simple-scan fails to connect to scanner while ippusbxd or ipp-usb are running

[Thomas van der Berg]

I just upgraded from 18.04, where this wasn't a problem. On 20.04, whenever I try to scan a document with simple-scan while ippusbxd or ipp-usb are running (I tried with both) it will fail to connect to the printer and show the following message in a popup: "Failed to scan: Unable to connect to scanner".

I'm not sure what causes this, but whenever I kill ippusbxd (sudo killall -9 ippusbxd) scanning works again. That breaks printing for me though, so now I have to do this awkward dance of killing and restarting ippusbxd to scan or print. I've found quite a bit of people having comparable problems with printers on Ubuntu 20.04 (see https://askubuntu.com/questions/1233521/printer-problems-after-installing-ubuntu-20-04 and https://askubuntu.com/questions/1258462/ubuntu-20-04-simple-scan-does-not-detect-scanner ) but this is the only workardoung for scanning that worked for me.

Some people online recommended replacing ippusbxd with ipp-usb from https://download.opensuse.org/repositories/home:/pzz/xUbuntu_20.04/amd64/ but ipp-usb caused the same problem for me.

My printer is a HP DeskJet 2630

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: simple-scan 3.36.3-0ubuntu0.20.04.0
ProcVersionSignature: Ubuntu 5.4.0-91.102-generic 5.4.151
Uname: Linux 5.4.0-91-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.21
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: XFCE
Date: Sun Dec 5 21:34:09 2021
EcryptfsInUse: Yes
InstallationDate: Installed on 2017-10-09 (1518 days ago)
InstallationMedia: Xubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
MachineType: Dell Inc. XPS 15 9560
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-91-generic root=UUID=81684bb6-dd57-423d-ad09-8d26ed3e4a06 ro nouveau.modeset=0 quiet splash pci=nommconf vt.handoff=7
SourcePackage: simple-scan
UpgradeStatus: Upgraded to focal on 2021-11-14 (21 days ago)
dmi.bios.date: 08/23/2017
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.4.0
dmi.board.name: 05FFDN
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.4.0:bd08/23/2017:svnDellInc.:pnXPS159560:pvr:rvnDellInc.:rn05FFDN:rvrA00:cvnDellInc.:ct10:cvr:
dmi.product.family: XPS
dmi.product.name: XPS 15 9560
dmi.product.sku: 07BE
dmi.sys.vendor: Dell Inc.

[Thomas van der Berg (thomas-van-der-berg-gm)]

Output of `simple-scan -d` from startup to getting the error:

[+0,00s] DEBUG: simple-scan.vala:1720: Starting simple-scan 3.36.3, PID=18139
[+0,00s] DEBUG: unsetenv() is not thread-safe and should not be used after threads are created
[+0,03s] DEBUG: _g_io_module_get_default: Found default implementation gvfs (GDaemonVfs) for ‘gio-vfs’
[+0,11s] DEBUG: _g_io_module_get_default: Found default implementation dconf (DConfSettingsBackend) for ‘gsettings-backend’
[+0,15s] DEBUG: app-window.vala:1906: Loading state from /home/thomas/.cache/simple-scan/state
[+0,15s] DEBUG: app-window.vala:1885: Restoring window to 587x419 pixels
[+0,55s] DEBUG: app-window.vala:1981: Saving state to /home/thomas/.cache/simple-scan/state
[+3,32s] DEBUG: scanner.vala:1539: sane_init () -> SANE_STATUS_GOOD
[+3,32s] DEBUG: scanner.vala:1545: SANE version 1.0.29
[+3,32s] DEBUG: scanner.vala:1606: Requesting redetection of scan devices
[+3,32s] DEBUG: scanner.vala:828: Processing request
[+3,59s] DEBUG: app-window.vala:1981: Saving state to /home/thomas/.cache/simple-scan/state
[+11,18s] DEBUG: scanner.vala:341: sane_get_devices () -> SANE_STATUS_GOOD
[+11,18s] DEBUG: scanner.vala:353: Device: name="hpaio:/usb/DeskJet_2600_series?serial=CN04U9819F06PS" vendor="Hewlett-Packard" model="DeskJet_2600_series" type="all-in-one"
[+11,45s] DEBUG: app-window.vala:1981: Saving state to /home/thomas/.cache/simple-scan/state
[+11,96s] DEBUG: simple-scan.vala:1536: Requesting scan at 300 dpi from device 'hpaio:/usb/DeskJet_2600_series?serial=CN04U9819F06PS'
[+11,96s] DEBUG: scanner.vala:1674: Scanner.scan ("hpaio:/usb/DeskJet_2600_series?serial=CN04U9819F06PS", dpi=300, scan_mode=ScanMode.COLOR, depth=8, type=single, paper_width=0, paper_height=0, brightness=0, contrast=0, delay=3000ms)
[+11,96s] DEBUG: scanner.vala:828: Processing request

(simple-scan:18139): Gtk-WARNING **: 22:08:10.485: Calling org.xfce.Session.Manager.Inhibit failed: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such method “Inhibit”

(simple-scan:18139): Gtk-WARNING **: 22:08:10.486: Calling org.xfce.Session.Manager.IsInhibited failed: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such method “IsInhibited”
[+11,97s] DEBUG: scanner.vala:889: sane_open ("hpaio:/usb/DeskJet_2600_series?serial=CN04U9819F06PS") -> SANE_STATUS_IO_ERROR
[+11,97s] WARNING: scanner.vala:893: Unable to open device: Error during device I/O
[+12,29s] DEBUG: app-window.vala:1981: Saving state to /home/thomas/.cache/simple-scan/state