HP laserjet m1005 printer

Question

I have never understood how printing works in linux and this adds to my woes while installing printers. I have this HP printer and am using cups 1.6. Once
the printer is plugged in I can see the following with dmesg
[    2.629357] usb 2-1.6: new low-speed USB device number 6 using ehci_hcd
[    3.980041] usblp0: USB Bidirectional printer dev 5 if 1 alt 0 proto 2 vid 0x03F0 pid 0x3B17
[    3.980060] usbcore: registered new interface driver usblp
I assume that this means that the kernel detected that a printer was plugged in and registered an "interface driver" (I do not know what an "interface driver"
is).  Now, cups needs to detect this printer. I do not understand why it does not? I mean, the kernel has already identified it as a printer.
Then, I am confused about what hp-setup does. In the wiki about cups, hp-setup was not mentioned. Nevetheless, when I run hp-setup as root I find that
it detects the connected printer
Using device: hp:/usb/HP_LaserJet_M1005?serial=KJ2SR56
but it has its own issues: all this mess about python2, python3 and python-dbus. May be I will be able to install this printer by reading "n" number of forums
but I want to understand the process of printing right from the point I connect my printer so that I can be satisfied that I have learnt something. Can
somebody please explain what is this process in simple terms ? Please let me know if any other information is needed regarding my printer.

Answer 1

jpvarma wrote:
[ 3.980060] usbcore: registered new interface driver usblp
I assume that this means that the kernel detected that a printer was plugged in and registered an "interface driver" (I do not know what an "interface driver"
is).  Now, cups needs to detect this printer. I do not understand why it does not? I mean, the kernel has already identified it as a printer.
The "interface driver" is usblp, which is the kernel module that creates (I believe) /dev/usb/lp0. I'm not 100% sure about the device location, because I've had issues with CUPS 1.6 and my printer doesn't like the usblp kernel module.
jpvarma wrote:Then, I am confused about what hp-setup does. In the wiki about cups, hp-setup was not mentioned. Nevetheless, when I run hp-setup as root I find that
it detects the connected printer
As 12eason suggested, you probably won't need to do much to get your printer working. Judging by a quick Google search, it doesn't appear that your printer requires the firmware to be uploaded to the device at connect time. That means hp-setup probably won't do much for you beyond setting up the print queue in CUPS if you follow through the entire series of questions. It doesn't work on my printer (HP LaserJet 1020, requires firmware), but it may on yours. Check your /etc/cups/printers.conf for entries after you've run through the entirety of hp-setup.
jpvarma wrote:Can somebody please explain what is this process in simple terms ? Please let me know if any other information is needed regarding my printer.
Truth be told, you might be better off asking this on a CUPS-related mailing list. CUPS is complicated software and the process is further affected by which backends you have available (hplip adds new ones, for instance).
Are you mostly interested in how CUPS works or are you having issues getting it to work with your printer? I suspect the latter, but I'm also curious what you got out of the Arch Wiki on CUPS and what you've tried (you have tried using the web interface to add the printer, haven't you?).
In short: Just because the kernel is reporting a printer attached doesn't mean it knows how to print to it (it doesn't--the kernel isn't responsible for that anymore than it should be responsible for HTTP). That's the job of CUPS. You also have to have CUPS configured with the correct PPDs for your printer since, AFAIK, CUPS essentially treats all printers as PostScript devices; the backends and PPDs simply translate PS to the native protocol of the printer (mine is a Zjstream protocol printer, which requires either hplip or foo2zjs--yours is different). If CUPS isn't configured (read the wiki; also, you may need to futz with /etc/cups/cupsd.conf if you have trouble accessing http://localhost:631), it won't print, regardless of what the kernel is reporting.