pizza at shaftnet.org
Wed Feb 22 16:31:49 PST 2017
On Wed, Feb 22, 2017 at 09:49:41PM +0000, Justin Carlson wrote: > Do you have any sense for whether 'serial-number-is-bogus' is reliably > detectable across manufacturers? Like, people leave it a zero-length > field, or set to all zeros, or similar? No device manufacturer would do > something like set the same non-zero serial number for all devices, would > they? Would They? Unfortunately, it is absolutely unreliably unreliable. I have a printer here made by a major (non-conusumer) manufacturer that has a valid serial number that matches the sticker on the side. I've seen two other examples of this same model that have a serial number of '00000' I've seen them with null strings, all 0s, equal non-null, and seemingly unique but not even remotely matching any labels on the device or packaging. I've also seen them report badness via the USB (or IEEE1284) descriptors but provide a vendor-specific mechanism to query the real serial number. (...so as hairy as the CUPS usb backend is, the one I wrote for various dyesub models supported by Gutenprint is all that, and worse. :) I started down the path you did, using USB topology info when the serial number was unknown.. only to give up as the cure turned out to be worse than the disease... In all seriousness, your best bet will probably be, at startup, to call the usb backend without any arguments, as that'll give you the URIs of all printers that can be detected. ...Anyway... - Solomon -- Solomon Peachy pizza at shaftnet dot org Delray Beach, FL ^^ (email/xmpp) ^^ Quidquid latine dictum sit, altum videtur.