Created attachment 185117 [details] My printers installation SUMMARY I learned that my printer can be installed as driverless. I deleted the instance that uses a driver and created a driverless instance. Although I know that this printer supports duplex printing none of KDE apps I have tried will allow me to choose duplex. STEPS TO REPRODUCE 1. Install printer with the driverless option 2. Choose a KDE app and an appropriatte file 3. Open the app's print option 4. Expand the the printers options and look for double sided printing 5. Try to click on one of the double sided options OBSERVED RESULT The double sided options are grey and cannot be selected. EXPECTED RESULT I should be able to choose one of the double sided options. SOFTWARE/OS VERSIONS Operating System: Fedora Linux 42 KDE Plasma Version: 6.4.4 KDE Frameworks Version: 6.17.0 Qt Version: 6.9.2 Kernel Version: 6.16.7-200.fc42.x86_64 (64-bit) Graphics Platform: Wayland Processors: 8 × Intel® Core™ i7-6700 CPU @ 3.40GHz Memory: 32 GiB of RAM (31.2 GiB usable) Graphics Processor: Intel® HD Graphics 530 Manufacturer: LENOVO Product Name: 10MLS0A400 System Version: ThinkCentre M910s ADDITIONAL INFORMATION If I use a non-kde app such as Libre writer the duplex option is available. The printer using the driverless installation is actually able to print double sided. "lp -d HP_LaserJet_MFP_M232-M237 -o sides=two-sided-long-edge my-file" confirms that double sided printing works. For further testing added the driver option back on an extra instance of the printer. I confirmed that the duplex option is available when using the driver instance.
If another app prints double-sided just fine with the driverless option, then this sounds like an app problem, not print manager. If the app is using the standard Qt print dialog apis and it's all apps using this capability, then it's possible that it could be a Qt print dialog problem. I checked with Kate and double-side with the IPP everywhere (driverless) is available and working with a test printer I have (HP Envy). Which apps have you tried with? Either way, this should probably be closed and re-classified.
I checked Chrome and Firefox. Both dialogs show that double sided is available when using the driverless printer. Wireshark seems to use the native dialog and duplex is not available for the driverless instance.