netdev - pcie_get_minimum_link returns 0 width

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Message-ID: <979A8436335E3744ADCD3A9F2A2B68A52AD136BE@SJEXCHMB10.corp.ad.broadcom.com>
Date:	Sun, 25 Aug 2013 11:21:38 +0000
From:	"Yuval Mintz" <yuvalmin@...adcom.com>
To:	"jacob.e.keller@...el.com" <jacob.e.keller@...el.com>
cc:	"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: pcie_get_minimum_link returns 0 width

Hi,

I tried adding support for the newly added 'pcie_get_minimum_link' into the
bnx2x driver, but found out the some of my devices started showing width x0.

By adding debug prints, I've found out there were devices up the chain that
Showed 0 when their PCI_EXP_LNKSTA was read by said function.
However, when I tried looking via lspci the output claimed the width was x4.

lspci -vt output:
[0000:00]-+-00.0  Intel Corporation 5000P Chipset Memory Controller Hub
	     +-02.0-[09-12]--+-00.0-[0a-11]--+-00.0-[0b-0d]--
					     +-01.0-[0e-10]--+-00.0  Broadcom
					Corporation NetXtreme II BCM57710
					10-Gigabit PCIe [Everest]

Where:
00:02.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x4 Port
2 (rev 93)
09:00.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Upstream
Port (rev 01)
0a:01.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express
Downstream Port E2 (rev 01)
0e:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM57710
10-Gigabit PCIe [Everest] (rev 01)

The output for "lspci -vvvv | grep LnkSta for all four is:
LnkSta:	Speed 2.5GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt-
ABWMgmt-

But added prints inside the function's loop show:
LnkSta 1041 [000e:00.00]
LnkSta 0000 [000a:01.00]
LnkSta 0000 [0009:00.00]
LnkSta 3041 [0000:02.00]
(PCI_EXP_LNKSTA value, bus->number, PCI_SLOT, PCI_FUNC)

Thanks,
Yuval

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