linux-kernel - Re: [PATCH 1/5] phy: qcom: qmp-pcie: Skip PHY reset if already up

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: <aWdjsvAPjyJkplMD@vaman>
Date: Wed, 14 Jan 2026 15:06:50 +0530
From: Vinod Koul <vkoul@...nel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Neil Armstrong <neil.armstrong@...aro.org>,
	Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Jingoo Han <jingoohan1@...il.com>,
	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>,
	linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org
Subject: Re: [PATCH 1/5] phy: qcom: qmp-pcie: Skip PHY reset if already up

On 09-01-26, 16:03, Dmitry Baryshkov wrote:
> On Fri, Jan 09, 2026 at 02:10:49PM +0100, Neil Armstrong wrote:
> > On 1/9/26 14:08, Dmitry Baryshkov wrote:
> > > On Fri, Jan 09, 2026 at 12:51:06PM +0530, Krishna Chaitanya Chundru wrote:
> > > > If the bootloader has already powered up the PCIe PHY, doing a full
> > > > reset and waiting for it to come up again slows down boot time.
> > > 
> > > How big is the delay caused by it?
> > > 
> > > > 
> > > > Add a check for PHY status and skip the reset steps when the PHY is
> > > > already active. In this case, only enable the required resources during
> > > > power-on. This works alongside the existing logic that skips the init
> > > > sequence.
> > > 
> > > Can we end up in a state where the bootloader has mis-setup the link? Or
> > > the link going bad because of any glitch during the bootup?
> > 
> > Good question, can we add a module parameter to force a full reset of the PHY in case
> > the bootloader is buggy ?
> 
> I'd suggest a simpler thing: if the reset was skipped, reset the PHY in
> case of an error and retry. That's also one of the reasons why I asked
> for skip_reset not to be the persistent value.

That is a better suggestion. Helps skips if it is configured and way to
recover if buggy

-- 
~Vinod