From: Vinod Koul <vkoul@kernel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Cc: "Neil Armstrong" <neil.armstrong@linaro.org>,
"Krishna Chaitanya Chundru" <krishna.chundru@oss.qualcomm.com>,
"Philipp Zabel" <p.zabel@pengutronix.de>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 1/5] phy: qcom: qmp-pcie: Skip PHY reset if already up
Date: Wed, 14 Jan 2026 15:06:50 +0530 [thread overview]
Message-ID: <aWdjsvAPjyJkplMD@vaman> (raw)
In-Reply-To: <cvxvq7f2ku6aq5gbbqav42ckqk2raesbxq2bx46mxvapcza5v4@5zuyjdtn5us2>
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
WARNING: multiple messages have this Message-ID (diff)
From: Vinod Koul <vkoul@kernel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Cc: "Neil Armstrong" <neil.armstrong@linaro.org>,
"Krishna Chaitanya Chundru" <krishna.chundru@oss.qualcomm.com>,
"Philipp Zabel" <p.zabel@pengutronix.de>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 1/5] phy: qcom: qmp-pcie: Skip PHY reset if already up
Date: Wed, 14 Jan 2026 15:06:50 +0530 [thread overview]
Message-ID: <aWdjsvAPjyJkplMD@vaman> (raw)
In-Reply-To: <cvxvq7f2ku6aq5gbbqav42ckqk2raesbxq2bx46mxvapcza5v4@5zuyjdtn5us2>
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
--
linux-phy mailing list
linux-phy@lists.infradead.org
https://lists.infradead.org/mailman/listinfo/linux-phy
next prev parent reply other threads:[~2026-01-14 9:36 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-09 7:21 [PATCH 0/5] PCI: qcom: Add link retention support Krishna Chaitanya Chundru
2026-01-09 7:21 ` Krishna Chaitanya Chundru
2026-01-09 7:21 ` [PATCH 1/5] phy: qcom: qmp-pcie: Skip PHY reset if already up Krishna Chaitanya Chundru
2026-01-09 7:21 ` Krishna Chaitanya Chundru
2026-01-09 9:23 ` Abel Vesa
2026-01-09 9:23 ` Abel Vesa
2026-01-09 13:08 ` Dmitry Baryshkov
2026-01-09 13:08 ` Dmitry Baryshkov
2026-01-09 13:10 ` Neil Armstrong
2026-01-09 13:10 ` Neil Armstrong
2026-01-09 14:03 ` Dmitry Baryshkov
2026-01-09 14:03 ` Dmitry Baryshkov
2026-01-14 9:36 ` Vinod Koul [this message]
2026-01-14 9:36 ` Vinod Koul
2026-02-16 14:53 ` Manivannan Sadhasivam
2026-02-16 14:53 ` Manivannan Sadhasivam
2026-02-16 14:56 ` Konrad Dybcio
2026-02-16 14:56 ` Konrad Dybcio
2026-01-09 7:21 ` [PATCH 2/5] PCI: dwc: Add support for retaining link during host init Krishna Chaitanya Chundru
2026-01-09 7:21 ` Krishna Chaitanya Chundru
2026-01-09 15:53 ` Bjorn Helgaas
2026-01-09 15:53 ` Bjorn Helgaas
2026-01-12 11:29 ` Konrad Dybcio
2026-01-12 11:29 ` Konrad Dybcio
2026-01-22 8:55 ` Krishna Chaitanya Chundru
2026-01-22 8:55 ` Krishna Chaitanya Chundru
2026-01-09 7:21 ` [PATCH 3/5] PCI: qcom: Keep PERST# GPIO state as-is during probe Krishna Chaitanya Chundru
2026-01-09 7:21 ` Krishna Chaitanya Chundru
2026-01-09 11:14 ` Konrad Dybcio
2026-01-09 11:14 ` Konrad Dybcio
2026-02-16 14:58 ` Manivannan Sadhasivam
2026-02-16 14:58 ` Manivannan Sadhasivam
2026-01-09 7:21 ` [PATCH 4/5] PCI: qcom: Add link retention support Krishna Chaitanya Chundru
2026-01-09 7:21 ` Krishna Chaitanya Chundru
2026-02-16 15:08 ` Manivannan Sadhasivam
2026-02-16 15:08 ` Manivannan Sadhasivam
2026-01-09 7:21 ` [PATCH 5/5] PCI: qcom: enable Link retain logic for Hamoa Krishna Chaitanya Chundru
2026-01-09 7:21 ` Krishna Chaitanya Chundru
2026-01-09 13:09 ` Dmitry Baryshkov
2026-01-09 13:09 ` Dmitry Baryshkov
2026-01-22 8:59 ` Krishna Chaitanya Chundru
2026-01-22 8:59 ` Krishna Chaitanya Chundru
2026-01-15 2:16 ` [PATCH 0/5] PCI: qcom: Add link retention support Qiang Yu
2026-01-15 2:16 ` Qiang Yu
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