[PATCH] PCI: Disable NoSnoop and Relaxed ordering for Intel wireless BE200

[PATCH] PCI: Disable NoSnoop and Relaxed ordering for Intel wireless BE200

[Emmanuel Grumbach]

The Intel wireless BE200 device fails to copy the TLP Attributes from a
Request to the Completion.
Since there is no caching involved the device anyway, disable the
NoSnoop and Relaxed ordering on the root port.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
---
 drivers/pci/quirks.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index c0242f3e9f06..e9f070d07b2c 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4674,6 +4674,13 @@ static void quirk_chelsio_T5_disable_root_port_attributes(struct pci_dev *pdev)
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
 			 quirk_chelsio_T5_disable_root_port_attributes);
 
+/*
+ * The Intel wireless BE200 fails to copy TLP Attributes from a Request to the
+ * Completion it generates.
+ */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x272b,
+			 quirk_disable_root_port_attributes);
+
 /*
  * pci_acs_ctrl_enabled - compare desired ACS controls with those provided
  *			  by a device
-- 
2.54.0

Re: [PATCH] PCI: Disable NoSnoop and Relaxed ordering for Intel wireless BE200

[Lukas Wunner]

On Sun, Jun 21, 2026 at 09:54:51AM +0300, Emmanuel Grumbach wrote:
> The Intel wireless BE200 device fails to copy the TLP Attributes from a
> Request to the Completion.
> Since there is no caching involved the device anyway, disable the
> NoSnoop and Relaxed ordering on the root port.

Is there a public Specification Update which could be linked in the
commit message and/or code comment?

Thanks,

Lukas

Re: [PATCH] PCI: Disable NoSnoop and Relaxed ordering for Intel wireless BE200

[Grumbach, Emmanuel]

On Sun, 2026-06-21 at 10:10 +0200, Lukas Wunner wrote:
> On Sun, Jun 21, 2026 at 09:54:51AM +0300, Emmanuel Grumbach wrote:
> > The Intel wireless BE200 device fails to copy the TLP Attributes
> > from a
> > Request to the Completion.
> > Since there is no caching involved the device anyway, disable the
> > NoSnoop and Relaxed ordering on the root port.
> 
> Is there a public Specification Update which could be linked in the
> commit message and/or code comment?
> 
> 

Not really.
We just have tested our device with Jetson Thor and saw that it doesn't
work. Happens that the PCI controller on Jetson Thor is doing things
that very few PCI controllers do and this undercovered this bad
behavior on the BE200 side.

We don't have a more formal publication about this issue.


> Thanks,
> 
> Lukas