Stratus systems have a hierarchy that includes a PCIE Downstream bridge
connected to a PCIE Upstream bridge and a PCI Downstream bridge. The system
boots with this wrong hierarchy into a crippled mode (USB doesn't work,
network doesn't work ...). Avoiding the Downstream bridge check in
only_one_child() causes all the bridges to be enumerated and the system
to function properly.
Unfortunately this hardware is currently available so we should at least
keep it functional.
Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: mstowe@xxxxxxxxxx
Cc: ddutile@xxxxxxxxxx
Cc: jparadis@xxxxxxxxxx
Cc: matthew.wilcox@xxxxxxxxxxxxxxx
Cc: jbarnes@xxxxxxxxxxxxxxxx
---
drivers/pci/probe.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 04e74f4..bc76812 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/cpumask.h>
#include <linux/pci-aspm.h>
+#include <linux/dmi.h>
#include "pci.h"
#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
@@ -1275,7 +1276,15 @@ static int only_one_child(struct pci_bus *bus)
struct pci_dev *parent = bus->self;
if (!parent || !pci_is_pcie(parent))
return 0;
- if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
+ if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT)
+ return 1;
+ /*
+ * Stratus/NEC ftServer systems have a broken PCIE hierarchy in which
+ * one upstream and one downstream port are plugged into a downstream
+ * port. Avoiding the downstream port check here results in a
+ * functional system.
+ */
+ if (!dmi_name_in_vendors("ftServer") &&
parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
return 1;
return 0;
--
1.7.1
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