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?
