On Mon 16 Aug 2021 at 19:55:49 +0100, Brian wrote: > On Mon 16 Aug 2021 at 19:51:50 +0200, Nicolas George wrote: > > > Brian (12021-08-02): > > > My thinking is that a USB printer uses libusb, just as a scanner does. > > > No kernel driver involved. The printer drivers are "internal" to CUPS. > > > > The output of `/sbin/modinfo usblp` confirms there is a kernel driver > > for USB printers. > > > > filename: > > /lib/modules/5.10.0-8-amd64/kernel/drivers/usb/class/usblp.ko > > license: GPL > > description: USB Printer Device Class driver > > author: Michael Gee, Pavel Machek, Vojtech Pavlik, Randy Dunlap, > > Pete Zaitcev, David Paschal > > The existence of the usblp kernel module is not in doubt. > > > It is entirely possible that both this and generic libusb access are > > supported. > > The printing system detaches usblp when it is met.
>From /cups/cups-2.3.0/backend/usb-libusb.c: /* * Get the "usblp" kernel module out of the way. This backend only * works without the module attached. */ -- Brian.
