Without sudo, system-config-printer freeze when changing printer driver

[cshong]

Distribution: Ubuntu MATE 20.04.1 LTS.
System-config-printer version: 1.5.12-0ubuntu1.1

If I run system-config-printer by clicking Menu -> Administration -> Printers, the system-config-printer will be run without prompting for my user password, mean without using sudo. I can install the printers successfully without any issue. But, when changing the driver, system-config-printer will freeze.

Here are the steps to reproduce the issue:

1. Run system-config-printer by clicking Menu -> Administration -> Printers. You will not be prompted to enter any password.
2. Install any printer.
3. Close system-config-printer.
4. Run system-config-printer again by repeating step 1 above, clicking Menu -> Administration -> Printers.
5. Right click on any installed printer, then click properties. Printer properties will be shown.
6. In printer properties, click the "change" button located at the right side of "Make and Model" text field. The "change Driver" dialog will occur.
7. In "Change Driver" dialog, by default, "Select printer from database" will be choosen automatically. Do not do anything, and just wait for a few seconds. Another dialog occur, showing "Searching for drivers".
8. Wait for a few minutes, you will see nothing happen. System-config-printer will continue to hang/freeze.

There is a workaround.

Steps for workaround:

1. Exit system-config-printer if it is still running. If the system-config-printer still hang or freeze, use system monitor to kill it.
2. Run terminal.
3. In terminal run system-config-printer by using command "sudo system-config-printer". You will be prompted to enter your user password.
4. Enter your user password, then press the Enter key.
5. In system-config-printer, right click on any installed printer, then click "properties". Printer properties will be shown.
6. In printer properties, click the "change" button located at the right side of "Make and Model" text field. The "change Driver" dialog will occur.
7. Wait for the "Searching for drivers" dialog to appear and disappear, list of printer brands will be shown.
8. You can proceed to follow on screen instructions to change the driver.

Please fix this issue.

If changing printer driver require sudo, system-config-printer should prompt for my password.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: system-config-printer 1.5.12-0ubuntu1.1
ProcVersionSignature: Ubuntu 5.4.0-54.60-generic 5.4.65
Uname: Linux 5.4.0-54-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.12
Architecture: amd64
CasperMD5CheckResult: skip
CupsErrorLog:
 W [23/Nov/2020:15:45:07 +0800] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id \'DocuCentre_VI_C4471_11_a9_16_-Gray..\' already exists
 W [23/Nov/2020:15:45:07 +0800] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id \'DocuCentre_VI_C4471_11_a9_16_-DeviceN..\' already exists
 W [23/Nov/2020:18:28:39 +0800] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id \'Ricoh-Aficio-MP-201-Gray..\' already exists
 W [25/Nov/2020:07:57:57 +0800] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id \'Ricoh-Aficio-MP-201-Gray..\' already exists
 W [25/Nov/2020:07:59:26 +0800] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id \'Ricoh-Aficio-MP-201-Gray..\' already exists
CurrentDesktop: MATE
Date: Wed Nov 25 08:11:23 2020
InstallationDate: Installed on 2020-11-23 (1 days ago)
InstallationMedia: Ubuntu-MATE 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
Lpstat: device for Ricoh-Aficio-MP-201: socket://192.168.0.226:9100
MachineType: ASUS All Series
PackageArchitecture: all
Papersize: a4
PpdFiles: Error: command ['fgrep', '-H', '*NickName', '/etc/cups/ppd/Ricoh-Aficio-MP-201.ppd'] failed with exit code 2: grep: /etc/cups/ppd/Ricoh-Aficio-MP-201.ppd: Permission denied
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-54-generic root=UUID=cad772fa-c02b-4268-bc15-e366825ac807 ro quiet splash vt.handoff=7
SourcePackage: system-config-printer
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/26/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2603
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: H97-PLUS
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2603:bd02/26/2016:svnASUS:pnAllSeries:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnH97-PLUS:rvrRevX.0x:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: ASUS MB
dmi.product.name: All Series
dmi.product.sku: All
dmi.product.version: System Version
dmi.sys.vendor: ASUS

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.