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References: <20240221233026.2915061-1-saravanak@google.com> <ZddNdqoqEz3BSXGI@smile.fi.intel.com>
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From: Saravana Kannan <saravanak@google.com>
Date: Thu, 22 Feb 2024 16:02:47 -0800
Message-ID: <CAGETcx_usPewYSPq=E_-_fuSge7H+YiQwS8Z4bbouX0SSH6sOg@mail.gmail.com>
Subject: Re: [PATCH v3 0/4] Add post-init-providers binding to improve
 suspend/resume stability
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>, "Rafael J. Wysocki" <rafael@kernel.org>, 
	Ard Biesheuvel <ardb@kernel.org>, Frank Rowand <frowand.list@gmail.com>, 
	Daniel Scally <djrscally@gmail.com>, Heikki Krogerus <heikki.krogerus@linux.intel.com>, 
	Sakari Ailus <sakari.ailus@linux.intel.com>, Len Brown <lenb@kernel.org>, kernel-team@android.com, 
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-efi@vger.kernel.org, linux-acpi@vger.kernel.org
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On Thu, Feb 22, 2024 at 5:34=E2=80=AFAM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Wed, Feb 21, 2024 at 03:30:20PM -0800, Saravana Kannan wrote:
> > This patch series adds a "post-init-providers" device tree binding that
> > can be used to break dependency cycles in device tree and enforce a mor=
e
> > determinstic probe/suspend/resume order. This will also improve the
> > stability of global async probing and async suspend/resume and allow us
> > to enable them more easily. Yet another step away from playing initcall
> > chicken with probing and step towards fully async probing and
> > suspend/resume.
>
> Do you know what is the state of affairs in ACPI? Is there any (similar)
> issue even possible?

I'm not very familiar with ACPI, but I wouldn't be surprised if ACPI
devices have cyclic dependencies. But then ACPI on a PC doesn't
typically have as many devices/drivers and ACPI might be hiding the
dependencies from the kernel. So maybe the possibility of a cycle
visible to the kernel might be low.

I would really like to see fw_devlink extended to ACPI (it's written
in a way to make that possible), but don't have enough knowledge to do
it.

-Saravana