Re: Duplex Printer Problem

["George N. White III" <gnwiii@xxxxxxxxx>]

On Wed, Sep 7, 2022 at 10:38 AM Jonathan Ryshpan <jonrysh@xxxxxxxxxxx> wrote:

On Wed, 2022-09-07 at 08:32 -0300, George N. White III wrote:

On Tue, Sep 6, 2022 at 11:46 PM Jonathan Ryshpan <jonrysh@xxxxxxxxxxx> wrote:

For USB, see https://github.com/OpenPrinting/ipp-usb.  The "Issues" section has

examples of troubleshooting on linux:

So there are, but none of them seems to have much to do with my situation.

The problems/printer models aren't the same, but some of the troubleshooting methods

could help pin down the problem.  One reason troubleshooting IPP-USB is hard (quoting the README):

Unfortunately, the naive implementation, which simply relays a TCP connection to USB, does not work. It happens because closing the TCP connection on the client side has a useful side effect of discarding all data sent to this connection from the server side, but it does not happen with USB connections. In the case of USB, all data not received by the client will remain in the USB buffers, and the next time the client connects to the device, it will receive unexpected data, left from the previous abnormally completed request.

Actually, it is an obvious flaw in the IPP-over-USB standard, but we have to live with it.

The easy workaround would be to switch to a network connection.   Opening an issue on the ipp-usb

github site takes effort, but could be a useful contribution to the community.

This implies that cups needs to communicate with the printer to find out something (say whether the 

printer has duplex capability), but can't because of communication issues which would be solved if 

IPP-USB were working properly.

In addition to getting printer capabilities, CUPS needs to send setup data  (e.g., non-duplex request) to

the printer followed by the print data.   The problem for troubleshooting with USB is that some cleanup is

needed after a failed job/test.

A test would be to change the connection to the printer from USB to TCP/IP, i.e. I should disconnect USB, 

attach Ethernet on the printer, set up the printer for Ethernet and see what happens. Is all this correct?

TCP/IP is used on ethernet cables and WiFi. Ethernet generally requires a router with DHCP.  Typical

home internet these days provides a combined modem/router with both wifi and ethernet, so if you

are using wfi you might have to move the printer close enough to the router to connect ethernet.

Wireless is also supported by your printer.  Apple Airprint was invented to allow iPhone and iPad

users to print directly to a printer, This makes my partner (and the stores that provide printer supplies!)

very happy.   Use whatever your network provides.

 

I suspect that ipp-usb is not going to help because the HP m255dw printer doesn't seem to be supported:

# ipp-usb check
Configuration files: OK
No IPP over USB devices found

It is possible that HP has some special sauce for USB printing, but to be certain you probably

need the help of the ipp-usb exports via their github Issues.

--

George N. White III

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