linux-kernel - Re: [PATCH v3] usb: typec: clear usb_pd flag if change to typec only mode

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Date:   Thu, 9 Dec 2021 12:11:18 +0200
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Steven Syu <stevensyu7@...il.com>
Cc:     gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] usb: typec: clear usb_pd flag if change to typec only
 mode

Hi,

On Wed, Dec 08, 2021 at 03:18:25PM +0800, Steven Syu wrote:
> From: Steven Syu <stevensyu7@...il.com>
> 
> Set usb_pd to 0 when power operation mode
> leaving power delivery. That can avoid user-sepace
> read "yes" form the supports_usb_power_delivery_show() attribute
> but power operation mode already change form power delivery to
> others mode.

I think you need to add a short explanation about the situation where
this can happen - where we loose the USB PD contract.

> Signed-off-by: Steven Syu <stevensyu7@...il.com>
> ---
> changes for v3:
> resubmit and add the changes comment of v1->v2
> 
> v1->v2:
> 1.remove sysfs_notify(&partner_dev->kobj, NULL, "supports_usb_power_delivery"); when operation mode is not PD.
> 2.resubmitted patch by private email for remove footbar in the mail.
> 
>  drivers/usb/typec/class.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index aeef453..2043e07 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -1718,6 +1718,8 @@ void typec_set_pwr_opmode(struct typec_port *port,
>  			partner->usb_pd = 1;
>  			sysfs_notify(&partner_dev->kobj, NULL,
>  				     "supports_usb_power_delivery");
> +		} else if (opmode != TYPEC_PWR_MODE_PD && partner->usb_pd) {
> +			partner->usb_pd = 0;
>  		}
>  		put_device(partner_dev);
>  	}
> -- 
> 2.7.4

thanks,

-- 
heikki