RDP (remote desktop) backend

[ddevault]

• Spin up FreeRDP server
• Allocate headless outputs for each peer
• Send frame updates to clients via RFX
• Send frame updates to clients via NSC
• Send raw frame updates for clients which support neither
• Keyboard input
• Pointer input
• Clean up

[emersion]

Would be nice to let the compositor allocate the output, so that it can decide to either create a headless one or use an existing one. That would also remove all the OpenGL stuff from the backend.

[ddevault]

Hmm, maybe. The way I saw this working out is that the compositor would mirror to the RDP outputs if they wanted to use an existing one. I also like that this lets you transparently add RDP support without any changes to the compositors.

[emersion]

Still unsure whether this should be merged or not. A client with virtual-keyboard + virtual-pointer + virtual-output would probably be better.

[ddevault]

I'm starting to wonder if it wouldn't be nice to have both.

[emersion]

In any case, you could use a headless backend inside the RDP backend to avoid having to re-implement wlr_output.

I still think the compositor should be able to customize the output if needed, this could be optional. This can be useful for mirroring or remote controlling.

[ddevault]

That seems like a nice to have for a future patch.

[emersion]

Note: this backend is better than Weston's because it uses OpenGL (the Weston backend forces the software renderer).

[ddevault]

Or it would be if this didn't force llvmpipe for some reason <_< headless backend has the same problem. No luck figuring it out yet.

[progandy]

@ddevault Maybe open a render node fd (/dev/dri/render...) and create a normal GBM backed mesa platform just without any crtcs or outputs? My very shallow reading of surfaceless mesa seems to indicate that it is built on top of llvmpipe.

[ddevault]

Maybe? I'm not sure how that works to be honest. Interested in trying a patch?

[emersion]

Maybe open a render node fd (/dev/dri/render...) and create a normal GBM backed mesa platform just without any crtcs or outputs?

That's how the not-yet-merged Weston patch works: https://lists.freedesktop.org/archives/wayland-devel/2017-July/034423.html

[emersion]

I'd first try to read the mesa code though.

[progandy]

Maybe? I'm not sure how that works to be honest. Interested in trying a patch?

Currently not really. I don't really know how that works either. I just remembered reading about render nodes for unprivileged gpu access without a DRM master for computation and DRI_PRIME.

I found this implementation in virgl: https://gitlab.collabora.com/virgl-es/virglrenderer/blob/master/src/virgl_egl_context.c

#1114 is probably related. A single DRM backend could be designed that supports physical and virtual outputs if it is run as DRM master. If it is started on a render node, it will only have virtual outputs and be completely headless.

[emersion]

Other idea: use EGL_PLATFORM_DEVICE_EXT. I might try this this weekend.

[ascent12]

use EGL_PLATFORM_DEVICE_EXT

Mesa does not support this.

[emersion]

On my machine EGL_PLATFORM_SURFACELESS_MESA correctly selects i915 and doesn't fallback to software rendering. Maybe this is a Mesa bug?

Can you try with export EGL_LOG_LEVEL=debug, just to make sure we're not missing anything?

[progandy]

I walked through the code and it look like surfaceless does try to create a render node: https://gitlab.freedesktop.org/mesa/mesa/blob/master/src/egl/drivers/dri2/platform_surfaceless.c#L358

• first try: render node and hardware rendering
• second try: DRM master with software rendering
• last try: swrast without DRM

I did a log as well, looks like r600 is loaded.

EGL_LOG_LEVEL=debug WLR_RDP_TLS_CERT_PATH="$PWD/cert/cert.pem" WLR_RDP_TLS_KEY_PATH="$PWD/cert/key.pem" WLR_BACKENDS=rdp ./rootston 2>rootston-rdp.log

rootston-rdp.log (rootston 0.4-9-g71abbdfd)

[ddevault]

This is ready for review. It still ends up using llvmpipe on my system, but that can be solved separately.

[ddevault]

Addressed @emersion's comments and rebased into a single (changelog-ready) commit.

[emersion]

Thanks!

[RorraVox]

Can someone explain in simple words how start freerpd with sway? I use remmina i think should be compatible.
I cant find nothing about that...
Thank you.

[twhitehead]

The original patch put a bunch of info into docs/env_vars.md. Looks like it was dropped in ebdbe17 in favour of wayvnc though.