https://bugs.kde.org/show_bug.cgi?id=528002
--- Comment #2 from jajaX <[email protected]> --- ## Additional technical information – Two affected laptops, software comparison and troubleshooting I would like to provide additional information about this HDMI regression, which affects two different laptops with nearly identical hybrid Intel/NVIDIA graphics configurations. ### 1. Regression introduced with Plasma 6.8.0 Both laptops worked correctly before upgrading to KDE Plasma 6.8.0, including their external HDMI displays under Wayland. The HDMI corruption appeared after upgrading to Plasma 6.8.0 and persists with Plasma 6.8.2 / KWin 6.8.2. The same hardware works correctly under X11, without the HDMI image corruption observed under Wayland. ### 2. Hardware and display configurations **PC1 – Quadcore** - Hybrid Intel HD 3000 + NVIDIA GF108M graphics - Intel driver: i915 - NVIDIA driver: nouveau (open-source community driver) - Triple-display configuration: - Internal laptop display - External VGA monitor - External HDMI display - NVIDIA GPU handles HDMI - Intel GPU handles VGA - HDMI image corruption under Wayland **PC2 – ASUS K93SM** - Intel HD Graphics 3000 [8086:0126], driver: i915 - NVIDIA GF108M [10de:0de9], driver: nouveau - Dual-display configuration: - Internal laptop display - External HDMI TV - NVIDIA GPU handles HDMI - HDMI image corruption under Wayland Both machines reproduce the same issue despite using different display configurations. ### 3. Software version comparison | Component | PC1 – Quadcore | PC2 – ASUS K93SM | |---|---|---| | Distribution | KDE neon | KDE neon | | Linux kernel | 7.0.0-38-generic | 7.0.0-42-generic | | KDE Plasma | 6.8.2 | 6.8.2 | | KWin | 6.8.2 | 6.8.2 | | KDE Frameworks | 6.31.0 | 6.31.0 | | Mesa | 25.3.6 | 25.3.6 | | libdrm | 2.4.134 | 2.4.134 | | libdrm-nouveau | 2.4.134 | 2.4.134 | | Graphics session affected | Wayland | Wayland | Both laptops use the same Mesa, libdrm and KDE Frameworks versions, but different Linux kernel revisions. The HDMI corruption persists with both kernel 7.0.0-38 and 7.0.0-42. This does not rule out a kernel or driver issue, but demonstrates that upgrading between these kernel revisions does not resolve the problem. ### 4. Troubleshooting already performed The following checks and tests have been performed: - Confirmed the regression on two separate laptops. - Tested different display configurations (dual and triple display). - Confirmed that HDMI worked correctly before Plasma 6.8.0. - Confirmed that HDMI works under X11. - Confirmed that the issue persists under Wayland with Plasma 6.8.2. - Verified that both Intel i915 and NVIDIA nouveau drivers are loaded. - Verified DRM device mapping on PC2. - Checked KWin and DRM-related journal messages. - Confirmed that the internal laptop display works normally while HDMI is corrupted. - Checked the software versions of both machines. - Captured and attached photographs showing the HDMI corruption. No reliable workaround has been identified so far. ### 5. DRM and OpenGL diagnostics on PC2 The DRM device mapping is: - `/dev/dri/card1`: NVIDIA GF108M (nouveau) - `/dev/dri/card2`: Intel HD 3000 (i915) `KWIN_DRM_DEVICES` is not explicitly configured. KWin reports: ``` drmSetClientCap for Atomic Mode Setting failed. Using legacy mode on GPU "/dev/dri/card1" ``` And: ``` Invalid framebuffer status: "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT" ``` The framebuffer warning was observed during KWin startup. No additional matching errors were found in the user journal during a subsequent reproduction of the HDMI corruption. The relationship between these messages and the graphical corruption has not yet been established. ### 6. Observed behavior Under Wayland, the HDMI display shows: - Repeated horizontal sections of the desktop - Severe graphical distortion - Incorrect colors and graphical artifacts - Large black areas - Changes in the corruption pattern while the display is active The laptop's internal display remains usable. Two photographs documenting the issue have been attached to this report. ### 7. Relationship to bug #527163 This regression may be related to: https://bugs.kde.org/show_bug.cgi?id=527163 However, that report was marked as fixed, while the HDMI corruption remains reproducible with Plasma 6.8.2 on this older Intel/Nouveau hybrid GPU configuration. The purpose of this report is to document the remaining issue specifically affecting NVIDIA GF108M with the nouveau driver. ### 8. Further investigation Both GPUs are required for normal multi-display operation. Permanently disabling either GPU is not an acceptable workaround. I am available to perform additional tests involving KWin DRM settings, GPU rendering priority, buffer sharing or diagnostic patches, if requested by the developers. Please let me know if additional logs or system information would be useful. Thank you for your work on KDE Plasma and KWin. -- You are receiving this mail because: You are watching all bug changes.
