Re: [RFC PATCH 17/22] thunderbolt: Add initial support for USB4

From: Mika Westerberg
Date: Wed Oct 02 2019 - 04:30:41 EST


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.

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.