KDE Plasma 6.6.3 Fixes Direct Scan-Out Issues with Fractional Scaling

KDE developers continue their rapid pace of development with both Plasma 6.7 feature work and refinements to the current 6.6 stable series. The latest Plasma 6.6.3 update addresses a significant performance issue that affected users employing fractional scaling with direct scan-out displays.

Plasma 6.6.3 Direct Scan-Out Performance Fix

One of the most notable improvements in Plasma 6.6.3 is the reduction in CPU and GPU load for full-screen windows when using direct scan-out mode on displays with fractional scaling factors. This fix addresses a performance bottleneck that could cause unnecessary system resource consumption during fullscreen applications, particularly noticeable during gaming, video playback, or other media consumption scenarios.

The direct scan-out feature allows applications to bypass compositing and render directly to the display, which can improve performance and reduce latency. However, when combined with fractional scaling (non-integer scaling factors like 1.5x or 2.3x), this could lead to increased CPU/GPU overhead as the system struggled to maintain proper rendering across the scaled display.

Plasma 6.7 Feature Highlights

While 6.6.3 focuses on stability and performance, Plasma 6.7 development continues to introduce new capabilities:

Enhanced Keyboard Input: The plasma-keyboard module will introduce a press-and-hold feature similar to smartphone virtual keyboards, allowing users to access additional characters by holding down keys that don't physically exist on their hardware keyboard. This is particularly useful for users needing special characters or those with compact keyboards.

Custom Sound Themes: Users will be able to install custom sound themes directly from downloaded files, expanding personalization options beyond the default system sounds.

USB Printer Notifications: A long-standing annoyance has been addressed - plugging in a USB printer will now generate only a single notification rather than the previous double notification, reducing notification clutter.

Electron App System Tray Fix: A workaround has been implemented for Electron applications with system tray icons that were incorrectly sharing settings with each other. While this is an upstream Electron bug, the Plasma-side fix ensures better behavior for applications using older Electron versions.

Multi-GPU OpenGL Support: For systems with multiple GPUs where one lacks OpenGL acceleration support, Plasma 6.7 will no longer prevent other GPUs from providing 3D acceleration. This change improves compatibility for hybrid GPU setups and systems with mixed-generation graphics hardware.

These improvements demonstrate KDE's commitment to both refining existing functionality and introducing thoughtful new features. The direct scan-out fix in 6.6.3 should be particularly welcome for users who rely on fractional scaling for high-DPI displays while maintaining optimal performance during fullscreen applications.

For more details on these changes and additional developments, visit the This Week in Plasma announcement.