From: Keith Busch <keith.busch@intel.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: Alex_Gagniuc@Dellteam.com, linux-pci@vger.kernel.org,
bhelgaas@google.com, Austin.Bolen@dell.com
Subject: Re: PCI: hotplug: Erroneous removal of hotplug PCI devices
Date: Wed, 23 Jan 2019 12:33:15 -0700 [thread overview]
Message-ID: <20190123193314.GA8193@localhost.localdomain> (raw)
In-Reply-To: <20190123191527.sp44r4la5vgln4el@wunner.de>
On Wed, Jan 23, 2019 at 08:15:27PM +0100, Lukas Wunner wrote:
> On Wed, Jan 23, 2019 at 12:07:38PM -0700, Keith Busch wrote:
> > Right, so in Alex's case, it looks like we are observing
> > pcie_wait_for_link() returning true before the PDC event.
> >
> > I'm wondering about PDS because if the link is up but Presence reports an
> > empty slot, does that matter for any implementations? Or is it perfectly
> > fine to enumerate an active link on an empty slot? An empty slot and
> > active link doesn't make a lot of sense, but that observation appears to
> > be what is reported here.
>
> We allow enumeration with an active link of an allegedly empty slot
> because some hardware hardwires PDS to zero, see commit 80696f991424
> ("PCI: pciehp: Tolerate Presence Detect hardwired to zero").
>
> The brokenness of PCIe hotplug implementations found in the wild is
> astonishing.
Heh, sounds like Alex's proposal may work until we find a slot
implementation that doesn't do DLLSC as expected. :)
next prev parent reply other threads:[~2019-01-23 19:34 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-23 18:20 PCI: hotplug: Erroneous removal of hotplug PCI devices Alex_Gagniuc
2019-01-23 18:44 ` Keith Busch
2019-01-23 19:02 ` Lukas Wunner
2019-01-23 19:07 ` Keith Busch
2019-01-23 19:15 ` Lukas Wunner
2019-01-23 19:33 ` Keith Busch [this message]
2019-01-24 22:43 ` Austin.Bolen
2019-01-24 22:52 ` Austin.Bolen
[not found] ` <b32e6ca62ae2494f98450df81ca1ee14@AUSX13MPC131.AMER.DELL.COM>
2019-01-24 20:20 ` Keith Busch
2019-01-24 22:00 ` Austin.Bolen
2019-01-25 8:22 ` Lukas Wunner
2019-01-25 22:39 ` Austin.Bolen
2019-01-26 12:12 ` Lukas Wunner
2019-01-30 14:28 ` Austin.Bolen
2019-01-23 18:54 ` Lukas Wunner
2019-01-23 19:07 ` Lukas Wunner
2019-01-23 19:09 ` Keith Busch
2019-01-23 19:28 ` Lukas Wunner
2019-01-23 19:47 ` Keith Busch
2019-01-23 20:10 ` Alex_Gagniuc
2019-01-23 23:50 ` Alex_Gagniuc
2019-01-24 9:25 ` Lukas Wunner
2019-01-24 22:33 ` Austin.Bolen
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