Re: [PPC] Boot problems after the pci-v6.18-changes
- To: Herve Codina <herve.codina@bootlin.com>
- Cc: Manivannan Sadhasivam <mani@kernel.org>, Bjorn Helgaas <helgaas@kernel.org>, Lukas Wunner <lukas@wunner.de>, Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>, Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>, linux-pci@vger.kernel.org, mad skateman <madskateman@gmail.com>, "R.T.Dickinson" <rtd2@xtra.co.nz>, Christian Zigotzky <info@xenosoft.de>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, hypexed@yahoo.com.au, Darren Stevens <darren@stevens-zone.net>, debian-powerpc@lists.debian.org, Thomas Petazzoni <thomas.petazzoni@bootlin.com>
- Subject: Re: [PPC] Boot problems after the pci-v6.18-changes
- From: Christian Zigotzky <chzigotzky@xenosoft.de>
- Date: Thu, 16 Oct 2025 05:28:28 +0200
- Message-id: <[🔎] A1E3F83C-3AE8-43B7-9DCB-6C38C94F8953@xenosoft.de>
- In-reply-to: <[🔎] 20251015153442.423e2278@bootlin.com>
- References: <[🔎] 20251015153442.423e2278@bootlin.com>
> On 15 October 2025 at 03:51 pm, Herve Codina <herve.codina@bootlin.com> wrote:
>
> Hi Christian,
>
> On Wed, 15 Oct 2025 15:14:28 +0200
> Christian Zigotzky <chzigotzky@xenosoft.de> wrote:
>
>>> Am 15 October 2025 at 02:59 pm, Herve Codina <herve.codina@bootlin.com> wrote:
>>>
>>> Also when it boots, it is not easy to know about the problem root cause.
>>>
>>> In my case, it was not obvious to make the relationship on my side between
>>> my ping timings behavior and ASPM.
>>>
>>> Of course 'git bisect' helped a lot but can we rely on that for the average
>>> user?
>>>
>>> Best regards,
>>> Hervé
>>
>> I think I will revert these modifications for the RC2.
>
> I don't know what is the future of those modifications but maybe instead
> of fully reverting them, maybe you could perform calls to
> - pcie_clkpm_override_default_link_state() and
> - pcie_aspm_override_default_link_state()
> only if a new Kconfig symbol is enabled.
>
> Of course this symbols will be disabled by default but if you want some
> people to test behavior, it could be interesting to have the code
> available in the kernel.
>
> I don't know, this was just an idea.
>
> Of course, reverting the patch is simpler than adding this new Kconfig
> symbol.
>
> Best regards,
> Hervé
Hi Hervé,
Do you mean an option in the kernel config? If yes, then it is a great idea.
@Mani
Could you please create an option in the kernel config that enable or disable the power management for PCI and PCI Express?
If yes, then I don’t need to revert the changes due to boot issues and less performance.
Just for info: Simon Richter wrote:
Intel B580 on TalosII has trouble growing the BAR with 6.18.
Power management changes should not affect PPC because it is broken anyway — PCIe bridges are assumed to be managed by OpenFirmware, so the "pcieport" driver is not registered, so bridges have no power management, so downstream devices cannot enable it either.
- - -
Thanks,
Christian
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