Message-ID: <1479286065.2000.1.camel@suse.com>
Subject: Re: [PATHCv10 1/2] usb: USB Type-C connector class
From: Oliver Neukum <oneukum@suse.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Bin Gao <bin.gao@linux.intel.com>,
        Felipe Balbi <felipe.balbi@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Date: Wed, 16 Nov 2016 09:47:45 +0100
In-Reply-To: <97125354-6634-9d2b-983b-83f73faf1078@roeck-us.net>
References: <20160919111657.22127-1-heikki.krogerus@linux.intel.com>
         <20160919111657.22127-2-heikki.krogerus@linux.intel.com>
         <20161114095148.GA10306@kroah.com>
         <20161114123235.GD22706@kuha.fi.intel.com>
         <97125354-6634-9d2b-983b-83f73faf1078@roeck-us.net>
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On Mon, 2016-11-14 at 06:34 -0800, Guenter Roeck wrote:
> >>> +int typec_connect(struct typec_port *port, struct
> typec_connection *con)
> >>> +{
> >>> +   int ret;
> >>> +
> >>> +   if (!con->partner && !con->cable)
> >>> +           return -EINVAL;
> >>> +
> >>> +   port->connected = 1;
> >>> +   port->data_role = con->data_role;
> >>> +   port->pwr_role = con->pwr_role;
> >>> +   port->vconn_role = con->vconn_role;
> >>> +   port->pwr_opmode = con->pwr_opmode;
> >>> +
> >>> +   kobject_uevent(&port->dev.kobj, KOBJ_CHANGE);
> >>
> >> This worries me.  Who is listening for it?  What will you do with
> it?
> >> Shouldn't you just poll on an attribute file instead?
> >
> > Oliver! Did you need this or can we remove it?
> >
> 
> I'll also have to make sure that the Android folks don't use it.

How then do we notify user space? poll()? Yet another demon.

I do not specifically need this, but I note that uevents are the
general tool we use to notify user space of that kind of events.

	Regards
		Oliver