Additional options for the radeon driver

2006-04-18T17:03:30Z

Marwatk: /* External Monitors */

Options for the radeon driver are documented on the radeon(4x) man page.

==External Monitors==
You can use '''MergedFB''' to provide dualhead '''Xinerama'''-like setups. MergedFB's pseudo-Xinerama is not Xorg server's Xinerama. You don't have to enable Xorg server's Xinerama to use MergedFB's pseudo-Xinerama. However, applications compiled with Xinerama support (Gentoo users USE="xinerama") can interpret pseudo-Xinerama hints, for example, to maximize to a single monitor instead of spanning two monitors.

The following (partial) '''Xorg''' config will make the Radeon card use '''1024x768''' on the internal lcd display and '''1280x1024''' on the external ('''Note''': only one screen/monitor section is needed (it controls the setup of the internal monitor) even though we have two displays):
'''N.B.:''' Modes used in the ''MetaModes'' also have to be present in the ''screen'' modes section.

Section "Device"
Identifier "ATI"
Driver "radeon"
'''# accelration'''
Option "AGPMode" "4"
Option "EnablePageFlip" "on"
Option "RenderAccel" "on"
'''# enable (partial) PowerPlay features'''
Option "DynamicClocks" "on"
'''# use bios hot keys on thinkpad (aka fn+f7)'''
Option "BIOSHotkeys" "on"
'''# enable radeon specific xinerama'''
Option "MergedFB" "true"
Option "CRT2Position" "RightOf"
Option "CRT2Hsync" "50-75"
Option "CRT2VRefresh" "30-82"
Option "MetaModes" "1024x768-1280x1024"
Option "MergedNonRectangular" "true"
BusID "PCI:1:0:0"
EndSection
Section "Monitor"
Identifier "InternalLCD"
Option "DPMS"
EndSection
Section "Screen"
Identifier "Default Screen"
Device "ATI"
Monitor "InternalLCD"
DefaultDepth 24
SubSection "Display"
Depth 24
Modes "1024x768"
EndSubSection
EndSection

Note: The '''CRT2''' directives always applies for the external monitore regardless of type (LCD, CRT...). The option '''MergedNonRectangular''' is needed to force the screens into two different sizes.

===External Monitors and Docking Stations/Port Replicators===
I seems that '''Xorg''' incorectly discovers the external displays when connected to a docking station/port replicator - the only solution to this problem (at least that I know of) is to start the laptop (and boot all the way into X) prior to inserting it in the dock.

It also happens that if you are attempting to use the mergedFB trick to
do dual head with out a docking station, you have to start X on the laptop
LCD first, then plug a monitor into the VGA port. If the external monitor
is already plugged in, the internal LCD will be blank.

===External Monitors and FireGL Boards with x.org 7===
x.org release 7, the modular release, broke mergedfb mode with FireGL boards (t4xp systems). Dual screen displays hard locked the machine in certain cases. This is fixed in x.org cvs. Fedora Core 5 (and possibly other distros using x.org 7) can get a new version of radeon_drv.so [http://www.marcuswatkins.net/firegl_xorg7_fedora.html here].

==AGP speed==

By default, the open source radeon driver forces 1x AGP speed. Quote from the developers:

tuning to the highest speed possible has caused hangs on some boxes, with no
discernable pattern, so we default to 'slow but safe' whilst giving the option
to go fast if the user wants to try it.

Higher speeds can be enabled by adding '''Option "AGPMode" "X"''' (where X is a number) in the '''Device''' section in {{path|/etc/X11/xorg.conf}}.

Section "Device"
Identifier "Videocard0"
Driver "radeon"
VendorName "IBM Thinkpad"
BoardName "ATIdd Mobility FireGL 7800"
'''Option "AGPMode" "4"'''
EndSection

With this option enabled (set to 4x speed), the X11 server should print ({{path|/var/log/Xorg.0.log}}):

(**) RADEON(0): Option "AGPMode" "4"
(**) RADEON(0): Using AGP 4x mode

==AGP Fast Writes==

By default, the open source radeon driver disables AGP Fast Writes. Fast Writes can be enabled by adding '''Option "AGPFastWrite" "yes"''' in the '''Device''' section in {{path|/etc/X11/xorg.conf}}.

Section "Device"
Identifier "Videocard0"
Driver "radeon"
VendorName "IBM Thinkpad"
BoardName "ATI Mobility FireGL 7800"
'''Option "AGPFastWrite" "yes"'''
EndSection

==Dynamic Clock scaling==

Please see:

*[[How to make use of Graphics Chips Power Management features]] <tt>(save even more battery power)</tt>
*[https://bugs.freedesktop.org/show_bug.cgi?id=2187 Xorg bug] <tt>DynamicClocks may hang your machine</tt>

==Color Tiling==

ColorTiling is supposed to be enabled by default. But, it looks like setting it explicitely to "on" increases the FPS in glxgears.

Option "ColorTiling" "on"

==Acceleration Architecture==

By default, the XAA architecture is used. EXA is newer and supposed to have better performance. It looks like it reduces the FPS in glxgears (maybe because it disables Page Flip) but makes the Composite extension be fast.

Option "AccelMethod" "EXA"

==Page Flip==

Page Flip increases performance but is not always supported. It will be disabled if the EXA architecture is used.

Option "EnablePageFlip" "on"

==Video overlay==

When the video overlay is used (e.g., by most video players) in dual-screen configuration, the content will be shown only on one head (LCD or CRT) and the other will display a blank rectangle. To control which head displays the video, use the following:

Option "OverlayOnCRTC2" "on"

To switch on the fly, use these commands:

:{{cmd|xvattr -a XV_SWITCHCRT -v 0|}}   (LCD)
:{{cmd|xvattr -a XV_SWITCHCRT -v 1|}}   (CRT)

{{HINT|You can configure [[acpid]] to execute these commands automatically when the lid is opened or closed.}}

== Related Links ==
*[http://www.x.org/X11R6.8.2/doc/radeon.4.html xorg 6.8.2 Radeon manual page]

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Additional options for the radeon driver