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Date:   Wed, 2 Oct 2019 10:39:54 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Mika Westerberg <mika.westerberg@linux.intel.com>
Cc:     Oliver Neukum <oneukum@suse.com>,
        Anthony Wong <anthony.wong@canonical.com>,
        Mario.Limonciello@dell.com,
        Andreas Noever <andreas.noever@gmail.com>,
        Yehezkel Bernat <YehezkelShB@gmail.com>,
        Michael Jamet <michael.jamet@intel.com>,
        Rajmohan Mani <rajmohan.mani@intel.com>,
        Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>,
        Alan Stern <stern@rowland.harvard.edu>,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        Lukas Wunner <lukas@wunner.de>
Subject: Re: [RFC PATCH 17/22] thunderbolt: Add initial support for USB4
Message-ID: <20191002083954.GD1687317@kroah.com>
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On Wed, Oct 02, 2019 at 11:30:34AM +0300, Mika Westerberg wrote:
> On Tue, Oct 01, 2019 at 06:27:42PM +0200, Oliver Neukum wrote:
> > Am Dienstag, den 01.10.2019, 18:07 +0300 schrieb Mika Westerberg:
> > 
> > Hi,
> > 
> > > OK, but does that break existing .configs? I mean if you have already
> > > CONFIG_THUNDERBOLT in your .config/defconfig does it now just get
> > > dropped silently?
> > 
> > People will have to look at this new stuff anyway.
> > 
> > > For example firewire has CONFIG_FIREWIRE even though the "standard" name
> > > is IEEE 1394. I was thinking maybe we can do the same for
> > > USB4/Thunderbolt
> > 
> > USB and Thunderbolt used to be distinct protocols. Whereas Firewire
> > was just a colloquial name for IEEE1394. Please be wordy here.
> > "Unified support for USB4 and Thunderbolt4"
> 
> OK.
> 
> I've been thinking this bit more and since Thunderbolt will stick around
> as well (it basically implements all the optional USB4 features and
> more) so would it make sense to have the Kconfig option be
> CONFIG_THUNDERBOLT_USB4 (or CONFIG_USB4_THUNDERBOLT)? That should cover
> both.

I would stick with CONFIG_USB4 but put both in the Kconfig text.  Again,
it will be easier to handle this over time.

> Comments?
> 
> Also does anyone have any thoughts about keeping the driver under
> drivers/thunderbolt vs. moving it under usb like
> drivers/usb/thunderbolt? I'm thinking if anyone not familiar with this
> tries to enable support for USB4 so the first place he/she probably
> looks is under "USB support" menuconfig entry.

You are not sharing/needing any of the drivers/usb/ code just yet,
right?  I imagine that will happen "soon" and when it does, then sure,
moving stuff is fine with me.

thanks,

greg k-h