Re: 82571EB: Detected Hardware Unit Hang

On Mon, Jul 16, 2012 at 9:08 AM, Henrique de Moraes Holschuh
[off-list ref] wrote:

On Mon, 16 Jul 2012, Ben Hutchings wrote:

quoted

On Sun, 2012-07-15 at 10:35 -0300, Henrique de Moraes Holschuh wrote:

quoted

On Sun, 15 Jul 2012, Dave, Tushar N wrote:

quoted

Somehow setting max payload to 256 from BIOS does not set this value for all devices. I believe this is a BIOS bug.

And preferably, Linux should complain about it.  Since we know it is going
to cause problems, and since we know it does happen, we should be raising a
ruckus about it in the kernel log (and probably fixing it to min(path) while
at it)...

Is this something that should be raised as a feature request with the
PCI/PCIe subsystem?

The feature is there, but we ended up with:

commit 5f39e6705faade2e89d119958a8c51b9b6e2c53c
Author: Jon Mason [off-list ref]
Date:   Mon Oct 3 09:50:20 2011 -0500

    PCI: Disable MPS configuration by default

But you are welcome to share use of the fixup_mpss_256() quirk.

Meh.  I'd be happy with a warning if MPSS decreases when walking up to
the tree root... i.e. a warning if any child has a MPSS larger than the
parent.

You can add "pci=pcie_bus_safe" to the kernel params and it should
resolve your issue.

--
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh
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