[Bug 215906] DMAR fault when connected usb hub (xhci_hcd)

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=215906

Michał Pecio (michal.pecio@gmail.com) changed:

           What    |Removed                     |Added
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                 CC|                            |michal.pecio@gmail.com

--- Comment #20 from Michał Pecio (michal.pecio@gmail.com) ---
By a complete accident I found that VL805 has a known bug where it overfetches
transfer rings:
https://github.com/raspberrypi/linux/issues/4685

Rolf, there is a workaround for similar bug in Zhaoxin hardware which may solve
your IOMMU faults.

Update to at least v6.6, or the latest v6.12 series if it's not a problem.

Run the following (if using a USB keyboard put it all in a script):
rmmod xhci_pci
rmmod xhci_hcd
modprobe xhci_hcd quirks=0x200000000000
modprobe xhci_pci

Verify that it worked:
dmesg |grep quirks
[122123.422469] xhci_hcd 0000:08:00.0: hcc params 0x002841eb hci version 0x100
quirks 0x0000200000000890
                                                                               
            ^-- here
And see if it helps.

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