Use i3 IPC to schedule xrandr block updates

[ammgws]

Xrandr block seems to have a few issues, which might be due to xrandr itself, but is exacerbated by the fact we call it every x seconds just to update the block.

I use sway not i3, but when reading through the i3 IPC docs, I saw that it apparently sends out events when there are RandR changes. Perhaps instead of polling xrandr every x seconds, we could instead subscribe to these events and only call xrandr when there are actual updates to display

https://i3wm.org/docs/ipc.html#_events

output (1)
Sent when RandR issues a change notification (of either screens, outputs, CRTCs or output properties).

Perhaps someone on i3 can look into it?

[ammgws]

@GladOSkar Do you use X?

Just need to run this and see what happens when you trigger events externally using xrandr or whatever tool:
i3-msg --type subscribe "['output']" --monitor

[GladOSkar]

Yep I'm running X.

but no, neither un-, replugging displays nor enabling/disabling displays using xrandr leads to any output from that command on my end.

However, i3-msg --type subscribe '["output"]' --monitor does output something when i enable/disable displays:

$ i3-msg --type subscribe '["output"]' --monitor
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}

[ammgws]

neither un-, replugging displays nor enabling/disabling displays using xrandr

That's a shame :( What about changing resolution or brightness using xrandr?

does output something when i enable/disable displays

^ How is this enable/disable different to the one above?

[GladOSkar]

They're the same, the i3-msg command is different: "['output']" vs '["output"]'.

[GladOSkar]

Oh and with the correct command it also outputs on (un)plugging displays. Sorry for the bad communication, i have covid rn and am still a bit hazy

[ammgws]

So to put it all together:

• plugging/unplugging monitor: {"change":"unspecified"}
• changing resolution: no output
• changing brightness: no output

?

[GladOSkar]

Changing resolution does also output

{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}
{"change":"unspecified"}

although probably mostly because the display is reinitialized which is basically like replugging.

Changing brightness yields no output.

[ammgws]

Oh then that means we could actually use this for xrandr instead of polling (but would have to remove support for brightness)