After upgrading from Fedora 40 to 41 (KDE spin) colors are wrong via xrdp (not an XRDP bug)

[sshockley]

xrdp version

0.10.1

Detailed xrdp version, build options

xrdp 0.10.1
  A Remote Desktop Protocol Server.
  Copyright (C) 2004-2024 Jay Sorg, Neutrino Labs, and all contributors.
  See https://github.com/neutrinolabs/xrdp for more information.

  Configure options:
      --build=x86_64-redhat-linux-gnu
      --host=x86_64-redhat-linux-gnu
      --program-prefix=
      --disable-dependency-tracking
      --prefix=/usr
      --exec-prefix=/usr
      --bindir=/usr/bin
      --sbindir=/usr/sbin
      --sysconfdir=/etc
      --datadir=/usr/share
      --includedir=/usr/include
      --libdir=/usr/lib64
      --libexecdir=/usr/libexec
      --localstatedir=/var
      --runstatedir=/run
      --sharedstatedir=/var/lib
      --mandir=/usr/share/man
      --infodir=/usr/share/info
      --enable-fuse
      --enable-pixman
      --enable-painter
      --enable-vsock
      --enable-ipv6
      --with-socketdir=/run/xrdp
      --with-imlib2
      build_alias=x86_64-redhat-linux-gnu
      host_alias=x86_64-redhat-linux-gnu
      CC=gcc
      CFLAGS=-O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Wno-complain-wrong-lang -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64 -march=x86-64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -mtls-dialect=gnu2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer 
      LDFLAGS=-Wl,-z,relro -Wl,--as-needed  -Wl,-z,pack-relative-relocs -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -Wl,--build-id=sha1 -specs=/usr/lib/rpm/redhat/redhat-package-notes 
      CXX=g++
      CXXFLAGS=-O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64 -march=x86-64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -mtls-dialect=gnu2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer 
      LT_SYS_LIBRARY_PATH=/usr/lib64:
      PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig

  Compiled with OpenSSL 3.2.2 4 Jun 2024

Operating system & version

Fedora 41 KDE spin

Installation method

dnf / apt / zypper / pkg / etc

Which backend do you use?

tigervnc-server-minimal-1.14.1-2.fc41.x86_64

What desktop environment do you use?

KDE

Environment xrdp running on

Hyper-V VM

What's your client?

Hyper-V enhanced connection

Area(s) with issue?

Graphic glitches

Steps to reproduce

After upgrading from Fedora 40 to 41, colors when logging in with XRDP were wrong; blue and orange were swapped, at least. Logging in from the non-enhanced console was fine.

This appears to be related to novnc/noVNC#1715, which in turn is caused by https://bugreports.qt.io/browse/QTBUG-108558. Since the bug was filed in 2022 I don't hold much hope for a fix.

I was able to work around this by uncommenting xserverbpp=24 under [Xvnc] and restarting XRDP.

✔️ Expected Behavior

No response

❌ Actual Behavior

No response

Anything else?

Mostly I wanted to file a bug so if others have the same problem they can at least find the workaround. Also for me to find when this happens later and I've forgotten about this.

If there's nothing relevant here for XRDP, please go ahead and close it. Thanks.

[matt335672]

Hi @sshockley

Thanks for filing this, particularly for the workaround.

I think you're right in that this is unlikely to be an xrdp bug, as you're using the VNC backend to provide the desktop. In this mode we do little more than take the VNC server output and convert it to RDP.

Another thing you could try (if you've got the time) is to install the xorgxrdp package and use the Xorg backend. That's likely to have the same problem if this is a Qt issue however.

[LifeTimeCoder]

I am using xorgxrdp backend with Fedore 41 KDE and I have same problem.
I am connecting from Windows 11 and tried with Remote Desktop Connection manager and also new Windows 11 Remote Desktop app

[matt335672]

That makes the Qt issue the likely culprit.

That same workaround should fix it too (I think).

[LifeTimeCoder]

Tried but didn't work

[matt335672]

@LifeTimeCoder - which back end are you using?

[LifeTimeCoder]

For Xrdp I use Xorg

[matt335672]

Having a think about this, there may be no workaround for the Xorg backend in xrdp - the bpp for this server type is fixed.

[LifeTimeCoder]

I've noticed that Firefox is working fine with accurate colors, whereas Chrome might be the culprit here.