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HappyTetrahedron

Member

Registered: 2016-06-09

Posts: 2

Three monitors with hybrid graphics card: full resolution not working

Hello everybody

I have an HP pavilion dv7 and am trying to set up three monitors (the integrated monitor plus two external ones).

These are my graphic cards:

lspci | grep VGA
01:05.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RS880M [Mobility Radeon HD 4225/4250]
02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Madison [Mobility Radeon HD 5650/5750 / 6530M/6550M]

I'm using the radeon driver. It seems to be the only driver that works with these cards.
So far, I have been using my dedicated card; the integrated card was disabled.

When I try to enable the second monitor with xrandr I get:

xrandr --output VGA-1 --auto --left-of LVDS-1
xrandr: Configure crtc 2 failed

To my understanding, this means that my graphics card can't handle that monitor. I can enable it if I use a lower resolution on either monitor, so I suppose the dedicated card is simply too weak.

Now, I do have two graphics cards, so I thought it might be possible to use all monitors at full resolution by using both cards. Xrandr does recognize both cards as providers:

xrandr --listproviders
Providers: number : 2
Provider 0: id: 0xa5 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 3 associated providers: 1 name:ATI Mobility Radeon HD 5000 Series @ pci:0000:02:00.0
Provider 1: id: 0x53 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 2 outputs: 2 associated providers: 1 name:ATI Mobility Radeon HD 4200 @ pci:0000:01:05.0

So I did the following:

xrandr --setprovideroutputsource 1 0
xrandr --output VGA-1-0 --auto --left-of LVDS-1

The VGA output is apparently connected to both graphics cards. I was trying to access the screen attached via VGA using the integrated graphics card. And this seemingly worked; xrandr reported the new screen as connected and I was actually able to move the mouse over the left border of the LVDS-1 screen, so there seemed to be another screen--except the monitor attached to the VGA port reports no signal.

I think I am making some mistake here, maybe I misunderstood something. I'd be glad if anyone could help me find the problem, or maybe point to an alternative solution for using all three monitors at full resolution.

Some more information on how the outputs are connected to the cards:

* When I use the integrated card, the VGA output shows up as VGA-0 and the internal monitor shows up as LVDS-0. The HDMI output doesn't show up.
* When I use the dedicated card, the VGA output is VGA-1, the internal one is LVDS-1 and the HDMI output is HDMI-0.

I suppose this means that the VGA and internal outputs are wired to both cards somehow, while the HDMI output is wired to the dedicated card only.

Thanks in advance for any help, I really appreciate it. Please let me know if I need to provide more information.

edit: I got some more information.

Previously I've been using no Xorg.conf, but now I've set one up that leads to the same results I described above. You can find it here:
http://pastebin.com/bDxrqRqN

It has two screens configured, but when I run xrandr, I only see one screen (Screen 0).
Also, the integrated card uses the modesetting driver - if I change that to radeon, the integrated card doesn't even show up as a provider in xrandr.

Also, here's my Xorg.0.log from a running session using the above config:
http://pastebin.com/ZZ3vVRLu

Last edited by HappyTetrahedron (2017-01-03 11:57:07)