fullscreen uses only 1/4 of screen on secondary monitor with HiDPI scaling

[Mike Gresens]

lsb_release -rd
->
Description: Ubuntu 20.04 LTS
Release: 20.04

apt-cache policy chromium
->
chromium:
  Installiert: (keine)
  Installationskandidat: (keine)
  Versionstabelle:

hardware:
2x monitors: 4K
scaling: 200%

Is:
In chromium the fullscreen-mode uses only 1/4 of the screen on the 2nd monitor.

Should be:
In chromium the fullscreen-mode uses 1/1 of the screen on the 2nd monitor.

[Olivier Tilloy (osomon)]

Could you please run the following command in a terminal to attach additional debug information to this bug?

    apport-collect 1874727

Also, would you mind taking a screenshot/picture that demonstrates the problem? Thanks!

[Mike Gresens (msg-72)]

Unfortunately the command

apport-collect 1874727

runs forever without any progress...

[Olivier Tilloy (osomon)]

Can you try running that command again? Maybe it showed a dialog prompting you to allow attaching the additional information, but somehow that dialog wasn't brought to the front?

Can you confirm that on the primary monitor, chromium uses all the screen for fullscreen (i.e. the problem is only observed on the secondary monitor)?

Is firefox similarly affected?

[Mike Gresens (msg-72)]

apport-collect 1874727 still runs forever...

Yes, on the primary monitor chromium uses 100% of screen.
And firefox uses 100% of screen on both monitors.

So the problem is with chronium on secondary monitor only.

NOTE: If you click into that 25% (e.g. to stop/start video) the fullscreen starts to use 100% of screen.

[Antoine Pintout (procsynth)]

I'm also affected by this problem.

I found some workarounds:
- while staying in "1/4 fullscreen", defocus chromium by selecting an other window, click on the "1/4 fullscreen" -> 1/4 become full
- switching to another Gnome workspace and back to the one with the fullscreen chromium -> 1/4 become full

(I can't run `apport-collect 1874727` : "You are not the reporter or subscriber of this problem report, or the report is a duplicate or already closed.")

[Olivier Tilloy (osomon)]

Thanks for the confirmation Antoine.

This looks like an issue related to the HiDPI scaling factor used (200%).

[Antoine Pintout (procsynth)]

Yes it seems related to HiDPI, in fact this issue appears either with a second monitor or not.
I'm using a laptop with an HiDPI display.

I have the same issue with Google Chrome.

I'm now able to run apport-collect, but it seems to be taking a long time.

[Sebastien Bacher (seb128)]

if chrome has the same issue then the 'snap' in the topic should probably be removed, is it specific to chromium/chrome only or does it happen to other softwares?

[Olivier Tilloy (osomon)]

Good point Sébastien. I've updated the title.

@Mike or @Antoine: would you mind filing an upstream bug at https://crbug.com and sharing the link to it here?

[Antoine Pintout (procsynth)]

Bug reported here :
https://bugs.chromium.org/p/chromium/issues/detail?id=1082763

[Olivier Tilloy (osomon)]

Thanks Antoine.

[Antoine Pintout (procsynth)]

The report I submitted was a dup of https://bugs.chromium.org/p/chromium/issues/detail?id=1055057

I've identified the patch proposed in 1055057 landed in Chrom* 83.0.4102.0, after testing with 83.0.4103.56 the issue is gone!

Thanks!

[Olivier Tilloy (osomon)]

Excellent, thanks for the feedback Antoine.