Exporting framebuffer apps on other displays.

[Linux-SWAT]

Hi !

X has great network export capabilities, using things like xhost.

I now wonder if i can export applications displays like picodrive or starcraft to another computer (non-OP).

 

[_wb_]

ssh -X ? Or what do you mean?

 

[TrashyMG]

I think he's talking about applications that directly write to the framebuffer.

 

[_wb_]

Oh right. I would assume that to be hard, since the point of writing directly to a framebuffer is that it's more direct and thus faster than having the overhead of X, but that also means that there's no intermediate thing that can act as a forwarding mechanism, you're just writing to memory. I guess the only way to do it is to have some kind of screen capture application read the framebuffer and send it over the network at some framerate -- but there would be no guarantee that it catches all frames, it would be wasteful for static images, and synchronization may be an issue. Also it would be quite CPU and memory intensive, so it would probably slow down the system significantly. I don't know if such a thing already exists.

 

[levi]

I wonder if it's possible in hardware. How does the TV out circuitry grab the scaler layer and rescale it for SD resolutions?

 

[Exophase]

Oh right. I would assume that to be hard, since the point of writing directly to a framebuffer is that it's more direct and thus faster than having the overhead of X, but that also means that there's no intermediate thing that can act as a forwarding mechanism, you're just writing to memory. I guess the only way to do it is to have some kind of screen capture application read the framebuffer and send it over the network at some framerate -- but there would be no guarantee that it catches all frames, it would be wasteful for static images, and synchronization may be an issue. Also it would be quite CPU and memory intensive, so it would probably slow down the system significantly. I don't know if such a thing already exists.

If you could somehow hook the fbdev syscalls you could perform updates around screen flips. I don't think anyone is blindly writing to the framebuffer with zero synchronization mechanism in place.

Some kind of pass-through fbdev device might be the route to attempt this.