Help? Xinerama with two cards

[Alex Deucher]

On Fri, Jul 12, 2013 at 1:04 AM, David Iannucci
<kbetzy at punchcutter.ml1.net> wrote:
> Thanks for the responses Felix and Dave.  I will rearrange the
> quotations below a bit:
>
>> I find config files easier to work with than xrandr. You might
>> want to try. My last dual head session with Intel and Radeon left
>> these behind:
>
> Thanks... checked these out. I took your advice and did my best to
> craft an xorg.conf based on your examples and other documentation I
> found, but nothing is happening on my second monitor (this doesn't
> surprise me much).
>
> I have read a few times now that Xorg is not supposed to need config
> files any more - that it's mostly self-configuring, and xrandr is the
> way to go to manipulate your display if you need to, and this appeals to
> me a lot..... I never was very comfortable with xorg.conf :-)
>
> Please recall that what I'm trying to do is drive two heads off of
> _two different_ GPUs. I was told a few years ago by someone who
> seemed to know what he was talking about that X just doesn't DO that
> (at the time). My understanding was that recent changes in xrandr 1.4
> would allow it.
>
>> KDE 4.11 has KScreen, which is supposed to provide easy management of
>> multi screen configuration.
>
> Trying to go more minimalist, not more bloatist :-) :-)
>
> So here's the nutshell of what I'm left with:
>
> Xrandr shows me 3 outputs: VGA1, HDMI2, and DP1 (with only VGA1
> "connected", even though 2nd monitor is plugged into DVI port of
> Radeon). This DP1 original fooled me into thinking that the 2nd port on
> my Radeon card was a DisplayPort, but close examination shows it to be
> HDMI. So "DP1" is confusing. Between the 2 GPUs there are 4 output ports
> (two on each), so the fact that xrandr shows me 3 is a hint that my
> kernel is.... ok? But why not four?
>
> Finally, perhaps I failed to mention before that sometimes partial
> chunks of output (system boot messages), or a "distortion pattern" (?)
> appear on monitor 2. This is encouraging to me, but I don't know if it's
> really good news.
>
> Anyone who missed my original post can look below to see that
> xrandr --listproviders gives a sensible output.
>
> Hoping that this, my last post on the topic before giving up and
> probably buying an HDMI-VGA adaptor, will attract the attention of
> someone who knows how to troubleshoot it.
>
> At the very least, I would really like to know the truth about
> (1) whether X.org has never, historically, been able to drive a
> dual-head setup off of two GPUs, and

X has been able to drive multiple GPUs for years via a static xorg.conf.

>(2) whether xrandr 1.4 is really
> supposed to remedy this. Thanks a lot.
>

It's a start, but it's still not there for all configurations.  The
provider stuff in xserver 1.14 was mainly focused on support for
hybrid laptops and hot-pluggable USB display adapters.

Alex

> Dave
>
>
>
> On Tue, Jul 2, 2013, at 13:52, Felix Miata wrote:
>> On 2013-07-02 13:21 (GMT-1000) David Iannucci composed:
>>
>> > David Iannucci wrote:
>>
>> >> I'm trying to set up a xinerama arrangement over two graphics cards
>> >> (Intel + Radeon), taking advantage of xrandr 1.4's features which
>> >> (I understand, perhaps mistakenly, to) support this configuration.
>> >> I'm running xorg server 1.13.4 on Gentoo. It might be useful for
>> >> you to know in addition that I'm running a barebones KDE 3.5.10
>> >> desktop on it.
>>
>> >> If I do --listproviders, I get both cards listed:
>>
>> >> # xrandr --listproviders
>> >> Providers: number : 2
>> >> Provider 0: id: 0x87 cap: 0xb, Source Output, Sink Output, Sink
>> >> Offload crtcs: 3 outputs: 3 associated providers: 0 name:Intel
>> >> Provider 1: id: 0x57 cap: 0xd, Source Output, Source Offload, Sink
>> >> Offload crtcs: 6 outputs: 2 associated providers: 0 name:radeon
>>
>> >> However no use of --setprovideroutputsource or
>> >> --setprovideroffloadsink (with arguments "0 1" or "1 0") will do
>> >> what I want.  Am I completely misunderstanding this?
>>
>> >> One monitor is connected to VGA output of integrated Intel GPU, and
>> >> the other to DVI output of Radeon (HD 7570) PCI card.  I think kernel
>> >> stuff is set up properly:
>>
>> >> # lsmod | grep radeon
>> >> radeon                858404  1
>> >> cfbfillrect             3714  2 i915,radeon
>> >> cfbimgblt               2039  2 i915,radeon
>> >> ttm                    58739  1 radeon
>> >> cfbcopyarea             3350  2 i915,radeon
>> >> drm_kms_helper         26569  2 i915,radeon
>> >> fb                     33637  6
>> >> i915,fbcon,drm_kms_helper,radeon,softcursor,bitblit
>> >> backlight               4248  2 video,radeon
>>
>> >> Please document this functionality more clearly! Any help with this
>> >> will be much appreciated. I can try to end-run the problem by asking
>> >> my boss to buy me an HDMI-capable monitor, to plug into the second
>> >> port of Intel card, but I've already got the Radeon, and I'd rather
>> >> try to figure this out before throwing money at it :-) Thx.
>>
>> > So.... I've left this sit for a while and it doesn't look like there's
>> > anyone here able to help.
>>
>> > Is there a better place to ask for help with xrandr? Have I left out
>> > some crucial information?
>>
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