Arch Linux

lykwydchykyn

Member

Registered: 2013-07-11

Posts: 91

Struggling to enable 3rd display with a second card

I have a Dell Optiplex 3020 with onboard intel graphics.  It has a feature called "Multi-Display" which is supposed to allow you to run a PCIE graphics card in addition to the onboard.  To that end, I've installed and connected a monitor to an AMD Radio HD 5430.

My coworker has the exact same hardware running with Ubuntu.  It works out-of-the-box with three monitors (Two using the onboard intel, one using the VGA port on the AMD).

I can't get it working on Arch.

Without any xorg.conf files, the Intel-connected monitors come on, but the AMD stays dark.

I've cobbled together some conf files by studying the output of "X -configure" on an ubuntu live disc, and managed to get the AMD display to show an empty Xsession (no window manager, etc) apparently running on DISPLAY=:0.1.  I can launch things on it by manually specifying the DISPLAY, but my window manager (awesome) doesn't extend to it and it will not receive mouse or keyboard.

My xorg configuration looks like this:

Section "ServerLayout"
	Identifier "Custom monitor config"
	Screen	   0	   "Screen0" 0 0
	Screen	   1	   "Screen1" RightOf "Screen0"
	Screen 	   2	   "Screen2" RightOf "Screen1"
EndSection


Section "Monitor"
	Identifier "VGA1"
	Option "Primary" "true"
EndSection

Section "Monitor"
	Identifier "DP1"
	Option "RightOf" "VGA1"
EndSection

Section "Monitor"
	Identifier "VGA-1-1"
	Option "RightOf" "DP1"
EndSection


Section "Screen"
	Identifier "Screen0"
	Device "Card0"
	Monitor "VGA1"
EndSection

Section "Screen"
	Identifier "Screen1"
	Device "Card0"
	Monitor "DP1"
EndSection

Section "Screen"
	Identifier "Screen2"
	Device "Card1"
	Monitor "VGA-1-1"
EndSection
Section "Device"
	Identifier "Card0"
	Driver "intel"
	BusID "PCI:0:2:0"
EndSection

Section "Device"
	Identifier "Card1"
	Driver "radeon"
	BusID "PCI:1:0:0"
EndSection

Basically, I just want to get that third screen (the one on the AMD) into DISPLAY=:0 with the Intels so I can use it.

lykwydchykyn

Member

Registered: 2013-07-11

Posts: 91

Re: Struggling to enable 3rd display with a second card

Ok, I sorta solved this one.

I ditched the xorg configs altogether, then added a script to /etc/xinit/xinit.rc.d/ that looks like:

xrandr --setprovideroutputsource 1 0
xrandr --output VGA1 --primary
xrandr --output DP1 --right-of VGA1
xrandr --output VGA-1-1 --auto --right-of DP1

That works, although the perfectionist in me wishes I could put this in the xorg.conf so the display manager gets these settings too.  I couldn't find the equivalent of "setprovideroutputsource" for xorg.conf, though.

No biggie, though, I'm too busy basking in the glory of three full monitors of Emacs buffers. :-)

Last edited by lykwydchykyn (2015-10-01 22:57:10)

lykwydchykyn

Member

Registered: 2013-07-11

Posts: 91

Re: Struggling to enable 3rd display with a second card

Alas, not out of the woods yet.

It appears that my emacs buffers are getting garbled whenever I scroll.  I've spent the last two days wrestling with this but emacs is not really usable with this configuration.

I *think* that disabling SNA on the intel chip should help, it seems to fix it when I do so.

The problem is that the only way I can disable SNA is to create an xorg.conf file (or fragment), and the moment I do that I lose my AMD screen.  xrander no longer sees the provider.

I've spent some hours fiddling with xorg.conf files, trying to reproduce the three-monitor setup in various ways.  I got close with Xinerama, but nothing seems to get it like I have it with just the xrandr commands.

I need to find out either:

1. How to reproduce my three-screen setup in xorg.conf.
2. OR, how to disable SNA and revert to UXA without using xorg.conf.

any help?