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

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

[Karl Mehltretter]

__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

 drivers/pci/quirks.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 1aa87a3..47778c1 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3115,10 +3115,8 @@ static void __nv_msi_ht_cap_quirk(struct pci_dev *dev, int all)
 	 */
 	host_bridge = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus), 0,
 						  PCI_DEVFN(0, 0));
-	if (host_bridge == NULL) {
-		pci_warn(dev, "nv_msi_ht_cap_quirk didn't locate host bridge\n");
+	if (!host_bridge)
 		return;
-	}
 
 	pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE);
 	if (pos != 0) {

base-commit: c03c1a14507dfaf8b856c2608f9ac216021fc222
-- 
2.39.5 (Apple Git-154)

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

[Nicolas Chauvet]

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

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

[Bjorn Helgaas]

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.