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From: Guenter Roeck <linux@roeck-us.net>
To: cy_huang <u0084500@gmail.com>
Cc: heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	cy_huang@richtek.com
Subject: Re: [PATCH] usb: typec: tcpm: Fix if vbus before cc, hard_reset_count not reset issue
Date: Wed, 2 Sep 2020 09:57:13 -0700	[thread overview]
Message-ID: <20200902165713.GG56237@roeck-us.net> (raw)
In-Reply-To: <1599060933-8092-1-git-send-email-u0084500@gmail.com>

On Wed, Sep 02, 2020 at 11:35:33PM +0800, cy_huang wrote:
> From: ChiYuan Huang <cy_huang@richtek.com>
> 
> Fix: If vbus event is before cc_event trigger, hard_reset_count
> won't bt reset for some case.
> 
> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
> ---
> Below's the flow.
> 
> _tcpm_pd_vbus_off() -> run_state_machine to change state to SNK_UNATTACHED
> call tcpm_snk_detach() -> tcpm_snk_detach() -> tcpm_detach()
> tcpm_port_is_disconnected() will be called.
> But port->attached is still true and port->cc1=open and port->cc2=open
> 
> It cause tcpm_port_is_disconnected return false, then hard_reset_count won't be reset.
> After that, tcpm_reset_port() is called.
> port->attached become false.
> 
> After that, cc now trigger cc_change event, the hard_reset_count will be kept.
> Even tcpm_detach will be called, due to port->attached is false, tcpm_detach()
> will directly return.
> 
> CC_EVENT will only trigger drp toggling again.
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index a48e3f90..5c73e1d 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -2797,8 +2797,7 @@ static void tcpm_detach(struct tcpm_port *port)
>  		port->tcpc->set_bist_data(port->tcpc, false);
>  	}
>  
> -	if (tcpm_port_is_disconnected(port))
> -		port->hard_reset_count = 0;
> +	port->hard_reset_count = 0;
>  

Doesn't that mean that the state machine will never enter
error recovery ?

Guenter

>  	tcpm_reset_port(port);
>  }
> -- 
> 2.7.4
> 

  reply	other threads:[~2020-09-02 16:57 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-02 15:35 [PATCH] usb: typec: tcpm: Fix if vbus before cc, hard_reset_count not reset issue cy_huang
2020-09-02 16:57 ` Guenter Roeck [this message]
2020-09-03 16:21   ` ChiYuan Huang
2020-09-04 19:41     ` Guenter Roeck
2020-09-05  1:24       ` ChiYuan Huang
2020-09-05 15:51         ` Guenter Roeck
2020-09-06 15:22           ` ChiYuan Huang
2020-09-15  3:07             ` ChiYuan Huang
2020-10-02 13:31               ` Greg KH
2020-10-02 14:26                 ` Guenter Roeck
2020-10-05 11:08                   ` Greg KH
2020-10-05 15:30                     ` Guenter Roeck
2020-10-06  4:37                       ` ChiYuan Huang
2020-10-06 16:52                         ` Jun Li
2020-10-06 17:39                           ` ChiYuan Huang
2020-10-07 10:13                             ` ChiYuan Huang
2020-10-09  6:12                               ` Jun Li
2020-10-09 16:06                                 ` ChiYuan Huang
2020-10-10 11:21                                   ` Jun Li
2020-10-10 19:31                                     ` Guenter Roeck
2020-10-12  6:22                                       ` ChiYuan Huang
2020-10-12  9:25                                         ` Jun Li
2020-10-12  8:58                                       ` Jun Li
2020-10-10 15:46                                   ` Guenter Roeck
2020-10-09  2:58                             ` Jun Li

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