linux-kernel - RE: [PATCH 0/2] PCI/ASPM: Allow quirks to avoid L0s and L1

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Message-ID:
 <AS8PR04MB8833A6EA37021A6754A9F6128CC3A@AS8PR04MB8833.eurprd04.prod.outlook.com>
Date: Fri, 7 Nov 2025 02:33:23 +0000
From: Hongxing Zhu <hongxing.zhu@....com>
To: Bjorn Helgaas <helgaas@...nel.org>, "linux-pci@...r.kernel.org"
	<linux-pci@...r.kernel.org>
CC: Christian Zigotzky <chzigotzky@...osoft.de>, Manivannan Sadhasivam
	<mani@...nel.org>, mad skateman <madskateman@...il.com>, "R . T . Dickinson"
	<rtd2@...a.co.nz>, Darren Stevens <darren@...vens-zone.net>, John Paul Adrian
 Glaubitz <glaubitz@...sik.fu-berlin.de>, Lukas Wunner <lukas@...ner.de>,
	luigi burdo <intermediadc@...mail.com>, Al <al@...azap.net>, Roland
	<rol7and@....com>, "hypexed@...oo.com.au" <hypexed@...oo.com.au>,
	"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
	"debian-powerpc@...ts.debian.org" <debian-powerpc@...ts.debian.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Bjorn Helgaas
	<bhelgaas@...gle.com>
Subject: RE: [PATCH 0/2] PCI/ASPM: Allow quirks to avoid L0s and L1

> -----Original Message-----
> From: Bjorn Helgaas <helgaas@...nel.org>
> Sent: 2025年11月7日 2:37
> To: linux-pci@...r.kernel.org
> Cc: Christian Zigotzky <chzigotzky@...osoft.de>; Manivannan Sadhasivam
> <mani@...nel.org>; mad skateman <madskateman@...il.com>; R . T .
> Dickinson <rtd2@...a.co.nz>; Darren Stevens <darren@...vens-zone.net>;
> John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>; Lukas Wunner
> <lukas@...ner.de>; luigi burdo <intermediadc@...mail.com>; Al
> <al@...azap.net>; Roland <rol7and@....com>; Hongxing Zhu
> <hongxing.zhu@....com>; hypexed@...oo.com.au;
> linuxppc-dev@...ts.ozlabs.org; debian-powerpc@...ts.debian.org;
> linux-kernel@...r.kernel.org; Bjorn Helgaas <bhelgaas@...gle.com>
> Subject: [PATCH 0/2] PCI/ASPM: Allow quirks to avoid L0s and L1
> 
> From: Bjorn Helgaas <bhelgaas@...gle.com>
> 
> We enabled ASPM too aggressively in v6.18-rc1.  f3ac2ff14834 ("PCI/ASPM:
> Enable all ClockPM and ASPM states for devicetree platforms") enabled
> ASPM L0s, L1, and (if advertised) L1 PM Substates.
> 
> L1 PM Substates and Clock PM in particular are a problem because they
> depend on CLKREQ# and sometimes device-specific configuration, and none
> of this is discoverable in a generic way.
> 
> df5192d9bb0e ("PCI/ASPM: Enable only L0s and L1 for devicetree platforms")
> (v6.18-rc3) backed off and omitted Clock PM and L1 Substates.
> 
> L0s and L1 are generically discoverable, but some devices advertise them
> even though they don't work correctly.  This series is a way to avoid L0s and
> L1 in that case.
> 
> Bjorn Helgaas (2):
>   PCI/ASPM: Cache Link Capabilities so quirks can override them
>   PCI/ASPM: Avoid L0s and L1 on Freescale Root Ports

Tested-by: Richard Zhu <hongxing.zhu@....com>

Best Regards
Richard Zhu

> 
>  drivers/pci/pcie/aspm.c | 42 ++++++++++++++++++++---------------------
>  drivers/pci/probe.c     |  5 ++---
>  drivers/pci/quirks.c    | 12 ++++++++++++
>  include/linux/pci.h     |  1 +
>  4 files changed, 36 insertions(+), 24 deletions(-)
> 
> --
> 2.43.0