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#1 2012-05-28 23:39:22

naquad
Member
Registered: 2010-02-27
Posts: 11

2 ATI video cards, one desktop, no Xinerama?

Hi.

I have 2 video cards (ATI Radeon HD 4870 and ATI Radeon HD 6750) operated by radeon free driver. Problem is I have to use Xinerama to utilize second video card which leads to whole bunch of problems:

  • no composite (hello 90-s!)

  • no double buffering (terminal emulators are blinking and the worst is conky blinking)

  • lots of issues with efficiency (everything is dead slow, no matter 2d/3d)

  • ... list continues ...

The question is: can I somehow utilize both video cards w/o Xinerama and second Xorg instance? Maybe I should try with Catalyst (aka fglrx propietary driver)?
Does anyone here has similar setup? Please help.

Thank you.

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#2 2012-05-29 06:52:20

Gusar
Member
Registered: 2009-08-25
Posts: 3,605

Re: 2 ATI video cards, one desktop, no Xinerama?

The only possibility is simply not using Xinerama. You get separate screens then (DISPLAY=:0.0, DISPLAY=:0.1, DISPLAY=:0.2, etc) and need to specifically say for each app on which screen it should start. You can't move apps between screens, but you can move the mouse.

Catalyst does have better Xinerama support, but there's still a performance penalty, and no compositing. Xinerama is simply outdated. Proper multi-GPU support is coming, but it'll probably take at least a few months before it's ready.

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#3 2012-05-29 09:22:35

naquad
Member
Registered: 2010-02-27
Posts: 11

Re: 2 ATI video cards, one desktop, no Xinerama?

Thank you for info. I still don't want to have two separate Xorg servers so I'll wait for better multi-GPU support. Could you please give me a link where I can track progress or at least some info on multi-GPU implementation?

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#4 2012-05-29 09:31:44

Gusar
Member
Registered: 2009-08-25
Posts: 3,605

Re: 2 ATI video cards, one desktop, no Xinerama?

There's Dave Airlie's blog (he's the one implementing all this): http://airlied.livejournal.com/, and then there's discussions of patches at the X mailing list: http://lists.x.org/archives/xorg-devel/ … hread.html. In particular this and this, but there's more.

Last edited by Gusar (2012-05-29 09:39:10)

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#5 2012-05-29 09:45:40

masteryod
Member
Registered: 2010-05-19
Posts: 433

Re: 2 ATI video cards, one desktop, no Xinerama?

naquad wrote:

I have 2 video cards (ATI Radeon HD 4870 and ATI Radeon HD 6750) operated by radeon free driver.

This sounds so so bad...

Sorry to stick my nose where it doesn't belong but what for do you need 2 GPUs under Linux? Multi-monitor setup will be easier on one card. You don't use binary drivers so GPGPU/OpenCL & CrossFire Gaming is pretty much out of the window too. Another thing is power consumption - 4870 is quite a beast in that matter and you've got two cards to feed. Even in idle - it's not negligible. For desktop (even full blown eye-candy with 3D effects/composition etc. on multiple displays) you don't need two powerful cards. If you dual boot with Windows (e.g. for gaming) it's still better to setup Linux desktop only on one of them. If you use only Linux get rid one of them (4870). You can also sell both and buy some low/middle range GeForce and install binary blob.

Last edited by masteryod (2012-05-29 09:49:34)

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#6 2012-05-29 10:52:44

naquad
Member
Registered: 2010-02-27
Posts: 11

Re: 2 ATI video cards, one desktop, no Xinerama?

masteryod wrote:

Multi-monitor setup will be easier on one card.

4 monitors.Not 2.

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#7 2012-05-29 12:13:35

Gusar
Member
Registered: 2009-08-25
Posts: 3,605

Re: 2 ATI video cards, one desktop, no Xinerama?

Wait, I just realized something...

Your 6750 supports four displays!! You don't need the other card. You don't even need Xinerama, xrandr will do the trick.

Edit: Wow, masteryod just had the same idea. Is that spooky, or what? smile

Last edited by Gusar (2012-05-29 12:17:13)

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#8 2012-05-29 12:15:41

masteryod
Member
Registered: 2010-05-19
Posts: 433

Re: 2 ATI video cards, one desktop, no Xinerama?

naquad wrote:
masteryod wrote:

Multi-monitor setup will be easier on one card.

4 monitors.Not 2.

Hmm right but look at "eyefinity" and "sapphire flex" radeon cards. Interesting, it should even work on open source drivers wow!

PS I suggest to read about the whole thing (linux support and displayport-dvi/hdmi/vga adapters if you don't have at least one DP display)

Gusar wrote:

Your 6750 supports four displays!! You don't need the other card. You don't even need Xinerama, xrandr will do the trick.

According to amd.com 6750 chip supports up to five displays, problem is: you need physical outputs build into your card and most of them are sold with only three outputs. I don't know if there is Y-splitter/dual-adapter possibility though.

Gusar wrote:

Edit: Wow, masteryod just had the same idea. Is that spooky, or what? smile

Haha indeed, I started to write answer before you post yours wink

Last edited by masteryod (2012-05-29 19:23:54)

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#9 2012-06-04 14:44:17

securitybreach
Member
From: In front of my computers
Registered: 2007-11-18
Posts: 416
Website

Re: 2 ATI video cards, one desktop, no Xinerama?

naquad wrote:

Hi.
The question is: can I somehow utilize both video cards w/o Xinerama and second Xorg instance? Maybe I should try with Catalyst (aka fglrx propietary driver)?
Does anyone here has similar setup? Please help.

Thank you.

It took me two weeks to figure it out but I have my machine setup with dual Radeon cards and 4 monitors with the fourth monitor as a Separate X  session:

https://bbs.archlinux.org/viewtopic.php … 5#p1110065

If there is anything you need to look or anything to help you out, just let me know.

Thanks

Last edited by securitybreach (2012-06-04 14:44:40)


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