KDE KWin developer Xaver Hugl published a new blog post today outlining the KMS overlay planes support present within the newly-released Plasma 6.5 desktop. While not yet enabled by default, enabling the overlay planes functionality can result in some nice power savings such as during video playback.
Plasma 6.5’s KWin has the ability to support overlay planes now rather than just the primary and cursor planes. Having overlay planes can be particularly beneficial in terms of power and overall efficiency for video playback, which will now work with Plasma 6.5 when enabled, if using a driver supporting DMA-BUF, and the contents not being modified by any KWin effect and otherwise unobstructed.
For those already on Plasma 6.5, the overlay planes support can be enabled via the KWIN_USE_OVERLAYS=1 environment variable.
Xaver Hugl did some testing of the overlay planes power impact on Plasma 6.5 with a Framework 13 laptop at 50% display brightness. He found rather significant savings across video playback in Firefox as well as the MPV video player:
Even more exciting is the optimization effort isn’t over and there still is the possibility of tapping even more power efficiency gains moving forward.
Those wanting to learn more about Xaver’s work can do so via this blog post. While the KWIN_USE_OVERLAYS=1 environment variable is needed with Plasma 6.5, the hope is that for Plasma 6.6 this might be enabled by default at least for some drivers.
