Thread (9 messages) 9 messages, 3 authors, 2015-09-30

Re: [PATCH v3 2/2] PCI: Add support for Enhanced Allocation devices

From: David Daney <hidden>
Date: 2015-09-29 23:53:37
Also in: linux-pci, lkml

On 09/29/2015 03:47 PM, Sean O. Stalley wrote:
[...]
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diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6a9a111..7c60b16 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2148,6 +2148,284 @@ void pci_pm_init(struct pci_dev *dev)
  	}
  }

+static unsigned long pci_ea_set_flags(struct pci_dev *dev, u8 prop)
+{
+	unsigned long flags = IORESOURCE_PCI_FIXED | IORESOURCE_SIZEALIGN;
Why did you add the IORESOURCE_SIZEALIGN flag? EA allows for unaligned resources.
pci_bus_assign_resources() fails causing the devices to be unusable
if resource_alignment() returns zero.  The easiest fix for this was
to specify IORESOURCE_SIZEALIGN.

An alternative would be to change the code in setup-bus.c so that
for IORESOURCE_PCI_FIXED resources, it didn't barf.
I would do this alternative, but with a IORESOURCE_PCI_EA flag.
I don't think we need IORESOURCE_PCI_EA.  If a resource is tagged as 
IORESOURCE_PCI_FIXED that means that it cannot be changed, we shouldn't 
care why it is fixed (due to an EA capability for example).  We just 
need to gracefully handle IORESOURCE_PCI_FIXED in the places where 
things currently go wrong.

David Daney
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