On 11/11/2011 12:41 PM, James Paradis wrote:
Hmmm... would it be better to do this as a quirk or as a boot
parameter? I've heard reports that other systems may be running
Hearsay? if you have definite cases, then please share them,
so folks know when to flip the boot parameter on.
note: it would have to be an early boot param as well.
into similar issues... if we don't know exactly which systems
these are then maybe a boot parameter would be a more flexible
approach...
--jim
----- Original Message -----
On 11/10/2011 09:31 AM, Matthew Wilcox wrote:
On Thu, Nov 10, 2011 at 09:00:13AM -0500, Prarit Bhargava wrote:
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.
@@ -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;
dmi_name_in_vendors is relatively expensive, so the order of these
two
should be swapped, at least:
if (parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM&&
!dmi_name_in_vendors("ftServer"))
Plus, this gets called for every PCI bridge. We should be caching
it
somewhere, so it's only called once.
Then i recommend a dmi_name_in_vendors() check at init; stick result
in
global (or local static), and then it's not exec'd on each bridge,
just
a simple flag check.
If that's the case, I'd re-cast my vote for putting the code in
pci_quirks
with an export, so it is tracked as a quirk. that may get messy
wrt other arches though (the export in common code; not sure if
quirks is
included on all arches).
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