On Mon, 18 Mar 2019, Felipe Balbi wrote: > > The spec says: > > > > All Debug Devices, with the exception of fixed address devices, > > must implement all required standard commands in the core > > device framework. > > > > But that refers to standard _commands_, not standard _descriptors_. > > GetDescriptor() is a standard command, though. I would say that we're > either missing proper Interface and Configuration descriptors, or > usbcore used to have some special cases for ehci debug port which got > "fixed" out of existence over time. There is drivers/usb/early/ehci-dbgp.c. That driver bypasses usbcore entirely. Alan Stern > > The spec also says that a debug device cannot be enumerated by standard > > USB-2 means, because it supports an ep0 maxpacket size of only 8 rather > > than 64. > > > > And yes, the driver is EHCI-specific -- it says so right at the start > > of the file. On the other hand, I don't see any reason in theory why > > it couldn't work with any other host controller that has USB high-speed > > debug support. > > Thanks for confirming.
