Re: help: screen tearing in guix

[Ekaitz Zarraga <ekaitz@elenq.tech>]

Hi Andre

> I've noticed that on my laptop's built-in screen there's some kind of
> weird "delay" going on.  For instance, the cursor lags behind after
> hitting Space.  On my external monitor, there are no issues at all.  If
> that matters, the built-in screen native resolution is almost 4K.  I've
> tried to play with the ModeLine settings in the past, but I wasn't able
> to solve it.
>
> I'm wondering if this "TearFree" option sounds like it could solve my
> issue.  Regardless, I'll give it a try.

In my laptop it didn't resolve tearing totally but it reduced it (I think,
I made the change recently and I was trained to ignore it :S)


> I also took a look at your config, and I noticed the last section
> relative to ModemManager.
>
> I've been playing with DIY keyboards (as you know) and I'm just curious
> why exactly ModemManager interferes with USB devices.
>
> For now I've solved the issue by adding the following udev rule:
>
> --8<---------------cut here---------------start------------->8---
> SUBSYSTEMS=="usb", ATTRS{idVendor}=="1b4f", ATTRS{idProduct}=="9205",
> TAG+="uaccess", ENV{ID_MM_DEVICE_IGNORE}="1"
> --8<---------------cut here---------------end--------------->8---
>
> My understand is that MM from "ID_MM_DEVICE_IGNORE" stands for
> ModemManager.  I'd like to get a deeper understanding of what's going
> on.  If you can share some pointers, I'd appreciate it.

The modem manager basically tries to know if anything you connected
is a modem so it sends AT commands to the serial devices right when
they are connected. That may interfere with your work.

The udev rule you added id more than enough I think. I'm a radical guy
so I just removed the modem manager service :)