724,9 @@ static void run_state_machine(struct tcpm_port *port)
>  		tcpm_set_state(port, SNK_STARTUP, 0);
>  		break;
>  	case PR_SWAP_SNK_SRC_SINK_OFF:
> +		/* will be source, remove existing capabilities */
> +		usb_power_delivery_unregister_capabilities(port->partner_source_caps);
> +		port->partner_source_caps = NULL;
>  		/*
>  		 * Prevent vbus discharge circuit from turning on during PR_SWAP
>  		 * as this is not a disconnect.
> -- 
> 2.34.1

-- 
heikki