From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Badhri Jagan Sridharan <badhri@google.com>
Cc: Oliver Neukum <oneukum@suse.com>,
Guenter Roeck <linux@roeck-us.net>,
Mats Karrman <mats.dev.list@gmail.com>,
Greg KH <gregkh@linuxfoundation.org>,
Felipe Balbi <felipe.balbi@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
USB <linux-usb@vger.kernel.org>
Subject: Re: [PATCH v17 2/3] usb: USB Type-C connector class
Date: Thu, 20 Apr 2017 14:55:29 +0300 [thread overview]
Message-ID: <20170420115529.GA4769@kuha.fi.intel.com> (raw)
In-Reply-To: <CAPTae5+C5xVqEbq2v+J+OWh8srsbS-fM612Sbu5Cq6MSgmRr7g@mail.gmail.com>
Hi,
On Wed, Apr 19, 2017 at 07:45:00AM -0700, Badhri Jagan Sridharan wrote:
> >> What is the expected behavior when the userspace changes the
> >> preferred_role node when the port is in connected state ?
> >>
> >> 1. the state machine re-resolves the port roles right away based on
> >> the new state machine in place ? (or)
> >
> > No! There are separate attributes for sending role swap requests.
>
> Right. But, that might not be helpful in cases when PD is not implemented.
> and Implementing PD is not mandatory according the spec :/
>
> FYI quoting from the Type-C specification release(page 24),
> role swaps are not limited to devices that only support PD.
>
> "Two independent set of mechanisms are defined to allow a USB Type-C
> DRP to functionally swap power and data roles. When USB PD is
> supported, power and data role swapping is performed as a subsequent
> step following the initial connection process. For non-PD implementations,
> power/data role swapping can optionally be dealt with as part of the initial
> connection process."
>
> But, the current interface definition actually prevents current/data role
> swaps for non-pd devices.
No it doesn't. When USB PD is not supported, you can still use
data_role to swap the role. Of course, the lower level driver may
not support any role swapping in that case.
Thanks,
--
heikki
next prev parent reply other threads:[~2017-04-20 11:55 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-21 14:24 [PATCH v17 0/3] USB Type-C Connector class Heikki Krogerus
2017-02-21 14:24 ` [PATCH v17 1/3] lib/string: add sysfs_match_string helper Heikki Krogerus
2017-02-21 14:24 ` [PATCH v17 2/3] usb: USB Type-C connector class Heikki Krogerus
2017-03-02 15:22 ` Mats Karrman
2017-03-03 3:13 ` Guenter Roeck
2017-03-03 7:29 ` Mats Karrman
2017-03-03 9:48 ` Enric Balletbo Serra
2017-03-03 12:59 ` Heikki Krogerus
2017-03-03 14:49 ` Guenter Roeck
2017-03-03 19:27 ` Mats Karrman
2017-03-06 9:37 ` Oliver Neukum
2017-03-06 13:14 ` Heikki Krogerus
2017-03-07 22:30 ` Mats Karrman
2017-03-08 1:38 ` Guenter Roeck
2017-04-08 23:09 ` USB Type-C Port Manager API concern Mats Karrman
2017-04-09 15:16 ` Guenter Roeck
2017-04-09 21:05 ` Mats Karrman
2017-04-14 2:57 ` Guenter Roeck
2017-04-14 8:30 ` Mats Karrman
2017-03-08 13:58 ` [PATCH v17 2/3] usb: USB Type-C connector class Heikki Krogerus
2017-03-10 22:22 ` Mats Karrman
2017-03-10 23:41 ` Guenter Roeck
2017-04-18 18:52 ` Badhri Jagan Sridharan
2017-04-19 11:23 ` Heikki Krogerus
2017-04-19 14:45 ` Badhri Jagan Sridharan
2017-04-19 15:14 ` Guenter Roeck
2017-04-19 17:22 ` Badhri Jagan Sridharan
2017-04-19 19:29 ` Guenter Roeck
2017-04-20 12:24 ` Heikki Krogerus
2017-04-20 19:46 ` Badhri Jagan Sridharan
2017-04-21 12:12 ` Heikki Krogerus
2017-04-21 13:14 ` Guenter Roeck
2017-04-21 14:27 ` Rajaram R
2017-04-21 16:43 ` Guenter Roeck
2017-04-22 9:23 ` Rajaram R
2017-04-24 17:50 ` Badhri Jagan Sridharan
2017-04-25 8:26 ` Rajaram R
2017-04-25 14:10 ` Guenter Roeck
2017-04-27 6:20 ` Rajaram R
2017-04-27 18:10 ` Guenter Roeck
2017-04-28 10:52 ` Heikki Krogerus
2017-04-20 11:55 ` Heikki Krogerus [this message]
2017-03-03 14:41 ` Guenter Roeck
2017-03-03 3:35 ` Peter Chen
2017-03-03 4:29 ` Guenter Roeck
2017-03-03 4:52 ` Peter Chen
2017-03-03 14:36 ` Guenter Roeck
2017-03-06 1:24 ` Peter Chen
2017-03-03 14:31 ` Heikki Krogerus
2017-03-06 1:15 ` Peter Chen
2017-03-06 13:16 ` Heikki Krogerus
2017-03-07 1:36 ` Peter Chen
2017-03-07 8:57 ` Heikki Krogerus
2017-03-08 1:53 ` Guenter Roeck
2017-03-08 6:50 ` Peter Chen
2017-03-08 14:44 ` Guenter Roeck
2017-03-09 2:00 ` Peter Chen
2017-02-21 14:24 ` [PATCH v17 3/3] usb: typec: add driver for Intel Whiskey Cove PMIC USB Type-C PHY Heikki Krogerus
2017-02-21 15:42 ` [PATCH v17 0/3] USB Type-C Connector class Felipe Balbi
2017-03-21 11:14 ` Heikki Krogerus
2017-03-21 10:23 ` Greg KH
2017-03-21 10:37 ` Heikki Krogerus
2017-03-22 21:15 ` Mats Karrman
2017-03-23 8:16 ` Heikki Krogerus
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