From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
Mario Limonciello <mario.limonciello@amd.com>,
Bjorn Helgaas <bhelgaas@google.com>,
"open list:PCI SUBSYSTEM" <linux-pci@vger.kernel.org>,
"open list:THUNDERBOLT DRIVER" <linux-usb@vger.kernel.org>,
"open list:RADEON and AMDGPU DRM DRIVERS"
<amd-gfx@lists.freedesktop.org>,
"open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>,
"open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS"
<nouveau@lists.freedesktop.org>,
Hans de Goede <hdegoede@redhat.com>,
Michael Jamet <michael.jamet@intel.com>,
Yehezkel Bernat <YehezkelShB@gmail.com>,
Alexander.Deucher@amd.com,
Andreas Noever <andreas.noever@gmail.com>
Subject: Re: [PATCH v3 05/12] PCI: Detect root port of internal USB4 devices by `usb4-host-interface`
Date: Mon, 14 Feb 2022 13:08:26 +0200 [thread overview]
Message-ID: <Ygo1eoVe8D0b80QF@lahna> (raw)
Message-ID: <20220214110826.65IIbZtIx2-trWYGDB34fhZQGzEVhpLRm9YwPNN-A0w@z> (raw)
In-Reply-To: <20220214085202.GA21533@wunner.de>
On Mon, Feb 14, 2022 at 09:52:02AM +0100, Lukas Wunner wrote:
> On Mon, Feb 14, 2022 at 09:34:26AM +0200, Mika Westerberg wrote:
> > On Fri, Feb 11, 2022 at 03:45:46PM -0600, Bjorn Helgaas wrote:
> > > My expectation is that "USB" (like "PCI" and "PCIe") tells me
> > > something about how a device is electrically connected and how
> > > software can operate it. It doesn't really tell me anything about
> > > whether those electrical connections are permanent, made through an
> > > internal slot, or made through an external connector and cable.
> >
> > It is used to identify "tunneled" ports (whether PCIe, USB 3.x or
> > DisplayPort). Tunnels are created by software (in Linux it is the
> > Thunderbolt driver) and are dynamic in nature. The USB4 links go over
> > USB Type-C cable which also is something user can plug/unplug freely.
> >
> > I would say it is reasonable expectation that anything behind these
> > ports can be assumed as "removable".
>
> USB gadgets may be soldered to the mainboard. Those cannot be
> unplugged freely. It is common practice to solder USB Ethernet
> or USB FTDI serial ports and nothing's preventing a vendor to solder
> USB4/Thunderbolt gadgets.
Right, that's why I say it is "reasonable expectation" that anything
behind these ports can be assumed "removable" :) Of course they don't
have to be but if we assume that in the driver where this actually
matters we should be on the safe side, no?
next prev parent reply other threads:[~2022-02-14 11:30 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-11 19:32 [PATCH v3 00/12] Overhaul `is_thunderbolt` Mario Limonciello
2022-02-11 19:32 ` [PATCH v3 01/12] thunderbolt: move definition of PCI_CLASS_SERIAL_USB_USB4 Mario Limonciello
2022-02-11 21:02 ` Bjorn Helgaas
2022-02-11 19:32 ` [PATCH v3 02/12] PCI: Move `is_thunderbolt` check for lack of command completed to a quirk Mario Limonciello
2022-02-11 21:20 ` Bjorn Helgaas
2022-02-11 19:32 ` [PATCH v3 03/12] PCI: Move check for old Apple Thunderbolt controllers into " Mario Limonciello
2022-02-11 21:35 ` Bjorn Helgaas
2022-02-11 22:06 ` Limonciello, Mario
2022-02-14 7:15 ` Mika Westerberg
2022-02-13 9:19 ` Lukas Wunner
2022-02-13 9:21 ` Lukas Wunner
2022-02-14 7:23 ` Mika Westerberg
2022-02-11 19:32 ` [PATCH v3 04/12] PCI: Drop the `is_thunderbolt` attribute from PCI core Mario Limonciello
2022-02-13 8:20 ` Lukas Wunner
2022-02-13 17:26 ` Limonciello, Mario
2022-02-14 7:27 ` Mika Westerberg
2022-02-11 19:32 ` [PATCH v3 05/12] PCI: Detect root port of internal USB4 devices by `usb4-host-interface` Mario Limonciello
2022-02-11 21:45 ` Bjorn Helgaas
2022-02-14 7:34 ` Mika Westerberg
2022-02-14 8:52 ` Lukas Wunner
2022-02-14 10:56 ` Mika Westerberg [this message]
2022-02-14 11:08 ` Mika Westerberg
2022-02-14 11:11 ` Mika Westerberg
2022-02-17 20:40 ` Bjorn Helgaas
2022-02-11 19:32 ` [PATCH v3 06/12] PCI: Explicitly mark USB4 NHI devices as removable Mario Limonciello
2022-02-11 21:58 ` Bjorn Helgaas
2022-02-11 19:32 ` [PATCH v3 07/12] PCI: Set ports for discrete USB4 controllers appropriately Mario Limonciello
2022-02-11 22:10 ` Bjorn Helgaas
2022-02-11 19:32 ` [PATCH v3 08/12] drm/amd: drop the use of `pci_is_thunderbolt_attached` Mario Limonciello
2022-02-11 19:32 ` [PATCH v3 09/12] drm/nouveau: " Mario Limonciello
2022-02-11 19:32 ` [PATCH v3 10/12] drm/radeon: " Mario Limonciello
2022-02-11 19:32 ` [PATCH v3 11/12] platform/x86: amd-gmux: " Mario Limonciello
2022-02-11 19:32 ` [PATCH v3 12/12] PCI: drop `pci_is_thunderbolt_attached` Mario Limonciello
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