Re: [PATCH 00/19] init: discoverable root partitions, a.k.a. an omittable "root=" cmdline option

From: Al Viro <viro@zeniv.linux.org.uk>
To: Vincent Mailhol <mailhol@kernel.org>
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Subject: Re: [PATCH 00/19] init: discoverable root partitions, a.k.a. an omittable "root=" cmdline option
Date: Mon, 15 Jun 2026 18:04:32 +0100	[thread overview]
Message-ID: <20260615170432.GW2636677@ZenIV> (raw)
In-Reply-To: <20260615-discoverable-root_partitions-v1-0-39c78fac42e2@kernel.org>

On Mon, Jun 15, 2026 at 06:08:56PM +0200, Vincent Mailhol wrote:

> Tested with GRUB, which implements the LoaderDevicePartUUID EFI variable
> in its bli module [3]. With this, I was able to boot a kernel with a
> completely empty cmdline and no initrd.
> 
> [1] The Discoverable Partitions Specification (DPS)
> Link: https://uapi-group.org/specifications/specs/discoverable_partitions_specification/
> 
> [2] systemd-gpt-auto-generator
> Link: https://www.freedesktop.org/software/systemd/man/latest/systemd-gpt-auto-generator.html
> 
> [3] GRUB -- §16.2 bli
> Link: https://www.gnu.org/software/grub/manual/grub/html_node/bli_005fmodule.html

So what does that thing, tied to EFI as it is, have to do with architectures where
	* firmware is rather unlike EFI
	* firmware wouldn't know what to do with GPT
	* GRUB is *not* ported to, let alone used
such as, say it, the very first one mentioned at your [1]?

Or is that conditional upon "if anyone wants to design replacement firmware
for those, and if they agree to follow our wishlist"?