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DeviousOne

Member

Registered: 2015-11-11

Posts: 1

xrandr with multiple ATI Video cards, only one works at a time.

I have two ATI 7950's and am attempting to use two monitors, one off each card, both using DVI connections.  I'm using the open drivers, and really don't want to change that.

Both cards are recognized by the system.

 lspci | grep VGA
02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti PRO [Radeon HD 7950/8950 OEM / R9 280]
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti PRO [Radeon HD 7950/8950 OEM / R9 280]

$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0xb4 cap: 0x2, Sink Output crtcs: 6 outputs: 4 associated providers: 0 name:modesetting
Provider 1: id: 0x49 cap: 0x2, Sink Output crtcs: 6 outputs: 4 associated providers: 0 name:modesetting

However xrandr only shows one monitor.

$ xrandr 
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 477mm x 268mm
   1920x1080     60.00*+
   1680x1050     59.88  
   1400x1050     74.76    59.98  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1152x864      75.00  
   1024x768      60.04    75.08    75.03    70.07    60.00  
   960x720       75.00    60.00  
   928x696       75.00    60.05  
   896x672       75.05    60.01  
   832x624       74.55  
   800x600       75.00    70.00    65.00    60.00    72.19    75.00    60.32    56.25  
   700x525       74.76    59.98  
   640x512       75.02    60.02  
   640x480       60.00    75.00    72.81    75.00    60.00    59.94  
   720x400       70.08  
   576x432       75.00  
   512x384       75.03    70.07    60.00  
   416x312       74.66  
   400x300       72.19    75.12    60.32    56.34  
   320x240       72.81    75.00    60.05  

My current x config is

$ cat /etc/X11/xorg.conf.d/05-radeon.conf 
Section "Device"
	Identifier	"Device0"
	VendorName	"ATI"
	Option "monitor-VGA-1"	"VGA"
    	Option "monitor-DVI-0"	"DVI"
	Option "ZapoHeads"	"DVI-0"
	BusID		"PCI:2:0:0"
EndSection

Section	"Device"
	Identifier	"Device1"
	Option "monitor-VGA-1"	"VGA"
	Option "monitor-DVI-0"	"DVI"
	Option "ZapoHeads"	"DVI-1"
	VendorName	"ATI"
	BusID		"PCI:3:0:0"
EndSection

I've tried using DVI-0 for Device1, but x won't load at all when set that way.

If I remove either selection it will work and alternate displays, but not both at the same time.

Any help would be greatly appreciated, I feel I've ran the limit of my understanding of the issue. The only thing close I've found is on this page. There doesn't seem to be any resolution, or the user never commented on what made it work.

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 14,840

Re: xrandr with multiple ATI Video cards, only one works at a time.

Option "ZapoHeads"	"DVI-1"

That option is specific to the radeon driver, but xrandr --listproviders gives modesetting as the driver in use.
If you look at Xorg.0.log , you'll prob see an error / warning about ZapoHeads .

Verify you havexf86-video-ati installed.

Also add a

Driver         "radeon"

line to both your device sections,so X is forced to use the radeon driver.

---

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