Automatic headless outputs

[any1]

This automatically creates a headless output instead of relying on NOOP-1.

Headless outputs can be resized, so this will allow VNC clients to set arbitrary modes on the output.

The auto-headless plugin will need to be added to the relevant configuration files and the wayfire-pi script needs to be modified to enable the headless outputs. Mine looks like this:

#!/bin/sh

. /usr/bin/setup_env

export QT_WAYLAND_DISABLE_WINDOWDECORATION=1
export DESKTOP_SESSION=LXDE-pi-wayfire
export WLR_XWAYLAND=/usr/bin/xwayland-xauth
export XAUTHORITY=~/.Xauthority
export WLR_BACKENDS="drm,headless"
export WLR_HEADLESS_OUTPUTS=0

if [ -f "$HOME/.config/gtk-3.0/gtk.css" ] ; then
  rm "$HOME/.config/gtk-3.0/gtk.css"
  sync
fi

if raspi-config nonint gpu_has_mmu ; then
  exec /usr/bin/wayfire $@
else
  exec /usr/bin/wayfire -p $@
fi

[spl237]

Just tried merging this. It all built fine, but even without the changes to wayfire.ini and wayfire-pi, I am still getting a valid output when headless. My understanding based on the above is that that should not happen?

[any1]

I am not sure what you mean by "valid output".

Before these changes, you should see "NOOP-1" when there is no output connected. After the change, you should see "HEADLESS-N" where N is a positive integer. When there is an output connected you should not see either of "NOOP-1" or "HEADLESS-N".

There are two separate protocols for enumerating outputs. One is the core object registry and the other is wlr-output-management-v1. The former will always show you all physical and virtual outputs including the noop, but the latter excludes the noop.

For enumerating wl_output from the registry, one can call: wayland-info -i wl_output

For enumerating output-management outputs, one can call wlr-randr

[spl237]

I was expecting that the new changes would mean that I would only get an output when headless if I made the corresponding changes to the config to enable the new behaviour. But from what you say above, I assume that I am getting the NOOP output when I haven’t made the changes, and will get the new HEADLESS output if I do make the config changes?

[any1]

But from what you say above, I assume that I am getting the NOOP output when I haven’t made the changes, and will get the new HEADLESS output if I do make the config changes?

Yes, that appears to be the most likely outcome, but this can be tested by calling wlr-randr in the two different scenarios.

[spl237]

This doesn't seem to be working all that well for me.

Without the auto-headless plugin and those environment variables, I get the same behaviour as before.

With those changes, I can indeed see a display labelled as HEADLESS-2 in wlr-randr. But a lot of other things seem to be broken:

• Booting with no HDMI display connected boots to greeter rather than desktop. If I then log in at the greeter, the desktop starts briefly; then enlarges to a larger screen size, before clearing to a grey window rather than the desktop, and then dropping back to the greeter again. I can't actually get to a usable desktop.
• Booting with an HDMI display connected gives a desktop on the local display, but the mouse and keyboard are unresponsive. Logging in via VNC while in this state gives a workable mouse and keyboard in the VNC session, but not on the local seat. If I disconnect the HDMI display at this point, this is when I can see the HEADLESS-2 display in wlr-randr, but I cannot use the local seat at all - if I reconnect the HDMI, the display works, but local mouse and keyboard do not.

[any1]

Looks like this needs more work.

[any1]

I'm taking a different approach to this now being that things are somewhat fragile w.r.t. outputs coming and going. Now the NOOP output is just resizeable. I also fixed a potential crash due to uninitialised pointer.

Edit: I should also mention that config changes and changes to the script are no longer required, nor will they do any good.

[spl237]

OK, this now means that I can see the HEADLESS-2 output in wlr-randr, which is good. You say it is resizeable, but the only mode offered by wlr-randr is 1920x1080, and if I try to force it to another size, I get told that the size requested is an "unknown mode". I can set the orientation to inverted, and that seems to work, so the output is responding to wlr-randr - it just cannot be resized with it.

Edit - which may, of course, be a wlr-randr problem?

Edit2 - ah, need to use the "custom-mode" option in wlr-randr, not "mode"! That works fine.

[any1]

You shouldn't be seeing HEADLESS-2. This is a completely different approach where instead of creating headless outputs, the NOOP-1 output is now resizeable.

I force pushed the changes. Did you pull fail?

[spl237]

Hmm. OK, I am now seeing the NOOP-1 output, and it is resizeable. Not sure why I was still seeing the HEADLESS-2 output when I tried earlier - I might have forgotten to reboot. But it all seems to work fine for me now.

[spl237]

Looks fine - many thanks!