Bug 476425

Summary:	Wayland client using Krdc results in rendering bug
Product:	[Applications] krdc	Reporter:	Jarrod Farrell <jarrodmaddy>
Component:	VNC	Assignee:	Urs Wolfer <uwolfer>
Status:	RESOLVED FIXED
Severity:	normal	CC:	aacid, ctrlaltca, egzakharovich, jarrodmaddy, kde, smc+kdebugs
Priority:	NOR
Version First Reported In:	23.08.2
Target Milestone:	---
Platform:	NixOS
OS:	Linux
Latest Commit:	https://invent.kde.org/network/krdc/-/commit/a868e291c7548b65c095076a811b55e01009e81e	Version Fixed/Implemented In:	25.04
Sentry Crash Report:
Attachments:	Partially rendered remote display showing the Example.org page Remote display desktop icons vaguely overlaying the local desktop's icons

Description Jarrod Farrell 2023-11-01 16:58:36 UTC

I'm using Plasma Wayland on my desktop and connecting to my laptop, another Plasma Wayland instance, produces a white screen where I can vaguely make out either the remote desktop or elements from my local desktop. Dragging windows over Krdc results in ghosts of the dragged window.

Causing Krdc to fallback to XWayland via the invocation,
WAYLAND_DISPLAY="" krdc
results in the remote display rendering correctly, so there's something wrong with how it renders the connection with Wayland.

STEPS TO REPRODUCE
1. Client machine compositing with Wayland.
2. Using Krdc, connect to a remote VNC server.
3. Behold the personalized white void.

OBSERVED RESULT
Personalized white void.

EXPECTED RESULT
The remote connection's display.

SOFTWARE/OS VERSIONS
Operating System: NixOS 23.11
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.10
Kernel Version: 6.1.60 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800X 8-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 570 Series

Comment 1 Jarrod Farrell 2023-11-01 17:00:00 UTC

Created attachment 162796 [details]
Partially rendered remote display showing the Example.org page

Comment 2 Jarrod Farrell 2023-11-01 17:00:45 UTC

Created attachment 162797 [details]
Remote display desktop icons vaguely overlaying the local desktop's icons

Comment 3 Ryan H. 2024-09-03 17:15:57 UTC

I have observed this and was able to work aroung thisn by disabling hardware acceleration when connecting with RDP.

I am using the following versions on Arch Linux
KDE Plasma 6.1.4
KDE Frameworks 6.5.0
QT 6.7.2
KRDC 24.08.0
freerdp2 2.11.7

Comment 4 Egor Zakharov 2025-01-23 20:26:36 UTC

I can confirm this happening when using RDP, disabling acceleration is a workaround. Installed from Flathub


          ID: org.kde.krdc
         Ref: app/org.kde.krdc/x86_64/stable
        Arch: x86_64
      Branch: stable
     Version: 24.12.1
     License: GPL-2.0+
      Origin: flathub
  Collection: org.flathub.Stable
Installation: system
   Installed: 8.7 MB
     Runtime: org.kde.Platform/x86_64/6.8
         Sdk: org.kde.Sdk/x86_64/6.8

      Commit: a85ae32cc486b743fe6067c3c0026cb1db328eab5c27204ccbdf9065b4024066
      Parent: dad712b1368997f5f5613d077a50d2f085347ecbb670a5716a0779641444f829
     Subject: krdc: Update krdc-24.12.0.tar.xz to 24.12.1 (f79613ad)
        Date: 2025-01-09 23:44:35 +0000