Changes/BetterSwitchableGraphicsSupport

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Contents

Better Switchable Graphics Support

Summary

All modern laptops have a gpu integrated into their processor (the igpu), some models also have a more powerful dedicated gpu (dgpu), this is called switchable graphics. The goal of this feature is to improve Fedora's support for such laptops.

Owner

Current status

Detailed Description

By default all apps will run on the more energy efficient igpu and the OS can choose to switch to the dgpu when more gpu-power is necessary, trading battery time for graphics performance. On most laptops the default gpu can be changed to the dgpu so that everything will always run on the dgpu.

Linux support for switchable graphics currently is not very good. E.g. on many laptops some of the external connectors are only connected to the dgpu and to be able to use those external connectors without issues users need to change the default gpu to the dgpu, resulting in a hot running laptop and the battery draining much faster.

The goal of this feature is to improve switchable graphics support under Linux, allowing the igpu to be used as default, allowing maximum batter life, while keeping everthing working normally. Specifically the following should all work: external outputs, suspend / resume (including suspend/resume with external monitors connected / while docked) and suspending the dgpu when not used.

A secondary goal is to allow people to run graphically demanding programs on the dgpu by starting them with "DRI_PRIME=1 program", note that since we do not support dynamic reclocking of nvidia GPUs this will not always result in a performance improvement.

Benefit to Fedora

Better user experience on laptops with switchable graphics.

Scope

  • Proposal owners: Fix switchable-graphics related kernel and xorg bugs, ensure gnome-control-panel "Displays" setting works properly on switchable-graphics setups
  • Other developers: GNOME control-panel developers (if changes are necessary there)
  • Release engineering: N/A (not a System Wide Change)
  • List of deliverables: N/A (not a System Wide Change)
  • Policies and guidelines: N/A (not a System Wide Change)
  • Trademark approval: N/A (not needed for this Change)

Upgrade/compatibility impact

N/A (not a System Wide Change)

How To Test

  1. Take a laptop with switchable-graphics
  2. Ensure the igpu is the default in the BIOs (Optimus enabled for laptops with nvidia gpus)
  3. Boot Fedora 25
  4. Check that all video outputs work as advertised, and that things keep working after a suspend/resume.

User Experience

Users with a laptop with switchable graphics should now have a smooth experience wrt using e.g. external video outputs. If they were not using the igpu by default before they should now be able to do so without adverse side-effects leading to better battery life.

Dependencies

N/A (not a System Wide Change)

Contingency Plan

  • Contingency mechanism: (What to do? Who will do it?) N/A (not a System Wide Change)
  • Contingency deadline: N/A (not a System Wide Change)
  • Blocks release? N/A

Documentation

N/A (not a System Wide Change)

Release Notes