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From: Bjorn Helgaas <bhelgaas@google.com>
Date: Fri, 12 Sep 2014 14:38:12 -0600
Message-ID: <CAErSpo7knOrXNqimWXP0t7eGWYZhEhy1=i6358pBtk9Nd5RO8g@mail.gmail.com>
Subject: Re: [BUG] Bisected Problem with LSI PCI FC Adapter
To: Dirk Gouders <dirk@gouders.net>
Cc: Yinghai Lu <yinghai@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andreas Noever <andreas.noever@gmail.com>,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
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On Fri, Sep 12, 2014 at 2:05 PM, Dirk Gouders <dirk@gouders.net> wrote:
> ...
> Yinghai,
>
> I now applied your patches and tested them:
>
> echo 1 > /sys/bus/pci/devices/0000\:00\:0a.0/pcie_link_disable
> echo 0 > /sys/bus/pci/devices/0000\:00\:0a.0/pcie_link_disable
>
> The FC Adapter did not show up, this is the dmesg output (I also tested
> with 0b.0):
>
> [  143.294168] pcieport 0000:00:0a.0: pcie_link_disable_set: lnk_ctrl = 18
> [  148.284456] pcieport 0000:00:0a.0: pcie_link_disable_set: lnk_ctrl = 8
> [  304.065942] pcieport 0000:00:0b.0: pcie_link_disable_set: lnk_ctrl = 18
> [  309.035278] pcieport 0000:00:0b.0: pcie_link_disable_set: lnk_ctrl = 8
>
> So, probably my test environment does not work as expected and I have to
> test it on the failing machine.

I think you probably did reproduce the problem, it's just that it
wasn't fixed by bouncing the link.  What if you try the following:

    DEV=00:0a.0
    setpci -s$DEV BRIDGE_CONTROL.W=0x0040
    sleep 1
    setpci -s$DEV BRIDGE_CONTROL.W=0x0000
    sleep 1
    echo 1 > /sys/bus/pci/rescan

Thanks to your patch, we reconfigured the secondary bus number of
bridge 00:0a.0.  The commands above should reset the FC device behind
that bridge.  I suspect it will then respond when we rescan that bus.

Bjorn