Qt 5.0 Is Going To Like LLVMpipe, Wayland

A Qt 5.0 discussion was held in Oakland on Monday.

Of the interesting mentions during the Qt 5.0 discussion was about Wayland and LLVMpipe. In terms of Wayland, it's already widely known that the Qt 5.0 tool-kit will have first-rate support for the Wayland Display Server. Nokia and Intel developers have been working on the Wayland-Qt5 support for months. During the Ubuntu Developer Summit session in Oakland, they basically reiterated that Wayland is being treated as one of their reference platforms. With being a reference platform for Qt, it will ensure good testing (it's these platforms that make up their continuous integration system) and that when new features are added to Qt, support will be a priority for these platform back-ends.

While talking about Wayland at UDS-Q, it's worth mentioning that on Wednesday there is going to be a "system compositor" session. For Ubuntu 12.10 they're looking at using a compositor to control video from boot to shutdown. The reported benefits they're trying to push are using smooth transitions from the splash screen to the greeter (what Plymouth claimed back in the day), VT switching is just problematic, one consistent monitor layout for all stages of the boot, a greeter as the lock screen, no ability to accidentally switch to locked sessions, and showing a greeter while the session is loading. This system compositor they want to use is obviously Wayland.

This Wayland work for Ubuntu 12.10 will basically come down to being a tech preview that they originally hoped for with Ubuntu 12.04 LTS. However, it's rather unlikely that Wayland will be in really usable form for Ubuntu 12.10, especially given Canonical's lack of upstream involvement on Wayland/Weston and the graphics driver dependencies. There will continue to be X11-fallback for the foreseeable future, but I still don't see Wayland support in Ubuntu going beyond an experimental state until at least Ubuntu 13.04. More details on the Ubuntu Wayland stuff tomorrow from the system compositor discussion.

Also talked about for Qt 5.0 and Wayland was the software rasterization method for this first major tool-kit upgrade in seven years. The Qt developers praised the CPU-based Gallium3D driver and will be relying upon LLVMpipe when no GPU hardware driver is available. They say that using LLVMpipe is working better than any software rasterizer of their own.

LLVMpipe remains too slow for OpenGL gaming even with the very latest $999 USD Intel CPUs, but it's good enough for a tool-kit and composited desktop. GNOME Shell runs fine on LLVMpipe even with only a modest CPU and no GPU driver support. Various other projects have also had their eye on LLVMpipe as a software fallback, like Firefox for software WebGL.

While this is all great news and just some of what's exciting about Qt 5.0, if you didn't hear, the final release is delayed to August.