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Date: Mon, 26 Feb 2024 10:25:12 +0000
To: bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
From: Edmund Raile <edmund.raile@proton.me>
Cc: Edmund Raile <edmund.raile@proton.me>
Subject: [PATCH] PCI: Mark LSI FW643 to avoid bus reset
Message-ID: <20240226102354.86757-1-edmund.raile@proton.me>
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Using LSI / Agere FW643 with vfio-pci will issue an FLreset, causing
a broken link only recoverable by removing power (power-off /
suspend + rescan). Prevent this bus reset.
With this change, the device can be assigned to VMs with VFIO.

Signed-off-by: Edmund Raile <edmund.raile@proton.me>
---
Usefulness:
The LSI FW643 PCIe->FireWire 800 interface may be EOL but it is
the only one that does not use a PCIe->PCI bridge.
It was used in the following Apple machines:
MacBookPro10,1
MacBookPro9,2
MacBookPro6,2
MacBookPro5,1
Macmini6,1
Macmini3,1
iMac12,2
iMac9,1
iMac8,1
It is reliable and enables FireWire audio interfaces to be used
on modern machines.
Virtualization allows for flexible access to professional audio
software.

Implementation:
PCI_VENDOR_ID_ATT was reused as they are identical and I am
uncertain it is correct to add another ID for LSI to pci_ids.h.
 drivers/pci/quirks.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index d797df6e5f3e..a6747e1b86da 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3765,6 +3765,15 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x00=
3e, quirk_no_bus_reset);
  */
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CAVIUM, 0xa100, quirk_no_bus_reset)=
;
=20
+/*
+ * Using LSI / Agere FW643 with vfio-pci will issue an FLreset, causing
+ * a broken link only recoverable by removing power (power-off /
+ * suspend + rescan). Prevent this bus reset.
+ * With this change, the device can be assigned to VMs with VFIO.
+ */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATT, 0x5900, quirk_no_bus_reset);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATT, 0x5901, quirk_no_bus_reset);
+
 /*
  * Some TI KeyStone C667X devices do not support bus/hot reset.  The PCIES=
S
  * automatically disables LTSSM when Secondary Bus Reset is received and
--=20
2.43.0