xf86-video-modesetting X.Org Driver Sees Patch For "TearFree" Page Flipping

[phoronix]

Phoronix: xf86-video-modesetting X.Org Driver Sees Patch For "TearFree" Page Flipping

While several X.Org DDX drivers in the past have implemented a "TearFree" xorg.conf driver option to try to eliminate screen tearing when running an X.Org Server without a composited environment, the xf86-video-modesetting generic DDX that is widely used has lacked that option. That is until a developer finally stepped up and has pending support for the "TearFree" option...

https://www.phoronix.com/news/xf86-video-modesetting-TearFree

[tildearrow]

Yay! Does this mean the other DDX drivers will be deprecated soon?

[ehansin]

I get so confused on video driver stuff, but have slowly been putting the pieces together. May be a good place for these related questions:

If I am running a newer (say 8th Gen iCore) Intel processor using the iGPU, would it make more sense to use "xf86-video-modesetting" or "xf86-video-intel" driver these days?

On a related note, if I am running a Wayland compositor, I think I know that the compositor itself doesn't need these "xf86-video-X" drivers. But if an app requires XWayland to be fired up, does XWayland need one of these to work?

Thanks as always!

[rene]

I get so confused on video driver stuff, but have slowly been putting the pieces together. May be a good place for these related questions:

If I am running a newer (say 8th Gen iCore) Intel processor using the iGPU, would it make more sense to use "xf86-video-modesetting" or "xf86-video-intel" driver these days?

On a related note, if I am running a Wayland compositor, I think I know that the compositor itself doesn't need these "xf86-video-X" drivers. But if an app requires XWayland to be fired up, does XWayland need one of these to work?

Thanks as always!

I often found xf86-video-intel more full featured and to perform better. If you run Wayland, Xwayland will use none of this drivers, and instead everything is rendered thru Wayland.

[bug77]

Somewhat ironic, but shortly after Wayland gets tearing, this X driver gets rid of it.

[ehansin]

I often found xf86-video-intel more full featured and to perform better. If you run Wayland, Xwayland will use none of this drivers, and instead everything is rendered thru Wayland.

Hi Rene. Thanks for the heads up and clarification. Going forward, I intend to try and stick to Wayland compositors, leveraging Xwayland where it is required. Sounds like this sort of becomes a "non-issue" for me at that point Thanks again!

[treba]

I get so confused on video driver stuff, but have slowly been putting the pieces together. May be a good place for these related questions:

If I am running a newer (say 8th Gen iCore) Intel processor using the iGPU, would it make more sense to use "xf86-video-modesetting" or "xf86-video-intel" driver these days?

On a related note, if I am running a Wayland compositor, I think I know that the compositor itself doesn't need these "xf86-video-X" drivers. But if an app requires XWayland to be fired up, does XWayland need one of these to work?

Thanks as always!

Modesetting and Xwayland both use GLAMOR, which is a GL implementation of the X11 2D drawing APIs. GLAMOR can be used on top of any sufficiently modern GL implementation, including Zink (i.e. on top of Vulkan). Older hardware had dedicated 2D engines for that which thus needed dedicated drivers - that's what xf86-video-intel is for.
There are few applications these days which still use and actually benefit from those 2D APIs and at the same time the dedicated drivers are more complex and see very little maintenance. So if you use the Intel driver instead of modesetting (or Xwayland), what you can generally expect is slightly better performance in selected 2D workloads on older hardware - and way more bugs.
With Tearfree now working on the modesetting driver IMO there shouldn't be many, if any, reasons left to prefer xf86-video-intel. And by the way, Firefox blocklists hardware acceleration when detecting the later, because it causes so many issues.

[Unklejoe]

How does this work in relation to “xpresent”? I’m using Ubuntu MATE 22.04 on a Tiger Lake Intel machine and I have no tearing because the compositor (Marco) uses xpresent by default.

Is this tear free option another way of accomplishing the same thing?

[binarybanana]

Crazy how distros have been pushing for modesetting without this. TearFree is the only way to get a tear-free desktop in multionitor setups or when rotation is used. I'm convinced this decision has done a lot of damage to Xorg's reputation.

Older hardware had dedicated 2D engines for that which thus needed dedicated drivers - that's what xf86-video-intel is for.

It's not just old hardware. The 2D engine on Intel GPUs has only gotten faster and more powerful over time. On Xorg it's used to accelerate XRender operations which are often used for things like font rendering/drawing and compositing. Even their dGPUs still have powerful 2D hardware. It can do stuff like blitting, alpha blending, scaling, rotation and other stuff. This is obviously useful for modern desktops. It's a tragedy this is being abandoned on the Linux desktop.

[treba]

Crazy how distros have been pushing for modesetting without this. TearFree is the only way to get a tear-free desktop in multionitor setups or when rotation is used. I'm convinced this decision has done a lot of damage to Xorg's reputation.

The quality of these drivers has been pretty bad AFAICS, tearing being a lesser problem. So I'd disagree on this.

It's not just old hardware. The 2D engine on Intel GPUs has only gotten faster and more powerful over time. On Xorg it's used to accelerate XRender operations which are often used for things like font rendering/drawing and compositing. Even their dGPUs still have powerful 2D hardware. It can do stuff like blitting, alpha blending, scaling, rotation and other stuff. This is obviously useful for modern desktops. It's a tragedy this is being abandoned on the Linux desktop.

The later features to me sound like those of the display hardware - overlay planes etc. where you can offload e.g. more parts of video playback to the hardware, including YUV->RGB conversion. These features do get used more and more on Wayland, which was designed to meet requirements of modern hardware. (Edit: Staying on X11 means to lose out on them, which indeed is a tragedy :P )

Regarding XRender - that has been deprecated long ago in most modern apps, toolkits and compositors. In the embedded world, where performance is most crucial, apps usually use Wayland (or KMS/DRM APIs directly) these days.