[CentOS] 4 monitors with one graphics card and standard driver

[m.roth at 5-cent.us]

Dale Dellutri wrote:
> On Tue, Apr 16, 2013 at 2:47 PM, <m.roth at 5-cent.us> wrote:
>
>> Dale Dellutri wrote:
>> > I've just test an ATI FirePro 2460 graphics card on CentOS 6.4.  It
>> > connects 4 monitors.
>> > It worked with the standard radeon driver.  I was able to arrange the
>> > monitors into my preferred configuration (as a square array, 1 upper
>> > left, 2 lower left, 3 lower right, 4 upper right) simply by clicking
>> > System -> Preferences -> Display, and then moving the
>> > four monitor images.  This creates the file ~/.config/monitors.xml .
>> <snip>
>> > I also tested two other cards: ATI FirePro 2450 and NVidia Quadro NVS
>> >420. For each of these cards, the BIOS shows the card in slot 1 as a
>> > PCI Bridge.lspci reports two identical video cards at 03:00.0 and
04:00.0.
>> > Though it's easy to set up two screens properly, xinerama would
>> > probably be required in an xorg.conf to get all four screens working
>> > properly.
>>
>> Would you mind sending me your xorg.conf offlist? I *may* have found
>> something in the one I've been handcrafting, but as my user is busy, I
>> won't be able to try it out for a while, and would love to see what you
>> did.
>
>> I'm still at the point of him having one monitor working fine, but the
>> other comes up, not mirrored, but unreachable by keyboard or mouse.
>> Looking at his old xorg.conf that worked with kmod-fglrx, and my own (an
>> NVidia card) I realized they only have one Screen sectiuon, and a
>> viewport on his (mine, of course, has twinview), so I've just edited his
>> that way.
>>
> I suggest that you restart the machine without X (in run level 3), then as
> root
> do:
>   # X -configure
> which will write a new xorg.conf.new in the current directory.

Tried that. It fails. Tried no xorg.conf, no X.
>
> But are you sure the problem is in the xorg.conf?  What does System ->
> Preferences -> Display show?

That's the fun one: it shows *one* monitor. I think I mentioned, xrandr
shows 1, also. It *also* describes it as DisplayPort-0, though it doesn't
like me using DisplayPort-0 for output, and I can't find what the output
name *is*. But if I say xrandr --screen 1, it shows me DisplayPort-1.

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