linux-kernel - Re: [PATCH 1/1] cxl/acpi.c: Add buggy BIOS hint for CXL ACPI lookup failure

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Date: Thu, 02 May 2024 10:34:33 -0700
From: PJ Waskiewicz <ppwaskie@...nel.org>
To: Dan Williams <dan.j.williams@...el.com>, Bjorn Helgaas
 <helgaas@...nel.org>
Cc: linux-cxl@...r.kernel.org, linux-pci@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] cxl/acpi.c: Add buggy BIOS hint for CXL ACPI lookup
 failure

On Wed, 2024-05-01 at 08:47 -0700, Dan Williams wrote:
> PJ Waskiewicz wrote:
> > Buggy BIOS, that above value resolves to CX02.  In fact, it
> > *should* be
> > 49.  This is very much a bug in the ACPI arena.
> 
> Ok, so back to this patch in question, my concern with upgrading:
> 
>     dev_err(dev, "unable to retrieve _UID\n");
> 
> ...to say "potentially buggy BIOS", is that same charge could be
> levied
> against all of the dev_warn() and dev_err() instances in
> drivers/cxl/acpi.c. So, it's not clear to me that cxl_acpi driver
> failures need to be more explicit.
> 
> Otherwise, pretty much any ACPI hiccup message in the kernel would be
> candidate for claiming "BIOS is busted".

I really do like your patch you proposed a few weeks back.  I'm happy
to pull that and test it if you'd like to move forward on that instead.

Personally, I think the amount of discussion generated around this
simple "the BIOS is broken" should warrant some level of change to help
others not in-the-know to understand why their shiny new CXL devices
fell over on init.  Whatever that change looks like though, I'm not
married to any particular approach.

-PJ