X.Org Server Adds "AsyncFlipSecondaries" To Deal With Crappy Multi-Monitor Experience

[blacknova]

Stupid and off-topic question, but I always wondered what's the use case for clone mode. It specifically annoys me not understanding it because it's the default pretty much everywhere (not just X or Wayland, but Mac and Windows) and I see no use for it.

Simple really, it is used if you want to share you screen to larger display i.e. for presentation.

[brad0]

Xorg fanboys: See we are not dead
Most Linux users: someone still works on Xorg?

Linux users always showing how ignorant they are.

[sinepgib]

Not on clone mode.

Stupid and off-topic question, but I always wondered what's the use case for clone mode. It specifically annoys me not understanding it because it's the default pretty much everywhere (not just X or Wayland, but Mac and Windows) and I see no use for it.

[whitecat]

Exactly, that's what I thought. So basically whitecat is talking nonsense.

Nobody cares if Wayland is technically able to do that or not.
The fact is that the end-user cannot set it up with the GNOME or KDE screen manager because there is no such option...

[furtadopires]

Some say every reality can be expressed by the digits of pi. It's clear it can also be expressed with the names of bands.

And Jojo references

[sinepgib]

I get your pessimism but strangers on the internet are the best people on Earth. One can only describe them as a mix of MLK, Einstein, Confucius and Aristotle.

Some say every reality can be expressed by the digits of pi. It's clear it can also be expressed with the names of bands.
You gave me a good laugh, thanks.

[tomas]

There's no reason why a Wayland compositor can't drive separate monitors at different refresh rates (without tearing), no matter if they show the same or different contents.

This change is a workaround for an architectural limitation of Xorg (single framebuffer which spans all outputs).

Exactly, that's what I thought. So basically whitecat is talking nonsense.

[MrCooper]

And assuming you are correct, is that a limitation of Wayland itself or just in a specific compositor like Mutter, Sway or Kwin?
Do all of the above compositors have this problem you claim and can it then be derived to be a design problem in the Wayland protocol itself?

There's no reason why a Wayland compositor can't drive separate monitors at different refresh rates (without tearing), no matter if they show the same or different contents.

This change is a workaround for an architectural limitation of Xorg (single framebuffer which spans all outputs).

[tomas]

Not on clone mode.

And assuming you are correct, is that a limitation of Wayland itself or just in a specific compositor like Mutter, Sway or Kwin?
Do all of the above compositors have this problem you claim and can it then be derived to be a design problem in the Wayland protocol itself?

[caligula]

On Wayland you can have multiple screens at different refresh rates, each of them having fullscreen or non-fullscreen "unredirected"/direct scanout clients. Without tearing. In other words a no compromise situation. I think atm only Weston is already capable of doing such a extreme situation (especially the non-fullscreen direct scanout case, which requires overlay plane support via atomic KMS). But a typical situation like screen A 144Hz with a unredirected game + screen B 60Hz + screen C 60Hz works just fine without tearing on Gnome - and if I'm not mistaken on Sway and KDE as well.
That's possible because unlike on X11 there's no "global" VSync on Wayland. Clients receive frame callbacks (or/and presentation times) for the screens they are visible on. Clients on different screens don't need to be in sync.

Apparently X can also fail in other ways. I previously had a problem with Nouveau with two 59,95 and 60 Hz monitors. One of the screen was showing a bright flash every N frames when there was a missing non-fractional frame every 60 frames or so. A pal who claims he's more familiar with Linux said that I'm just idiot and can't configure my system like normal users. Linux simply cannot fail like that. Gotta love these experts.