Re: [PATCH] PCI: quirks: Skip nv_msi_ht_cap_quirk when host bridge 00:00.0 is absent

[Bjorn Helgaas <helgaas@kernel.org>]

On Sat, Oct 24, 2026 at 07:52:02PM +0200, Nicolas Chauvet wrote:
> Le sam. 24 oct. 2026 à 19:25, Karl Mehltretter
> <kmehltretter@gmail.com> a écrit :
> >
> > __nv_msi_ht_cap_quirk() runs on all PCI_VENDOR_ID_NVIDIA devices to
> > enable or disable HyperTransport MSI mapping relative to a host bridge
> > at bus 0, slot 0, function 0.
> >
> > On NVIDIA Tegra SoCs (such as Tegra210 on Jetson Nano), the PCIe
> > controller exposes root ports at 00:01.0 and 00:02.0 with no device at
> > 00:00.0, and the root port's HT MSI mapping capability is already
> > disabled (found == 1). Looking up 00:00.0 returns NULL and logs a
> > false-positive warning on every boot:
> >
> >   pci 0000:00:02.0: nv_msi_ht_cap_quirk didn't locate host bridge
> >
> > Return silently when no 00:00.0 device exists on the domain, matching
> > nv_ht_enable_msi_mapping().
> >
> > Assisted-by: LLM
> > Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
> > ---
> > Observed on a Jetson Nano 4GB (Tegra210, p3450-0000) booting v7.3
> > (c03c1a14507d), where the Tegra PCIe controller (1003000.pcie)
> > enumerates the active root port at 0000:00:02.0 ([10de:0faf]) with no
> > 0000:00:00.0 device on bus 00:
> >
> >   pci 0000:00:02.0: [10de:0faf] type 01 class 0x060400 PCIe Root Port
> >   pci 0000:00:02.0: nv_msi_ht_cap_quirk didn't locate host bridge
> 
> There is this patch that was well tested on the tegra side (but likely
> less on the older x86 nv cases)
> https://codeberg.org/libre-tegra/linux/commit/63f7810994f4d2866a27b753ec8d5bc36e84373c

If anybody thinks this is better, please post with the appropriate
commit log and signed-off-by.