QCA6174 pcie wifi: Add pci quirks

From: Ingmar Klein
Date: Fri Apr 09 2021 - 05:32:04 EST


Edit: Retry, as I did not consider, that my mail-client would make this
party html.

Dear maintainers,
I recently encountered an issue on my Proxmox server system, that
includes a Qualcomm QCA6174 m.2 PCIe wifi module.
https://deviwiki.com/wiki/AIRETOS_AFX-QCA6174-NX

On system boot and subsequent virtual machine start (with passed-through
QCA6174), the VM would just freeze/hang, at the point where the ath10k
driver loads.
Quick search in the proxmox related topics, brought me to the following
discussion, which suggested a PCI quirk entry for the QCA6174 in the kernel:
https://forum.proxmox.com/threads/pcie-passthrough-freezes-proxmox.27513/

I then went ahead, got the Proxmox kernel source (v5.4.106) and applied
the attached patch.
Effect was as hoped, that the VM hangs are now gone. System boots and
runs as intended.

Judging by the existing quirk entries for Atheros, I would think, that
my proposed "fix" could be included in the vanilla kernel.
As far as I saw, there is no entry yet, even in the latest kernel sources.

Thank you very much!
Best regards,
Ingmar
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 706f27a86a8e..ecfe80ec5b9c 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3584,6 +3584,7 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x0032, quirk_no_bus_reset);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x003c, quirk_no_bus_reset);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x0033, quirk_no_bus_reset);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x0034, quirk_no_bus_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x003e, quirk_no_bus_reset);

/*
* Root port on some Cavium CN8xxx chips do not successfully complete a bus