SUMMARY Using an nvidia wayland session, panels and windows do not render with transparency, they appear as though compositing is disabled. STEPS TO REPRODUCE 1. Start a nvidia wayland session 2. Move a window below a plasma panel to try to observe transparency OBSERVED RESULT There is no change in the panel appearance. EXPECTED RESULT The panel modifies its appearance based on the window behind it.
I sent a bug report a few months ago and seems to be a nvidia driver issue. But also seems that Nvidia is updating their driver for best wayland and xwayland support. https://www.phoronix.com/scan.php?page=news_item&px=NVIDIA-DMA-BUF-Wayland-KDE https://www.phoronix.com/scan.php?page=news_item&px=NVIDIA-GL-VLK-XWayland Sorry for my english.
The nvidia driver (up to 465) does not support querying the texture format of wayland textures via EGL_TEXTURE_FORMAT. Depending on the texture format Kwin determines for a window whether it should use an alpha channel or not. If the query fails, it currently defaults to no alpha channel. For nvidia users it would be better if it defaults to assume an alpha channel for all windows. This would help to make transparent windows work better (e.g., latte dock has a black background for me) and allow for the blur effect.
Fixed with https://invent.kde.org/plasma/kwayland-server/-/merge_requests/294