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From: Alex Williamson <alex.williamson@redhat.com>
To: Keith Busch <keith.busch@intel.com>
Cc: Yijing Wang <wangyijing@huawei.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, Jordan_Hargrave@Dell.com,
	jon.mason@intel.com, Jon Mason <jdmason@kudzu.us>
Subject: Re: [PATCH] PCI: update device mps when doing pci hotplug
Date: Tue, 29 Jul 2014 10:42:58 -0600	[thread overview]
Message-ID: <1406652178.1011.191.camel@ul30vt.home> (raw)
In-Reply-To: <alpine.LRH.2.03.1407291022380.5109@AMR>

On Tue, 2014-07-29 at 10:30 -0600, Keith Busch wrote:
> On Tue, 29 Jul 2014, Alex Williamson wrote:
> > On Tue, 2014-07-29 at 16:17 +0800, Yijing Wang wrote:
> >> Currently we don't update device's mps value when doing
> >> pci device hot-add. The hot-added device's mps will be set
> >> to default value (128B). But the upstream port device's mps
> >> may be larger than 128B which was set by firmware during
> >> system bootup. In this case the new added device may not
> >> work normally.
> >
> > Apologies if we rehash some previously discussed topics while I try to
> > cover for Bjorn while he's out.  By "normally", do you mean "optimally"?
> > The device should be functional with a lower mps setting, right?
> 
> You'd think so, but some platforms don't work. A pci-e trace showed
> TLPs exceeding MPS when parent device at 256B and the end device left
> at 128B. Even if that's a platform bug, I think we still want it to work.

But if it's a platform bug for a non-compliant device, should it be
handled as a quirk rather than standard configuration?  Thanks,

Alex



  reply	other threads:[~2014-07-29 16:43 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-29  8:17 [PATCH] PCI: update device mps when doing pci hotplug Yijing Wang
2014-07-29 16:18 ` Alex Williamson
2014-07-29 16:30   ` Keith Busch
2014-07-29 16:42     ` Alex Williamson [this message]
2014-07-29 19:04       ` Keith Busch
2014-07-30  3:35       ` Yijing Wang
2014-07-30  3:27   ` Yijing Wang
2014-07-30  3:33 ` Ethan Zhao
2014-07-30  3:42   ` Yijing Wang
2014-07-30  3:58     ` Ethan Zhao
2014-07-30  4:42       ` Yijing Wang
2014-07-30  6:26 ` Ethan Zhao
2014-07-30  6:57   ` Yijing Wang
2014-07-30  7:17     ` Ethan Zhao
2014-07-30  8:13       ` Yijing Wang
2014-07-30  8:38         ` Ethan Zhao
2014-07-30  9:17           ` Yijing Wang
2014-07-30 19:41             ` Jordan_Hargrave
2014-09-03 19:20               ` Bjorn Helgaas
2014-09-03 22:42 ` Bjorn Helgaas
2014-09-04  6:12   ` Yijing Wang
2014-09-04 13:16     ` Bjorn Helgaas
2014-09-05  1:27       ` Yijing Wang
2014-09-05 14:37         ` Keith Busch
2014-09-24 22:41         ` Keith Busch
2014-09-24 23:30           ` Bjorn Helgaas
2014-09-25  1:23             ` Yijing Wang
2014-09-25 16:46               ` Keith Busch
2014-09-26  3:22                 ` Yijing Wang
2014-10-02 15:31                   ` Jordan_Hargrave
  -- strict thread matches above, loose matches on Subject: below --
2014-07-29  8:23 Yijing Wang
2013-02-05  3:55 Yijing Wang
2013-05-28  3:15 ` Yijing Wang
2013-07-29 23:33   ` Bjorn Helgaas
2013-07-30  3:20     ` Yijing Wang
2013-07-30  3:42       ` Bjorn Helgaas
2013-07-30 22:29         ` Bjorn Helgaas
2013-07-31  9:15           ` Yijing Wang
2013-07-31 17:53             ` Bjorn Helgaas
2013-07-31 20:42               ` Bjorn Helgaas
2013-08-01  1:23                 ` Yijing Wang
2013-08-01  1:21               ` Yijing Wang

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