linux-kernel - Re: [PATCH v3 0/7] PCI/pwrctrl: Major rework to integrate pwrctrl devices with controller drivers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aVOrC85Y6mCYU8xL@ryzen>
Date: Tue, 30 Dec 2025 11:35:55 +0100
From: Niklas Cassel <cassel@...nel.org>
To: manivannan.sadhasivam@....qualcomm.com
Cc: Manivannan Sadhasivam <mani@...nel.org>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kwilczynski@...nel.org>,
	Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
	Bartosz Golaszewski <brgl@...ev.pl>, linux-pci@...r.kernel.org,
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Chen-Yu Tsai <wens@...nel.org>,
	Brian Norris <briannorris@...omium.org>,
	Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>,
	Alex Elder <elder@...cstar.com>,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
	Chen-Yu Tsai <wenst@...omium.org>
Subject: Re: [PATCH v3 0/7] PCI/pwrctrl: Major rework to integrate pwrctrl
 devices with controller drivers

On Mon, Dec 29, 2025 at 10:56:51PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> Hi,
> 
> This series provides a major rework for the PCI power control (pwrctrl)
> framework to enable the pwrctrl devices to be controlled by the PCI controller
> drivers.
> 
> Problem Statement
> =================
> 
> Currently, the pwrctrl framework faces two major issues:
> 
> 1. Missing PERST# integration

AFAICT, and from reading your reply here:

https://lore.kernel.org/linux-pci/ibvk4it7th4bi6djoxshjqjh7zusbulzpndac5jtqkqovvgcei@5sycben7pqkk/

  I suppose maybe you plan to enhance pwrctrl so it can assert/deassert
  individual PERST# in the hierarchy?

"No, that plan has been dropped for good. For now, PERST# will be handled
entirely by the controller drivers. Sharing the PERST# handling with pwrctrl
proved to be a pain and it looks more clean (after the API introduction) to
handle PERST# in controller drivers."

Thus, it seems that even after this series, pwrctrl will be missing PERST#
integration. Perhaps the cover letter could be rephrased to more clearly
highlight this.

Because it seems a bit weird that the first point of the problem statement
(missing PERST# integration) will still be the case after this series.

Kind regards,
Niklas