Maybe this is helpful(?) I had the same troubles after upgrade to bullseye (scanning and printing) using an HP officejet 4630.
After sveral purge and reinstall of hplip I finally moved to sane-airscan and the bug is still unsolved. i hplip is not installed anymore, so maybe it is not hplip related? This is what I do (using sane-airscan): Switching on officejet, /var/log/messages recognizes the new usb device and things look ok. Starting simple scan, two devices are detected: Selecting the eSCL entry (the other entry does not work, but that is another topic). Starting scan gives an error message in a pop-up: "Scanning failed - scan process could not be started" (my translation of the original German message) But the scanner is actually starting to scan without giving a result. /var/log/messages gives: > .... xdg-desktop-por[5256]: Backend call failed: > GDBus.Error:org.freedesktop.DBus.Error.AccessDenied: Operation not permitted > .... xdg-desktop-por[5239]: Failed to get application states: > GDBus.Error:org.freedesktop.portal.Error.Failed: Could not get window list > .... odin kernel: [ 9613.142032] perf: interrupt took too long (2507 > 2500), > lowering kernel.perf_event_max_sample_rate to 79750 > .... odin xdg-desktop-por[5256]: Backend call failed: > GDBus.Error:org.freedesktop.DBus.Error.AccessDenied: Operation not permitted The weird thing now is that without changing anything, just restarting simple-scan scanning works perfectly. Next scan fails again.... In approx. 90% of the scans it fails, in 10% it is ok without changing anything in the setting. Scanimage the same effect: scanimage -v --format=jpeg -o out.jpg scanimage: sane_start: Error during device I/O A few seconds later without changing anything: scanimage -v --format=jpeg -o out.jpg scanimage: scanning image of size 2550x3508 pixels at 24 bits/pixel scanimage: acquiring RGB frame scanimage: min/max graylevel value = 2/255 scanimage: read 26836200 bytes in total Let me know if I can provide better log outputs. Ulrich
