From: "mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com>
To: "Moń, Tomasz" <tomasz.mon@nordicsemi.no>
Cc: "YehezkelShB@gmail.com" <YehezkelShB@gmail.com>,
"andreas.noever@gmail.com" <andreas.noever@gmail.com>,
"michael.jamet@intel.com" <michael.jamet@intel.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: Re: USB 2.0 host controller for Thunderbolt 4
Date: Tue, 23 May 2023 15:54:39 +0300 [thread overview]
Message-ID: <20230523125439.GP45886@black.fi.intel.com> (raw)
In-Reply-To: <551c6ce270bac239fbcebd5280e426851b84ee0e.camel@nordicsemi.no>
On Tue, May 23, 2023 at 09:45:49AM +0000, Moń, Tomasz wrote:
> On Tue, 2023-05-23 at 12:01 +0300, Mika Westerberg wrote:
> > On Tue, May 23, 2023 at 10:53:17AM +0200, Tomasz Moń wrote:
> > > When I connect Thunderbolt 3 dock, two new host controllers show up:
> > > * usb5 - USB 2.0 High-Speed
> > > * usb6 - USB 3.0 SuperSpeed
> > >
> > > Devices connected through Thunderbolt 3 dock end up on expected host
> > > controllers, i.e. Low/Full/High-Speed devices connect to usb5 and
> > > SuperSpeed devices end up on usb6.
> > >
> > > Is Thunderbolt 3 essentially tunnelling the USB 2.0 traffic (by
> > > tunnelling PCIe xHCI host controller traffic) on the superspeed
> > > differential pairs (operating in alternate TBT3 mode)?
> >
> > It is not. The USB 2.x wires are separate on type-C cables.
>
> Yes, the USB 2.x wires are separate on type-C cables. But this does not
> answer the question why there is new USB 2.0 High-Speed controller
> showing up that the devices do connect to.
So for the xHCI on the dock itself, I think this is what you mean, it is
just a normal PCIe endpoint and all that traffic goes over a PCIe
tunnel, including the USB 2.x.
next prev parent reply other threads:[~2023-05-23 12:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-23 8:53 USB 2.0 host controller for Thunderbolt 4 Tomasz Moń
2023-05-23 9:01 ` Mika Westerberg
2023-05-23 9:45 ` Moń, Tomasz
2023-05-23 11:03 ` Mathias Nyman
2023-05-23 12:54 ` mika.westerberg [this message]
2023-05-23 9:44 ` Oliver Neukum
2023-05-23 9:49 ` Tomasz Moń
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