Re: is Wayland/Weston mature enough to be the default desktop choice in Buster?

[Guillem Jover <guillem@debian.org>]

On Sat, 2019-04-06 at 21:48:57 +0200, Bastian Blank wrote:
> On Sat, Apr 06, 2019 at 08:47:51PM +0200, Guillem Jover wrote:
> > I don't use GNOME at all, but I tried to switch to Wayland last month
> > (from i3 to sway), and sadly the experience lasted only a couple of days.
> 
> You changed display manager implementations and are trying to compare
> that?

Well it was obviously easier to compare than against Weston/GNOME/KDE.

> How can you differentiate between problems causes by the i3 to
> sway switch from problems caused by xorg to wayland?

Because the problems I listed were the ones that are obviously
Wayland-related/specific or because I tried with Xwayland and native
support. And because I think all sway-specific problems I found had
already bugs filed.

> > I noticed that not all big desktop programs support Wayland natively
> > (such as Chromium), or do so out of the box (such as Qt or KDE), this
> > implies you need to have XWayland running most of the time, which
> > consumes around 100 MiB of resident memory.
> 
> My gnome-shell consumes a multiple of that usualy.  But much more
> important: why is the qt wayland support not installed?

On my main system that's way too much memory used, and i3 and sway
consume just a fraction of that.

For Qt, qtwayland5 is just a Suggests from libqt5gui5, and a Recommends
from libkf5windowsystem5, or Depends from kwayland-integration via a
Recommends from libkf5windowsystem5|libkf5idletime5.

Even then, AFAIR Qt does not enable Wayland support by default, and it
might need the following environment variables:

  # KDE
  export XDG_SESSION_TYPE=wayland
  export QT_QPA_PLATFORM=wayland-egl

I also tried to play with:

  export QT_WAYLAND_FORCE_DPI=physical

I also used:

  # Gtk3 (this might crash chromium f.ex.)
  export GDK_BACKEND=wayland
  export CLUTTER_BACKEND=wayland
  # SDL
  export SDL_VIDEODRIVER=wayland

(For a tailing WM you might also want:

  export QT_WAYLAND_DISABLE_WINDOWDECORATION=1
  export _JAVA_AWT_WM_NONREPARENTING=1
?)

So, are you sure you are not running Qt apps via Xwayland? To make
sure I disabled Xwayland support to see what was not starting at all,
as I wanted as much as possible to be running natively, to check if
it was feasible to run w/o Xwayland.

> >                                             Wayland also uses libinput
> > which I've found to be subpar compared to the synpatics input drivers.
> 
> xorg only installs the libinput and the separate wacom input by default:

Sure, and I've tried libinput with X.Org and for me it's the same subpar
experience as on Wayland. The difference is that with X.Org I can install
the synaptics driver.

> > There seems to be also some issue with Qt/KDE programs and text DPI.
> 
> I don't see such problems, and I use it in HiDPI mode, which becomes
> increasingly more common.  wireshark is now a Qt application and looks
> fine, apart from the fact that it's Qt and the design choices of this
> library.

See above?

> I could add a number of problems I found myself, but none of them are
> relevant for Joe Random user.

I think I qualified my reply enough as to what was relevant to the
discussion and to what extent I care about the GNOME default? :)
Dunno, just felt like commenting on my attemps as someone who really
wants to switch away from X.Org, but didn't find it satisfactory yet.

Regards,
Guillem