[PPC] Boot problems after the pci-v6.18-changes

[Manivannan Sadhasivam]

On Sat, Oct 11, 2025 at 07:25:26AM +0200, Lukas Wunner wrote:
> [cc += Mani]
> 
> On Sat, Oct 11, 2025 at 07:12:49AM +0200, Christian Zigotzky wrote:
> > On 09 October 2025 at 07:37 am, Lukas Wunner wrote:
> > > On Thu, Oct 09, 2025 at 06:54:58AM +0200, Christian Zigotzky wrote:
> > > > On 08 October 2025 at 09:51 pm, Bjorn Helgaas wrote:
> > > > > On Wed, Oct 08, 2025 at 06:35:42PM +0200, Christian Zigotzky wrote:
> > > > > > Our PPC boards [1] have boot problems since the pci-v6.18-changes. [2]
> > > > > > 
> > > > > > Without the pci-v6.18-changes, the PPC boards boot without any problems.
> > > > > > 
> > > > > > Boot log with error messages:
> > > > > > https://github.com/user-attachments/files/22782016/Kernel_6.18_with_PCI_changes.log
> > > > > > 
> > > > > > Further information: https://github.com/chzigotzky/kernels/issues/17
> > > > > Do you happen to have a similar log from a recent working kernel,
> > > > > e.g., v6.17, that we could compare with?
> > > > Thanks for your answer. Here is a similar log from the kernel 6.17.0:
> > > > https://github.com/user-attachments/files/22789946/Kernel_6.17.0_Cyrus_Plus_board_P5040.log
> > > These lines are added in v6.18:
> > > 
> > >    pci 0000:01:00.0: ASPM: DT platform, enabling L0s-up L0s-dw L1 ASPM-L1.1 ASPM-L1.2 PCI-PM-L1.1 PCI-PM-L1.2
> > >    pci 0000:01:00.0: ASPM: DT platform, enabling ClockPM
> > >    pci 0001:01:00.0: ASPM: DT platform, enabling L0s-up L0s-dw L1 ASPM-L1.1 ASPM-L1.2 PCI-PM-L1.1 PCI-PM-L1.2
> > >    pci 0001:01:00.0: ASPM: DT platform, enabling ClockPM
> > >    pci 0001:03:00.0: ASPM: DT platform, enabling L0s-up L0s-dw L1 ASPM-L1.1 ASPM-L1.2 PCI-PM-L1.1 PCI-PM-L1.2
> > >    pci 0001:03:00.0: ASPM: DT platform, enabling ClockPM
> > > 
> > > Possible candidate:
> > > 
> > > f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree platforms")
> > 
> > After reverting the commit f3ac2ff14834, the kernel boots without any
> > problems.
> > 
> > f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree
> > platforms") is the bad commit.
> 
> Hi Mani, your commit f3ac2ff14834 is causing a regression on certain
> powerpc machines.  Any ideas?
> 

Hi Lukas,

Thanks for looping me in. The referenced commit forcefully enables ASPM on all
DT platforms as we decided to bite the bullet finally.

Looks like the device (0000:01:00.0) doesn't play nice with ASPM even though it
advertises ASPM capability.

Christian, could you please test the below change and see if it fixes the issue?

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 214ed060ca1b..e006b0560b39 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2525,6 +2525,15 @@ static void quirk_disable_aspm_l0s_l1(struct pci_dev *dev)
  */
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ASMEDIA, 0x1080, quirk_disable_aspm_l0s_l1);
 
+
+static void quirk_disable_aspm_all(struct pci_dev *dev)
+{
+       pci_info(dev, "Disabling ASPM\n");
+       pci_disable_link_state(dev, PCIE_LINK_STATE_ALL);
+}
+
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x6738, quirk_disable_aspm_all);
+
 /*
  * Some Pericom PCIe-to-PCI bridges in reverse mode need the PCIe Retrain
  * Link bit cleared after starting the link retrain process to allow this


Going forward, we should be quirking the devices if they behave erratically.

- Mani

-- 
மணிவண்ணன் சதாசிவம்