GPU compatibility with Linux-libre

GPU compatibility with Linux-libre

[Bone Baboon]

This is a summary of what I have learned about GPU compatibility with
Linux-libre from the help I received in these email threads: 

Start Xorg server using xinit manually
https://lists.gnu.org/archive/html/help-guix/2021-03/msg00197.html

Two more computers unable to start X with GDM
https://lists.gnu.org/archive/html/help-guix/2021-03/msg00250.html

Starting Sway a Wayland window manager
https://lists.gnu.org/archive/html/help-guix/2021-03/msg00268.html

Corrections or further information is appreciated.

Testing was done on two i686 computers and three x86_64 computers.

1) After installing the Guix operating system on a computer check if the
directory /dev/dri/ exists.
** If it does *not* exist then your computer's GPU is *not* compatible
   with Linux-libre.
** If it does exist then your computer's GPU is compatible with
   Linux-libre.

2) If your GPU is not compatible with Linux-libre (see 1 above) then
Xorg server and Wayland window managers will not work.

3) If your GPU is compatible with Linux-libre (see 1 above) but you have
trouble getting Xorg server to work consider using a Wayland window
manager.  I was able to get Sway a Wayland window manager working on a
computer that Xorg server was not working with.

Note: If you use a Wayland window manager some programs that work with
Xorg server may not work.  There may be alternatives programs for those
that do not work.  I found this helpful:
https://github.com/natpen/awesome-wayland

GPU compatibility with Linux-libre

[Bone Baboon]

This message has two parts about GPU compatibility with Linux-libre.
1) Manual Warning
2) Summary

# Manual Warning

I originally posted the message below on the help mailing list.  It is
reposted here for two reasons.

* It was suggested that the help mailing list may not be the correct
  mailing list. 
  https://lists.gnu.org/archive/html/help-guix/2021-04/msg00229.html

* Someone else recently had the same issue with GPU compatibility.
  https://issues.guix.gnu.org/issue/48343

From the original message:

```
I found the Hardware Considerations section of the Guix manual very
helpful.  I was prepared for the issue of WiFi device compatibility.
However I was surprised by GPU compatibility.

I think it would be helpful to have a warning about GPU compatibility.
This would help someone who is looking at buying a computer by bringing
GPU compatibility to their attention.

I found the WiFi device warning with specific hardware that is known to
work very helpful.  Maybe an equivalent could be done for GPUs

...

I appreciate that this extra warning may discourage some people from
trying Guix.  I think it would still be good to warn people about
potential problems so that they are not surprised.
```

# Summary

I have been sharing a link to "GPU compatibility with Linux-libre"
https://lists.gnu.org/archive/html/help-guix/2021-04/msg00220.html on
the Guix mailing lists and in #guix when people were asking for help
about getting a graphical environment setup in Guix. The feedback I have
received is that it was helpful.  I would appreciate any correction or
additions as I do not want to misinform people.