USB curosity

[Geoffrey Leach]

On 12/13/2015 10:40:10 PM, Berend De Schouwer wrote:
> On Sun, 2015-12-13 at 19:23 -0800, Geoffrey Leach wrote:
> > I have a LaserJet 1300 printer that connects via a Belkin parallel
> > port-to-USB connector. When I send a document to the printer, half
> > the time it prints without hesitation; other times it stalls until I
> > disconnect and re-connect the USB cable. When I do that, here's what
> > dmesg reports:
> 
> I've had some devices do that when they didn't get enough power over
> USB.  Have you tried another USB port?  Do you have a powered USB hub?
> 
> > [80924.737154] usb 4-1.1: USB disconnect, device number 4
> > [80924.737587] usblp0: removed
> > [80926.381095] usb 4-1.1: new full-speed USB device number 5 using
> > ehci-pci
> > [80926.472738] usb 4-1.1: New USB device found, idVendor=050d,
> > idProduct=0002
> > [80926.472749] usb 4-1.1: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=0
> 
> The serial number shouldn't be zero.  Cups uses different serial
> numbers do differentiate between printers.  It shouldn't be, but it
> can
> be.
> 
> What's the cups device?  Are you using parallel://dev/lp0 or usb:// ?
>  Might be something like
> "usb://EPSON/Stylus%20Photo%20R200?serial=M02P20502230111234"
> 
> > [80926.472755] usb 4-1.1: Product: IEEE-1284 Controller
> > [80926.472759] usb 4-1.1: Manufacturer: Belk USB Printing Support
> > [80926.497804] usblp 4-1.1:1.0: usblp0: USB Bidirectional printer
> dev
> > 5 if 0 alt 1 proto 2 vid 0x050D pid 0x0002
> > 
> > CUPS discovers the printer without any problems. However, when I
> send
> > the test document from CUPS, no amount of fiddling with the USB
> cable
> > will cause it to print.
> 
> Will "echo -en 'hello world\n\f' > /dev/usb/lp0" print?  This should
> print the text, with a form feed.  I assume it will block (wait
> forever)

Submitted by root, the command prints fine. dev/usb/lp0 is character special (180/0)

> The device might be /dev/usblp0 or /dev/usb/lp0.  There might be a
> symbolic link /dev/lp0 -> /dev/usb/lp0.