Ubuntu logo vanishes and fades back in on gdm start

[Dimitri John Ledkov]

spinner theme flickers Ubuntu logo on gdm transition

At the end of boot, spinner disappears and Ubuntu logo remains 100% opacity white on screen.

Then GDM starts, and performs a fade-in animation of background gradient, and fade-ins Ubuntu logo.

This results in visual flicker, where Ubuntu logo temporarily dissappears and instantly fades back in.

This should be more smooth. For example, gdm could paint ubuntu logo at 100% opacity white without animation, whilst everything else fades-in. Or we could fade out ubuntu-logo in the spinner plymouth theme, such that on boot it is a tasteful pulsating logo that fades out, and back in.

[Launchpad Janitor (janitor)]

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

[Daniel van Vugt (vanvugt)]

The two Ubuntu logos are also slightly different sizes so that would need to be fixed too.

[Daniel van Vugt (vanvugt)]

To resolve comment #3: https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1101

[Daniel van Vugt (vanvugt)]

Here's an alternate fix for comment #3. Just removing whitespace from the logo (limit it to 48px high) is enough to stop it from getting shrunken by the login screen.

Sorry I can't tell how to make a debdiff of this binary change, or find an SCM to propose it to.

Help?

[Daniel van Vugt (vanvugt)]

xnox,

Here's a tiny gnome-shell patch to stop the Ubuntu logo fading in. Actually right now it looks worse because there's some startup flicker in there still. I'm not sure what that is... :/

[Daniel van Vugt (vanvugt)]

It looks like the remaining flicker could be at least two different issues:

 * gnome-shell often misses the first frame, leaving mutter to display a blank background:
   https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1102
   Unclear if that fix is mandatory for this bug.

 * Asynchronous logo loading, so painting the first frame doesn't wait for it to be loaded.

Good news at least I can't find any problem with mutter. It's all gnome-shell.

[Daniel van Vugt (vanvugt)]

Turns out this is the only patch gnome-shell needs...

[Daniel van Vugt (vanvugt)]

Almost perfect now. There is however a 1px or so shift upward on startup. But we can talk about that after/if the other patches land first.

[Sebastien Bacher (seb128)]

Tagging rls-ff-notfixing, it doesn't mean we should work on it but we decided it's not worth targetting at as a release issue at this point

[Daniel van Vugt (vanvugt)]

When and if we want it, here's a polished distro patch for gnome-shell. Assuming the size issue is also fixed in plymouth via comment #7 or similar.

[Daniel van Vugt (vanvugt)]

To complicate matters, the fix for comment #3 has now landed in upstream gnome-shell 3.36.1. So if we want we can say "Won't Fix" to the now redundant Plymouth fix in comment #7. Or land both because it's more robust to have two fixes (both would have to regress before you noticed a regression).

This bug still needs a second gnome-shell fix though, the main fix which is comment #13.

[Daniel van Vugt (vanvugt)]

Plymouth is now "Won't fix" because the proposed fix in (now hidden) comment #7 was broken by the fix for bug 1866413.

Since the sizing issue is already fixed in gnome-shell 3.36.1 upstream we will wait for that. This bug still requires the separate gnome-shell patch in comment #13 though. That's the main fix for this bug.

[Daniel van Vugt (vanvugt)]

https://salsa.debian.org/gnome-team/gnome-shell/-/merge_requests/38

[Daniel van Vugt (vanvugt)]

https://salsa.debian.org/gnome-team/gnome-shell/-/commits/ubuntu/master

[Launchpad Janitor (janitor)]

This bug was fixed in the package gnome-shell - 3.36.1-4ubuntu1

---------------
gnome-shell (3.36.1-4ubuntu1) focal; urgency=medium

  * Merge with debian, with new upstream releases and cherry-picked fixes:
    - Lockscreen password field is stretched on enter (LP: #1869916)
    - Downscaled lockscreen background with fractional scaling (LP: #1866851)
    - Volume keys doesn't always produce a sound (LP: #1870958)
    - Shell crashes when using show-apps button in dock (LP: #1868659)
    - App folders improvements
    - Don't load app infos in the main thread
  * debian/patches:
    - Refreshed
  * d/p/ubuntu/desktop_detect.patch:
    - No need to include desktop.js into the prefs gresources anymore
  * Remaining changes with debian:
    - Replace gnome-backgrounds dep with ubuntu-wallpapers and Suggests
      gnome-themes-standard-data, gnome-backgrounds
    - Add some Recommends:
      + ubuntu-session (| gnome-session) to have the ubuntu session available
      + xserver-xorg-legacy
      + yaru-theme-gnome-shell for the default ubuntu theming
    - Update debian/gbp.conf with Ubuntu settings
    - gnome-shell-common.prerm: Remove deprecated ubuntu theme alternative
    - ubuntu/desktop_detect.patch:
      + add caching for desktop detection to avoid querying the current
        desktop env variable as iterate through the list each time. For the
        time of the Shell process, we can expect this env variable to stay
        stable.
    - ubuntu/smarter_alt_tab.patch:
      + quick alt-tab (without showing up the switcher) switch only between
        the last window of the last 2 applications to be focused instead of
        raising all windows of those apps.
    - ubuntu/lightdm-user-switching.patch:
      + Allow user switching when using LightDM.
    - ubuntu/lock_on_suspend.patch
      + Respect Ubuntu's lock-on-suspend setting.
    - ubuntu/background_login.patch
      + Change default background color as we modified the default GDM color
        for our ubuntu session.
    - ubuntu/gdm_alternatives.patch
      + Add support for GDM3 theme alternatives
    - optional-hot-corner.patch
      + enable patch proposed by upstream developer already in package (but
        not in series) to add a settings for optional hot corner activation.
    - main-show-an-error-message-on-gnome-shell-crash.patch,
      global-make-possible-to-set-debug-flags-dynamically.patch,
      main-increase-the-granularity-of-backtraces-in-SHELL_DEBU.patch,
      main-add-backtrace-crashes-all-and-backtrace-all.patch,
      sessionMode-add-support-for-debugFlags-parameter.patch:
      + Improve debug JS tracing for crash reports
    - st-scroll-view-Handle-the-case-where-scrollbars-are-NULL.patch:
      + Fix crash on theme changes
    - ubuntu/search-call-XUbuntuCancel-method-on-providers-when-no-dat.patch:
      + stop searches when requested from UI
    - magnifier-Show-cursor-when-magnifier-is-enabled-and-scale.patch:
      + Show monitor scaled cursor when magnifier is enabled
    - Break gnome-shell-extension-desktop-icons (<< 19.01.3+git20190814)

  [ Daniel van Vugt ]
  * d/p/ubuntu/keep-ubuntu-logo-bright-lp1867133-v1.patch:
     Stop the Ubuntu logo f...