Subject: Re: bug#66651: How to pass i915.enable_guc=0 in config.scm to prevent a 'wedged' GPU?

From: Csepp <[email-masked]>
Date: Fri, 20 Oct 2023 20:38:30 +0200

Hugo Buddelmeijer <[email-masked]> writes:

> The i915 driver will try to load the GuC firmware, at least for Iris
> Xe chips. Loading the GuC firmware fails because it is non-free and
> deblobbed. As a result, some software, like sway, will not work.
>
> It is possible to manually pass the i915.enable_guc=0 kernel parameter
> at boot from grub. Then everything works as intended. However, it
> seems not possible to set this parameter from config.scm.
>
> So at the moment my system is not fully declarative, as I have to type
> in a kernel parameter at boot; does anyone perhaps have advice on how
> can this be done better?
> ...

You can use the kernel-arguments option in the operating-system config.
Untested:
(kernel-arguments (cons "i915.enable_guc=0" %default-kernel-arguments))
This should work, in theory.

I suspect that the sysctl thing doesn't work because it is done too late
in the boot process.