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Date:   Mon, 8 Apr 2019 13:34:36 +0300
From:   Mika Westerberg <mika.westerberg@linux.intel.com>
To:     Lukas Wunner <lukas@wunner.de>
Cc:     linux-kernel@vger.kernel.org,
        Michael Jamet <michael.jamet@intel.com>,
        Yehezkel Bernat <YehezkelShB@gmail.com>,
        Andreas Noever <andreas.noever@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Christian Kellner <ckellner@redhat.com>,
        Mario.Limonciello@dell.com
Subject: Re: [PATCH v3 19/36] thunderbolt: Extend tunnel creation to more
 than 2 adjacent switches
Message-ID: <20190408103436.GO3622@lahna.fi.intel.com>
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 <20190408073517.GA3622@lahna.fi.intel.com>
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On Mon, Apr 08, 2019 at 11:49:04AM +0200, Lukas Wunner wrote:
> On Mon, Apr 08, 2019 at 12:07:44PM +0300, Mika Westerberg wrote:
> > On Mon, Apr 08, 2019 at 10:53:37AM +0200, Lukas Wunner wrote:
> > > Hm, what other cases are there, i.e. what is the meaning of a tb_regs_hop's
> > > "next_hop" field if "out_port" doesn't have a remote?  (And why does it
> > > need to be tracked on the out_port?  In case a remote is added later?)
> > 
> > We also need to program HopIDs for adapter ports (PCIe, DP, NHI) in
> > order to enable a path. The "next_hop" from NULL port to an adapter port
> > tells the HopID a packet gets when it is routed to the adapter port and
> > the adapter port registers then are used to specify which HopID means
> > what (for PCIe there is only 8 but for DP there is 8 and 9, for NHI it
> > can be anything the service driver has negotiated).
> 
> Okay, so in_hopids are the entries allocated in this port's hop config
> space, whereas out_hopids only really bears significance for adapter
> ports.  For null ports (in-between two adapter ports on a path),
> out_hopids is identical to the in_hopids of the next hop (IIUC).
> 
> That probably merits mentioning in struct tb_port's kerneldoc.

Sure, will do.