linux-kernel - Re: [PATCH] schemas: pci: Document PCIe T_POWER

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Message-ID: <7v5bmbke37qy7e5qns7j7sjlcutdu53nbutgfo6tn47qkojxjy@phwcchh5gs5q>
Date: Thu, 6 Nov 2025 18:08:21 +0530
From: Manivannan Sadhasivam <mani@...nel.org>
To: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Cc: andersson@...nel.org, robh@...nel.org, 
	manivannan.sadhasivam@...aro.org, krzk@...nel.org, helgaas@...nel.org, 
	linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org, lpieralisi@...nel.org, kw@...ux.com, 
	conor+dt@...nel.org, linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org, 
	devicetree-spec@...r.kernel.org, quic_vbadigan@...cinc.com
Subject: Re: [PATCH] schemas: pci: Document PCIe T_POWER_ON

On Thu, Nov 06, 2025 at 05:09:51PM +0530, Krishna Chaitanya Chundru wrote:
> From PCIe r6, sec 5.5.4 & sec 5.5.5 T POWER_ON is the minimum amount

T_POWER_ON

You should provide reference to the Table 5-11, where T_POWER_ON is described.

> of time

"(in us)"

> that each component must wait in L1.2.Exit after sampling CLKREQ#
> asserted before actively driving the interface to ensure no device is ever
> actively driving into an unpowered component and these values are based on
> the components and AC coupling capacitors used in the connection linking
> the two components.
> 
> Certain controllers may need to program this before enumeration, such
> controllers can use this property to program it.
> 

I'd remove this statement and just mention that this property should be used to
indicate the T_POWER_ON for each Root Port.

- Mani

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