Bug#1064461: gnome-settings-daemon: Xft.dpi not set correctly for 4K monitor at 200% scale

[Daniel Thompson]

Package: gnome-settings-daemon
Version: 46~beta-1
Severity: normal
X-Debbugs-Cc: debianbugs at redfelineninja.org.uk

Dear Maintainer,

After a relatively routine `apt upgrade` on Debian Trixie I had problems with
all my X11 apps failing to scale correctly.

I'm running gnome-shell/wayland with a 4K monitor at 200% scale. Wayland apps
scale fine but X11 apps (chromium, gvim, etc) and their window decorations are
drawn at 100% scale instead. This appears to be a problem setting up the DPI
configuration for Xwayland.

A simple workaround for most apps is to manually set Xft.dpi:
~~~sh
echo Xft.dpi: 192 | xrdb -merge -
~~~

This will cause X11 application to scale themselves correctly but window
decorations and (some) mouse cursors remain at 100%. I'm not currently aware of
any workaround that will correctly handle the window decorations.

Why is this filed against gnome-settings-daemon?

I reviewed /var/log/apt/history.log carefully and gnome-settings-daemon was
pretty much teh only possibly culprit. I confirmed this by rolling back to
gnome-settings-daemon-45.1-1 and the problem is resolved (and is also why the
system info below shows 45.1-1).

I assume this is a version skew problem caused by gnome-settings-daemon
updating to GNOME 46 before other components and it is possible this problem
will self-correct as other components adopt GNOME 46. However I thought a bug
report would be useful to document the workaround (or rollback) needed for
Debian Trixie at present!


Daniel.


-- System Information:
Debian Release: trixie/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: arm64 (aarch64)
Foreign Architectures: amd64

Kernel: Linux 6.8.0-rc5-00074-gb84349d0e58e (SMP w/8 CPU threads)
Kernel taint flags: TAINT_WARN
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages gnome-settings-daemon depends on:
ii  gnome-settings-daemon-common  45.1-1
ii  gsettings-desktop-schemas     45.0-2
ii  libasound2                    1.2.10-3
ii  libc6                         2.37-15
ii  libcairo2                     1.18.0-1+b1
ii  libcanberra-gtk3-0            0.30-11
ii  libcanberra0                  0.30-11
ii  libcolord2                    1.4.7-1
ii  libcups2                      2.4.7-1+b1
ii  libfontconfig1                2.14.2-6+b1
ii  libgck-1-0                    3.41.1-4
ii  libgcr-base-3-1               3.41.1-4
ii  libgdk-pixbuf-2.0-0           2.42.10+dfsg-3+b1
ii  libgeoclue-2-0                2.7.1-2
ii  libgeocode-glib-2-0           3.26.3-6+b1
ii  libglib2.0-0                  2.78.4-1
ii  libgnome-desktop-3-20         44.0-2+b1
ii  libgtk-3-0                    3.24.41-1
ii  libgudev-1.0-0                238-3
ii  libgweather-4-0               4.4.0-1
ii  libmm-glib0                   1.22.0-3
ii  libnm0                        1.44.2-7
ii  libnotify4                    0.8.3-1
ii  libp11-kit0                   0.25.3-4
ii  libpam-systemd [logind]       255.3-2
ii  libpango-1.0-0                1.51.0+ds-4
ii  libpangocairo-1.0-0           1.51.0+ds-4
ii  libpolkit-gobject-1-0         124-1
ii  libpulse-mainloop-glib0       16.1+dfsg1-3
ii  libpulse0                     16.1+dfsg1-3
ii  libspa-0.2-bluetooth          1.0.3-1
ii  libupower-glib3               1.90.2-8
ii  libwacom9                     2.9.0-2
ii  libwayland-client0            1.22.0-2.1+b1
ii  libx11-6                      2:1.8.7-1
ii  libxext6                      2:1.3.4-1+b1
ii  libxfixes3                    1:6.0.0-2
ii  libxi6                        2:1.8.1-1
ii  pipewire-audio                1.0.3-1

Versions of packages gnome-settings-daemon recommends:
ii  iio-sensor-proxy   3.5-1+b1
ii  pipewire-audio     1.0.3-1
ii  pkexec             124-1
ii  x11-xserver-utils  7.7+10

Versions of packages gnome-settings-daemon suggests:
pn  usbguard  <none>

-- debconf-show failed