linux-kernel - sriov capability enumeration returns false.

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Date:	Thu, 2 Jun 2016 07:59:24 +0100
From:	alan hopes <hopes.alan@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: sriov capability enumeration returns false.

Hi,

I am working on a simple graphics driver that just enumerates SRIOV
capability of PCI graphics controller.
During the init phase of the driver i.e. when the driver loads, I find
the PCI device based on my vendor ID and device ID, and then I check
if pDev->sriov and and I get the value false even though I can see the
SRIOV capability set using lspci.

Code for checking SRIOV capability:
pdev = get device based on device ID and vendor ID.
if (pDev->sriov)
      return false.

Output of lspci correctly reporting SRIOV capability at offset 0x330.

"
Capabilities: [330 v1] Single Root I/O Virtualization (SR-IOV)
                IOVCap: Migration-, Interrupt Message Number: 000
                IOVCtl: Enable- Migration- Interrupt- MSE- ARIHierarchy+
                IOVSta: Migration-
                Initial VFs: 16, Total VFs: 16, Number of VFs: 0,
Function Dependency Link: 00
                VF offset: 256, stride: 1, Device ID: xxxx
                Supported Page Size: 00000553, System Page Size: 00000001
                Region 0: Memory at 0000021ee0000000 (64-bit, prefetchable)
                Region 2: Memory at 0000021ff0000000 (64-bit, prefetchable)
                Region 5: Memory at 98c00000 (32-bit, non-prefetchable)
                VF Migration: offset: 00000000, BIR: 0
"

I can see, using lspci, that card has been setup properly with SRIOV
enabled. But then why my driver is not able to see this value. I think
I am missing something, Please can you suggest what I am doing wrong
here..

Thanks
Alan