[PATCH] PCI: Avoid D3 on PLX PEX 8532/8533/8548 downstream ports

[Imre Kaloz <kaloz@kernel.org>]

Runtime PM suspends an idle downstream port of a PLX/Broadcom PEX
8532/8533/8548 switch to D3hot, but that takes the whole switch down
with it: any device behind another port of the same switch then
faults with a fatal bus error on its next access, e.g. mptsas probe
on a Sun Ultra 45.

This surfaced on sparc64 once commit a5fb3ff63287 ("PCI: Allow PCI
bridges to go to D3Hot on all non-x86") let bridges enter D3hot. Keep
these downstream ports out of D3 by setting PCI_DEV_FLAGS_NO_D3.

Fixes: a5fb3ff63287 ("PCI: Allow PCI bridges to go to D3Hot on all non-x86")
Cc: stable@vger.kernel.org
Signed-off-by: Imre Kaloz <kaloz@kernel.org>
---
 drivers/pci/quirks.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index de9bbccda21f..a3c9250182a6 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2381,6 +2381,24 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9050,
 DECLARE_PCI_FIXUP_HEADER(0x1402, 0x2000, quirk_plx_pci9050);
 DECLARE_PCI_FIXUP_HEADER(0x1402, 0x2600, quirk_plx_pci9050);
 
+/*
+ * An idle downstream port of a PLX/Broadcom PEX 8532/8533/8548 switch
+ * autosuspends into D3hot, and that takes the whole switch down with
+ * it -- any device behind another port of the same switch then sees a
+ * fatal, non-recoverable bus fault on its next access. Keep these
+ * ports out of D3 entirely.
+ */
+static void quirk_plx_pex_no_d3(struct pci_dev *dev)
+{
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) {
+		dev->dev_flags |= PCI_DEV_FLAGS_NO_D3;
+		pci_info(dev, "avoiding D3 on this downstream port\n");
+	}
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_PLX, 0x8532, quirk_plx_pex_no_d3);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_PLX, 0x8533, quirk_plx_pex_no_d3);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_PLX, 0x8548, quirk_plx_pex_no_d3);
+
 static void quirk_netmos(struct pci_dev *dev)
 {
 	unsigned int num_parallel = (dev->subsystem_device & 0xf0) >> 4;

base-commit: fe2ec83746e501645709761605c2464a44fd2929
-- 
2.47.3