Desktop Team Updates - Monday 30th August 2021

Hi everyone, below you will find the updates from the Desktop team from the last week. If you’re interested in discussing a topic please start a thread in the Desktop area of Discourse.

Last week’s notes are here: Desktop Team Updates - Monday 23rd August 2021

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  • 20.04.3 Release testing: WSL and Desktop.
  • Started to draft the roadmap for Ubuntu on WSL for next cycles.
  • Triaging bugs on customer project.
    • reviewing current MP.
    • Fixed the last stage and the progress so the system setup finishes.
    • Wrote an integration test and added to the test suite.
  • Lots of bug management in Launchpad and upstreams. [Backlog stats]
  • Finally gave in and proposed patches to gnome-shell and ubuntu-dock that will prevent GNOME 40 logging into the overview.
  • Spent all week bisecting the kernel/plymouth shutdown regression. After all that it’s probably still Plymouth that’s more buggy and it just didn’t matter prior to the Intel graphics change in kernel 5.11.
  • Packaged and tested the BlueZ 5.61 release at Seb’s request. Although we probably won’t need it till 22.04 so it can stay in a separate branch for now.
  • Triple buffering progress:
    • Resolved more discussions.
    • Implemented downclocking to double buffering based on when render times are sufficiently low. This makes upclocking a bit slower but not visibly in my testing and it’s better at sticking to double buffering during fast desktop interactions. Another bonus of this approach is that it will be reusable to solve direct scanout (soon).

Ubuntu Desktop Installer

WSL Setup Wizard


  • Spent a lot of time on preparing for the indaba. I worked with Till quite a bit to better understand the printing stack and draft some representative pictures of the IPP printing stack in Inkscape.
  • In my work in inkscape, I encountered a bug that I then spent some parallel time investigating. Trying to replicate the problem, I built the INKSCAPE_1_0_1 and INKSCAPE_1_0_2 tags locally and did some testing but ultimately I built these on a couple of systems and installed them and still had runtime issues launching the program. So something is messed up with these tags. I will keep going back to find a tag that builds and runs to try and reproduce the bug I filed to give some more reproducible steps to the bug owner.
  • Robbie ping’d me on a gnucash bug I’d filed for a prev +1 maint… I had submitted a PR to debian but then never got notified and forgot about it… so went and refreshed the patch a couple of times and it’s ready for re-review.
  • @jibel ping’d me on a network-manager bug. I looked into it and read through JB’s patch and looks good. Just need to test that this fixes the issue and prepare a debian patch with this 10-timesyncd patch attached. Will get that done this week.
  • To prepare for Grace Hopper (Sept 27 - Oct 1), I took a booth training thing and signed up for a couple of half day booth duties
  • LO snap 7.2.0 new build in edge. about to promote to stable.
  • GNOME bugfix updates
  • Fixed some FTBFSes
  • snaps
    • updated thunderbird candidate to 91.0.3
    • updated thunderbird beta to 92.0b3
  • reviews
    • sponsored alsa-ucm-conf fixes and SRU from oem
    • reviewed and tested the changes from mwhudson to how to desktop iso language layers are built
  • CUPS Snap: Waiting for @ijohnson’s pull request on snapd for the cups printing interface to get merged by the snapd team.
  • pappl-retrofit: During the development of the Ghostscript Printer Application added some missing features, especially to support multiple drivers for the same printer model. For this we use regular expressions to clean the driver names in the make/model/driver list and to prioritize drivers for auto-setup. Also so “Generic” printer/driver entries at the top of the list and added a function to check whether a printer is PCL 5c (color PCL5) to not assign a monochrome driver to a color printer. Fixed several bugs, including a crasher and explained how to use the included Test Printer Application in
  • Ghostscript Printer Application: Launched the second CUPS-driver-retro-fitting Printer Application on GitHub and in the Snap Store (already 18 Snap downloads from Friday to now). This one retro-fits mainly Ghostscript’s built-in drivers but also some others, practically all available non-PostScript drivers for which the PPDs come with the foomatic-db Debian package (the PostScript printers are covered by the PostScript Printer Application). Got kudos from Zdenek Dohnal (Red Hat) for it.
  • PostScript Printer Application: Minor fixes and adaptations along with the further development of pappl-retrofit and the Ghostscript Printer Application. Added support for Resolution and Color Mode to the Generic PPD.
  • HPLIP Printer Application: Started work on retro-fitting at least the printer driver (scanning support in PAPPL not yet completed) of HPLIP into a Printer Application. Created already a discovery CUPS backend for network printers (HPLIP’s hp backend only discovers USB printers) and started investigations about downloading the proprietary plugin.
  • cups-filters: Needed for the Ghostscript Printer Application added support for driver info separation from PPD’s NickName entry and in the IPP->PPD-preset generator support for composite options (Foomatic’s “presets”) and variations of Economy mode in Foomatic’s PPDs. Received a lot of contributions from the GSoC students: bannertopdf turned into a filter function and working without PPD files, print-rendering-intent IPP attribute support in the filters, color management functions correctly logging into log functions instead of spilling into stderr. Got pull request for converting texttotext into a filter function.
  • Google Summer of Code 2021: It is successfully completed now! All the 5 students have passed the final evaluations. In the final evaluations of the mentors by the students I got kudos from all the 4 students who I mentored.
  • Ubuntu Indaba: Worked with @hellsworth on the infographics for the presentation about current and future CUPS printing workflows. After the video meeting in the beginning of last week I also did a write-up and with that @hellsworth created the Inkscape drawings for the 3 workflow scenarios. The Indaba has taken place on Friday afternoon (Recording on YouTube) with Michael Sweet (author of CUPS, PAPPL, and good part of IPP) and me not only explaining the 3 CUPS printing workflows (PPD + driver filter, driverless IPP printer, Printer Application) but also giving a historical background of free software printing. After that we answered user questions. Got kudos from @kenvandine and @rhys-davies. Aveek Basu posted it on LinkedIn, I posted it in an OpenPrinting News Flash. Thanks to @hellsworth and @rhys-davies for the organization and hosting and to Michael Sweet for participating and his great presentation including giving historic background (Adobe stopped developing on the PPD file format in 1984(!), so it is really time to do away with them).
  • Linux Plumbers Conference 2021: The OpenPrinting Micro-Conference will take place on Mon, September 20, 2021.
  • OpenPrinting: The OpenPrinting web server (which hosts the printer/driver database, static pages, news posts, … are hosted by GitHub) got switched over to a new server (old one was still on Ubuntu 12.04). Still has some issues which I am sorting out with the admin. Also answered some user mails about working around the case that they could
    not download Ricoh printer PPD files. Told them to get them from foomatic-db on GitHub or use the PostScript Printer Application.
  • OpenPrinting: After this busy week full of interesting new stuff I did not want to let the users wait more two weeks for the September New Post and posted an extra News Flash.
  • Bugs.

firefox24 firefox

thunderbird24 thunderbird

chromium22 chromium


Just 4 working days after holidays last week (and 2 more this one)… So mostly backlog stuff


  • libfprint, some upstream reviews
  • Updated libfprint-tod to new upstream version, keeping ABI compatibility with old drivers [commits].
    • Added more abi tests for further drivers compiled with different tod versions
  • Looked at GDM updates needed for proper nvidia support
  • Rebased various branches that I’ve proposed some weeks ago and that needed manual love
  • Used more python-dbusmock in mutter tests [MR]
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