Radeon

Xf86-video-ati

Radeon is the Linux open-source graphics driver for AMD/ATI Radeon graphics cards that is often replaced by fglrx due to seemingly poor 3D acceleration.

The performance issues are generally caused by generic Xorg profiles which have to cater to a myriad AMD GPUs with a different feature-set and capabilities, forcing them to only enable features that are common to most cards, or none at all (thus, the driver works as is).

Building from source

This guide will attempt to improve 3D acceleration (or outright enable it, if it's disabled) by making use of the new feature-set, namely, DRI3.

Warning: This is quite bleeding edge and might not work. Should it fail, you will be on your own.

Before starting

Check your cards feature-set: https://wiki.freedesktop.org/xorg/RadeonFeature/#index6h2 "Decoder ring for engineering vs marketing names" will tell you what model your card actually is.

Back your xorg.conf up by issuing sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf~

What should I expect?

Run: vblank_mode=0 glxgears & sleep 16 ; killall glxgears.

Test	GPU	Before	After
glxgears	r9 280x (gigabyte)	3258.964 FPS	19291.922 FPS

glxgears is a very simple test and it won't give you real world results, but you can use it to test a driver's 3D performance relative to another one. As you can see here, the results speak for themselves and indicate a performance increase of roughly 560%. For a real-world focused benchmark, scroll down—in CPU bound scenarios you are likely to see performance increases of up to 40%.

Requirements & dependencies

X.Org Server 1.17 (not absolutely necessary, but recommended for stability) media-libs/mesa (the newest version you can find, I recommend the latest one: scroll down the page for more on this)

`--  media-libs/mesa  (>=11.0, preferably -git[1])
`--  x11-libs/libdrm  (>=2.4.58, preferably -git[2], since this is the library DRI uses)
`--  x11-libs/libpciaccess (>=0.8.0)
`--  x11-base/xorg-server (ideally, >=1.17)
`--  x11-libs/glamor (>=0.6)
`--  virtual/udev
`--  x11-proto/fontsproto
`--  x11-proto/randrproto
`--  x11-proto/renderproto
`--  x11-proto/videoproto
`--  x11-proto/xextproto
`--  x11-proto/xf86driproto
`--  x11-proto/xproto
`--  sys-devel/automake  (>1.15)
`--  sys-devel/autoconf  (>=2.69)
`--  sys-devel/libtool  (>=2.4)
`--  sys-devel/m4
`--  x11-misc/util-macros  (>=1.18)
`--  media-fonts/font-util  (>=1.2.0)
`--  virtual/pkgconfig
`--  x11-proto/glproto
`--  x11-proto/dri2proto
`--  x11-proto/dri3proto
`--  x11-proto/xineramaproto

Note: apt and yum users need only run sudo apt-get build-dep xserver-xorg-video-ati and sudo yum-builddep xorg-x11-drv-ati respectively, to build the dependencies automagically. Arch users can install xf86-video-ati package to satisfy all dependencies, and portage users need only emerge the actual driver to fulfil all the dependencies.

Compiling

1. git clone git://anongit.freedesktop.org/xorg/driver/xf86-video-ati
2. cd xf86-video-ati
3. ./autogen.sh --prefix=/opt/xorg
4. make
5. sudo make install

Afterwards, edit:

/etc/X11/xorg.conf

Section "Files"
  ModulePath "/opt/xorg/lib/xorg/modules,/usr/lib/xorg/modules"
EndSection

Make sure you have these as well:

Section "Module"
  Load "dri"
  Load "dbe" # Double buffer extension // See compatibility on features page
  Load "glx" # OpenGL X protocol interface // See compatibility on features page
  Load "extmod" # Misc. required extension // See compatibility on features page
EndSection
    
Section "DRI"
  Group        "video"
  Mode         0666
EndSection

Then, edit:

/etc/X11/xorg.conf.d/20-radeon.conf

Section "Device"
  Identifier "radeonVGA"
  Driver "radeon"
  Option "AccelMethod" "Glamor" # See compatibility on features page
  Option "DRI3" "on" # Compatibility not very well documented, remove it if it fails
  Option "EnablePageFlip" "on"
EndSection

Feel free to run sudo chattr +i /etc/X11/xorg.conf to keep X from overwriting this (chattr -i will undo this).

Example xorg.conf: http://pastebin.com/raw/aE3e21Bn

IMPORTANT: Recompiling the driver will become a necessity after each major X upgrade (eg: 1.16 --> 1.17, not 1.16 --> 1.16.4), due to ABI changes.

Testing

To ensure DRI3 is enabled, run cat /var/log/Xorg.0.log | grep -i DRI3. Output should be as follows:

[    14.031] (**) RADEON(0): Option "DRI3" "on"
[    16.723] (**) RADEON(0): DRI3 enabled

External links

• For more info (eg: building libdrm and mesa from source, in this order)
• Real world benchmarks