Re: [PATCH] PCI/portdev: Disable AER for Titan Ridge 4C 2018

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Tue, Jan 06, 2026 at 02:48:01PM -0600, Bjorn Helgaas wrote:
> [+cc Thunderbolt folks]
> 
> On Tue, Jan 06, 2026 at 11:00:52AM -0800, Kuppuswamy Sathyanarayanan wrote:
> > On 1/6/2026 10:20 AM, Atharva Tiwari wrote:
> > > Disable AER for Intel Titan Ridge 4C 2018
> > > (used in T2 iMacs, where the warnings appear)
> > > that generates continuous pcieport warnings. such as:
> > > 
> > > pcieport 0000:00:1c.4: AER: Correctable error message received from 0000:07:00.0
> > > pcieport 0000:07:00.0: PCIe Bus Error: severity=Correctable, type=Data Link Layer, (Receiver ID)
> > > pcieport 0000:07:00.0:   device [8086:15ea] error status/mask=00000080/00002000
> > > pcieport 0000:07:00.0:    [ 7] BadDLLP
> > > 
> > > (see: https://bugzilla.kernel.org/show_bug.cgi?id=220651)
> > > 
> > > macOS also disables AER for Thunderbolt devices and controllers in
> > > their drivers.
> > 
> > Why not disable it in BIOS or use noaer command line option?
> 
> If the kernel can figure this out by itself, we should do that so
> users don't have to debug issues and figure out how to disable in BIOS
> or use a command line option.
> 
> But if this is really a hardware issue, I would expect to see some
> reports on the web, and I can't find AER reports that mention these
> devices except this problem report.
> 
> Adding Thunderbolt folks in case they know about any errata.

I wonder if these AER messages are caused by PTM too?

Can you try the latest mainline. It has this commit:

  044b9f1a7f4f ("PCI/PTM: Enable only if device advertises relevant role")

and see if that changes anything?

> 
> > > Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
> > > ---
> > >  drivers/pci/pcie/portdrv.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c
> > > index 38a41ccf79b9..5330a679fcff 100644
> > > --- a/drivers/pci/pcie/portdrv.c
> > > +++ b/drivers/pci/pcie/portdrv.c
> > > @@ -240,7 +240,9 @@ static int get_port_device_capability(struct pci_dev *dev)
> > >  	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
> > >               pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
> > >  	    dev->aer_cap && pci_aer_available() &&
> > > -	    (pcie_ports_native || host->native_aer))
> > > +	    (pcie_ports_native || host->native_aer) &&
> > > +	    !(dev->vendor == PCI_VENDOR_ID_INTEL &&
> > > +		    (dev->device >= 0x15EA && dev->device <= 0x15EC)))
> > >  		services |= PCIE_PORT_SERVICE_AER;
> > >  #endif
> > >  
> > 
> > -- 
> > Sathyanarayanan Kuppuswamy
> > Linux Kernel Developer
> >