I'm intending to change the cups page in the book, to remove the Note which says:
| There is a conflict between the Cups libusb backend and the usblp | kernel driver. If you want to use Cups with libusb, do not enable | USB Printer support in your kernel. But since most people don't read blfs-dev, I'm asking here first - in case there are any different opinions. Sorry for the length of thii I (occasionally) use an Epson Stylus Photo R360. Until October I had _always_ used the kernel usblp driver - as a module - instead of libusb. I can vaguely remember that Greg KH reported an "unable to print" problem on lkml several years ago, and that the usblp driver appeared to have come into conflict with libusb (presumably, libusb had changed). I guess that is what eventually triggered the Note. In October, I was building _everything_ to test make-4.0. On my second such build (all the things I couldn't conveniently fit into the main build), I tried adding libusb (strictly, it is now called libusbx and produces libusb-1.0.pc, libusb.pc comes from libusb-compat) and dropping the kernel usblp printer. I was pleased that printing still worked, because this will allow me to reinstate colord - libusb is. or at least was, a recommended dependency - and will let me install usbutils (lsusb might be useful for debugging kernel problems). But earlier this month I wanted to check my ink levels whilst I happened to be using that system. To do that I use escputil from gutenprint, but it needs /dev/usb/lpX (i.e. you can only run it on the machine the printer is connected to) and that device is provided for the kernel usb printer driver. If CONFIG_USB_PRINTER is turned off, /dev/usb/lpX will not be created by whichever flavour of udev is being used. So, a build "by the book" does not let me check my ink levels. :-( So, first I tried what had been recommended in the past in other distros - build usblp as a module, and perhaps try to modprobe it to check the ink levels, and then rmmod it before printing. I built it as a module with 3.13.0: it gets installed as soon as I connect the printer, ink levels are reported, and I am able to print _without_ removing the module. Testing with usblp built-in has taken a little longer (only this one system has libusbx, no newer released kernels to test), but tonight I've built it into 3.12.9 and confirmed that both escputil and printing still work. I assume that changes in libusb, perhaps as part of the move to libusbx, solved the original problem. But printing on BLFS has always given problems for some people - often because different printers are just _different_ - so before I drop the note from the book I'll give everyone a chance to express any concerns. Additional notes: 1. Escputil probably only works on non-multifunction Epson stylus printers. 2. I don't have any printers of other brands on which to test this. ĸen -- das eine Mal als Tragödie, dieses Mal als Farce -- http://linuxfromscratch.org/mailman/listinfo/blfs-support FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page
