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12 December 2016 @ 06:13 pm
Hybrid graphics and NVidia binary driver support in Fedora 25  
As blogged about already by Christian for Fedora 25 we've been working on improving hybrid gfx support, as well as on making it easier for users who want to, to install the NVidia binary driver.

The improved hybrid gfx support using the default opensource drivers was ready in time for and is part of the Fedora 25 release. Unfortunately the NVidia driver work was not ready in time. This has lead to some confusion.

Let me start with a FAQ to try and clarify things:

1)  I want to use Fedora 25 on a laptop with hybrid graphics, will this work?

Yes Fedora 25 supports hybrid graphics out of the box using the opensource drivers included with Fedora. A lot of work has been done to make this as smooth as possible. If you encounter any problems with hybrid graphics under Fedora 25 using the default opensource drivers, please file a bug in bugzilla and put me in the Cc.

2) I want to use the NVidia driver with Fedora 25, I heard it would be available in gnome-software?

It is our intend to make the NVidia driver available in gnome-software (for users who have 3th party sources enabled), but this is not ready yet, I hope to announce some progress on this on this blog soon. see below for a progress report on this.

3) I've an NVidia GPU which driver is better for me?

If you want maximum performance for e.g. gaming, you will likely want the NVidia driver. But be aware that on Optimus laptops using the NVidia driver will result in much higher power consumption / shorter battery life, as all rendering then is done on the NVidia GPU, which means that it cannot be powered down while your doing light work.

If your workload does not need maximum 3D rendering performance your likely better of with the default opensource drivers. On Optimus laptops these offer much better batery life and the opensource drivers do not have the risk of breaking when upgrading your kernel, or upgrading to the next Fedora release.

4) I want to have good battery life, but I also want to play the occasional game with good performance?

As part of the work on making it easy to use the NVidia driver with Fedora, I'm also planning to add a utility which will allow you to easily switch between nouveau and the NVidia driver. Note this will require a reboot each time you switch.

5) What is the status of making the NVidia driver available for easy installation in Fedora 25?

This biggest issue with the Nvidia driver is that it will not work out of the box on optimus enabled laptops, installing it on such a laptop will typically result in the laptop booting to a black screen, which is NOT the user experience we want to offer.

I've just finished a set of patches for the xserver, which will allow the NVidia driver rpm to install a xorg.conf snippet which will make the xorg autoconfigure code automatically set things up the right way for the nvidia driver on optimus enabled laptops.

Depending on the upstream review of these patches I will prepare an updated xserver package with these patches for Fedora 25 soon. Once that is in place, the negativo17.org rpms can be updated with the xorg.conf snippet.

When that is done, there still are some other issues to tackle:

  • Mesa in F25 is not yet glvnd dispatch enabled, which means that the negativo17.org rpms need to play ldconfig path tricks, which means that if the rpms get installed on a system with an unsupported GPU, and Xorg falls back to the open-source driver things go boom because apps end up loading the wrong libGL.so

  • We want to have some mechanism in place to automatically load the nouveau kernel-module before starting gdm if the nvidia kernel module did not load for some reason (e.g. it failed to compile against a new kernel)

  • The negativo17.org rpms currently use dkms or akmod, building the nvidia kernel module from source on your system, we want to switch things over to having pre-built kmods available

Note not all of these are necessarily blockers for adding the Nvidia driver
to gnome-software.

6) I want to try out the nvidia driver now, is that possible ?

First of all, if you've an optimus enabled laptop, please do not do this (yet), we should have a solution ready for you in a couple of weeks.

If you have a system which is only using a *single* nvidia GPU, then you can install the nvidia driver using the following commands:

  sudo dnf update 'kernel*'
  sudo dnf config-manager --add-repo=http://negativo17.org/repos/fedora-nvidia.repo
  sudo dnf install nvidia-settings kernel-devel dkms-nvidia vulkan.i686 nvidia-driver-libs.i686

Then reboot and you should be running the nvidia driver, to get back to the opensource driver do:

  sudo dnf remove nvidia-driver