hansdegoede | Switchable / Hybrid Graphics support in Fedora 25 (Reply)

Recently I've been working on improving hybrid graphics support for the upcoming Fedora 25 release. Although Fedora 25 Workstation will use Wayland by default for its GNOME 3 desktop, my work has been on hybrid gfx support under X11 (Xorg) as GNOME 3 on Wayland does not yet support hybrid gfx,

So no Wayland, still there are a lot of noticable hybrid gfx support and users of laptops with hybrid gfx using the open-source drivers should have a much smoother userexperience then before. Here is an (incomplete) list of generic improvements:

Fix the discrete GPU not suspending after using an external monitor, halving laptop battery life

xrandr --listproviders no longer shows 3 devices instead of 2 on laptops with 2 GPUs

Hardware cursor support when both GPUs have active video outputs, previously X would fallback to software cursor rendering in this case which would typically lead to a flickering, or entirely invisible cursor at the top of the screen

Besides this a lot of work has been done on fixing hybrid gfx issues in the modesetting driver, this is important since with Fedora we use the modesetting driver on Skylake and newer Intel integrated gfx as well as on Maxwell and newer Nvidia discrete GPUs, the following issues have been fixed in the modesetting driver (and thus on laptops with a Skylake CPU and/or a Maxwell or newer GPU):

Hide HW cursor on init, this fixes 2 cursors showing on some setups

Make the modesetting driver support DRI_PRIME=1 render offloading when the secondary GPU is using the modesetting driver

Fix misrendering (tiled vs linear) when using DRI_PRIME=1 render offloading and the primary GPU is using the modesetting driver

Fix GL apps running at 1 fps when shown on a video-output of the secondary GPU and the primary GPU is using the modesetting driver

Fix secondary GPU video output partial screen updates (part of the screen showing a previous frame) when the discrete GPU is the secondary GPU and the primary GPU is using the modesetting driver

Fix secondary GPU video output updates lagging (or sometimes the last frame simply not being shown at all because no further rendering is happening) when the discrete GPU is the secondary GPU and the primary GPU is using the modesetting driver

Note coming Thursday (November 3th) we're having a Fedora Better Switchable Graphics Test Day, if you have a laptop with hybrid gfx please join us to help further improving hybrid gfx support.