Desktop Team Updates - Monday 9th 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 2nd August 2021

  • Applications review for the position of WSL Engineer
  • Stats from ubuntu-report on CPU HW capabilities
  • Verification of the “Recovery key feature” backported to 20.04 and fixed crash found during testing when partitioning is done manually.
  • Testing WSL OOBE text UI.
  • updated pulseaudio to the new 15.0 version including bluetooth LDAC and AptX codecs and HFP profiles
  • fixed an upgrade issue with the previous upload
  • updated the thunderbird beta snap to 90.1b6
  • tested and promoted a new revision of the desktop installer
  • short week with 3 vac days
  • Applications and tech review for the position of WSL Engineer
  • Backport of the “Recovery key feature” to 20.04.
  • Follow/read WSL documentation and videos.
  • Documentation part 2 training

firefox24 firefox

  • preparing 91.0 update, due for release later today

thunderbird24 thunderbird

  • preparing 78.13.0 update
  • started packaging 91.0 beta builds, to become the next stable series (together with firefox ESR)

chromium22 chromium

  • updated stable to 92.0.4515.131
  • updated dev then beta to 93.0.4577.18
  • updated dev to 94.0.4595.0

snapcraft24 snaps

flutter24 Ubuntu Desktop Installer

  • CUPS Snap: Waiting for @ijohnson’s pull request on snapd for the cups printing interface to get merged by the snapd team.
  • cups-filters: Implementation of CUPS backend support in retro-fitting Printer Applications on the cups-filters side: Added support for side channel and back channel for filters (here filter functions now) and backends to communicate (back channel to pass data returned by the printer back to the filters, side channel for the filters to send queries/commands to the backend and receive the answers from the backend). Added support for running CUPS backends to the filterExternalCUPS() filter function. Also investigated the handling of the orientation of the sheet back sides when printing double-sided. As the turning/flipping of the back side should only once in the filter chain (usually on rendering: gstoraster(), pdftoraster(), …) removed the (already incomplete) back side orientation handling from the pwgtoraster() filter function. Several smaller fixes and clean-ups, especially in the newly contributed code from the GSoC students.
  • Retro-fitting of classic CUPS drivers into Printer Applications: Continued on the driver retro-fit library code. This time started the coding for the CUPS backend. Studied how additional devices/schemes are added to PAPPL-based Printer Applications, and how CUPS runs all its backends in discovery mode on requests like lpinfo -v.
  • Ghostscript: Fixes for the bug raster-only PDF and PCLm output need seekable output device got committed. Also discussed backside orientation with the Ghostscript developers on their new Discord platform.
  • Google Summer of Code 2021: Continued mentoring the students. Got the pdftoraster() filter function working without PPD files, texttopdf got turned into a filter function, and the new texttopdf() got already tested in the universal CUPS filter.
  • Ubuntu Indabas: We got Michael Sweet, author of CUPS and creator of the Printer Application concept, as guest for the upcoming Indaba! Indaba with Michael Sweet and me as guests is announced. Thanks, @hellsworth! Looking forward for Fri, Aug 27, 5pm UTC!
  • Bugs.


  • Some hacking on XServer to get it notify DRM property changes when such changes
    are caused by kernel (as per the privacy screen support work)
  • Added support to destination_keyword to python-dbus signal emission decorator [MR]
  • Addressed comments on mutter orientation changes fixes MR
  • libfprint reviews
  • Upstreamed (and wrote various unit tests) to the IIO Sensors Proxy dbus mock template [PR]
  • Spent a bunch of time on writing a diversity and inclusion discussion guide for Canonical
  • Wrapped up action items from last Indaba and setup the next one
  • Tested and released LO 7.1.5 snap to the stable channel
  • Tested LO 7.2.0 snap (it’s in edge) - fonts look wonky but it runs!

snapd theme support:

  • snapd PR #10574 (make the desktop interface grant access to user GTK CSS) was merged.
  • completed the spread tests for snapd PR #10571 (make snapd theme API available to snaps without plugging snapd-control). This received a first review, but is still waiting on a second.

snapd polkit support:

  • Created snapd PR #10219 as a draft. This implements a polkit-agent interface for snapd that allows a snap to act as a polkit agent. This is intended only for Ubuntu Core systems, as we can’t reasonably make it work on classic systems. In its current form, it is enough to allow gnome-shell to act as an agent on the Ubuntu Core Desktop prototype image.
  • The current version of the interface relies on running polkit-agent-helper-1 unconfined. The eventual aim is to have the helper run under an AppArmor sub-profile customised to the helper’s needs. I’m still working towards getting that implemented.