"Shatter" Might Finally Materialize For The X.Org Server

[phoronix]

Phoronix: "Shatter" Might Finally Materialize For The X.Org Server

The long-standing X.Org Server "Shatter" project might finally be revived by a student developer as an ultimate replacement to Xinerama...

http://www.phoronix.com/vr.php?view=MTcxODk

[computerquip]

Wouldn't it technically be replacing RandR 1.4 since that's what replaced Xinerama? I don't believe Xinerama is used often if at all...

I could totally be mistaken though.

[schmidtbag]

Wouldn't it technically be replacing RandR 1.4 since that's what replaced Xinerama? I don't believe Xinerama is used often if at all...

I could totally be mistaken though.

I think the catalyst drivers still uses it, and I think KDE supports it too.

[Ancurio]

Interesting. I've always been wondering how such multi GPU systems manage windows that are partly on both screens.

[Azpegath]

I think the catalyst drivers still uses it, and I think KDE supports it too.

Yes, I think so too.. When I switched back to the Catalyst driver (because I bought a 290, I'll be switching back when support for it is up and working) I had to re-enable Xinerama, if I'm not mistaken.

But another question: What does this mean? Sure, replace something broken with something not-so-broken, if that's the case. But does this automatically mean that? What if I only have one GPU, but several screen (which I think is the most common case for Xinerama), is it a use case for that as well? Will Shatter be a drop-in replacement, and will drivers that use Xinerama today automatically work with Shatter?

Edit: Hm, perhaps I was a bit quick to comment. I read "multiple GPUs", but his site says "multiple GPU screens". But the question regarding drop-in replacement is still valid!

[Gusar]

You guys need to be careful to differentiate between "xinerama the extension" and "xinerama the protocol".

Even xrandr uses the protocol. Its purpose is to inform clients - window managers, individual apps - about screen sizes and positions. Window managers use this info to do the right thing when you maximize a window (have it only cover the screen the app is running on, instead of maximizing it across all screens), for example. Another example, a panel/taskbar will use the info to position itself correctly (not position itself to be half on one screen, half on other).

The extension is something different, and while drivers still support it, I don't think anyone is still using it, except possibly in very specialized scenarios. The open drivers don't provide any 3D acceleration while the extension is in use. The nvidia blob does, but performance is diminished.

[Darksurf]

Does this mean simple OpenSource SLI/Crossfire will soon be a reality?

Just curious, but does this mean we could have OpenSource Crossfire/SLI when this is complete?

[s_j_newbury]

Just curious, but does this mean we could have OpenSource Crossfire/SLI when this is complete?

It's orthogonal to Crossfire/SLI. While Crossfile/SLI uses multiple GPUs to render to a single surface (which can be split over multiple screens), Shatter(/Xinerama) takes output from multiple GPUs to each to a a separate screen, which the Xserver can then combine into a single distributed desktop. Shatter has the advantage over Xinerama (the extension, not the protocol) that it is implemented at a protocol level which makes hardware acceleration possible.