Re: [E1000-devel] 82571EB: Detected Hardware Unit Hang

Joe,
    Possibly your customer is running a kernel without source code on
a platform whose vendor wouldn't like to fix BIOS issue( Is that a
HP/Dell server ?).
    Anyway, to see if is a payload issue or,  you could change the
payload size with setpci tool to those devices and set the link
retrain bit to trigger the link retraining to debug the issue and
identity the root cause.  I thinks it is much easier than modify the
BIOS or  eeprom of NIC.

    e.g.
   set device control register to 0f 00   (128 bytes payload size)
   #   setpci -v -s 00:02.0 98.w=000f
   set device link control register to 60h (retrain the link)
   #  setpci -v -s 00:02.0 a0.b=60

  Hope it works,  Just my 2 cents.

Ethan.zhao@oracle.com

On Wed, Nov 28, 2012 at 11:53 PM, Fujinaka, Todd
[off-list ref] wrote:

The only EEPROM I know about or can speak to is the one attached to the 82571 and it doesn't set the MaxPayloadSize. That's done by the BIOS.

Todd Fujinaka
Technical Marketing Engineer
LAN Access Division (LAD)
Intel Corporation
todd.fujinaka@intel.com
(503) 712-4565


-----Original Message-----
From: Joe Jin [mailto:joe.jin@oracle.com]
Sent: Wednesday, November 28, 2012 12:31 AM
To: Ben Hutchings
Cc: Fujinaka, Todd; Mary Mcgrath; netdev@vger.kernel.org; e1000-devel@lists.sf.net; linux-kernel@vger.kernel.org; linux-pci
Subject: Re: [E1000-devel] 82571EB: Detected Hardware Unit Hang

On 11/28/12 02:10, Ben Hutchings wrote:

quoted

On Tue, 2012-11-27 at 17:32 +0000, Fujinaka, Todd wrote:

quoted

Forgive me if I'm being too repetitious as I think some of this has
been mentioned in the past.

We (and by we I mean the Ethernet part and driver) can only change
the advertised availability of a larger MaxPayloadSize. The size is
negotiated by both sides of the link when the link is established.
The driver should not change the size of the link as it would be
poking at registers outside of its scope and is controlled by the
upstream bridge (not us).

[...]

MaxPayloadSize (MPS) is not negotiated between devices but is
programmed by the system firmware (at least for devices present at
boot - the kernel may be responsible in case of hotplug).  You can use
the kernel parameter 'pci=pcie_bus_perf' (or one of several others) to
set a policy that overrides this, but no policy will allow setting MPS
above the device's MaxPayloadSizeSupported (MPSS).

Ben,

Unfortunately I'm using 3.0.x kernel and this is not included in the kernel.
So I'm trying to use ethtool modify it from eeprom to see if help or no.


Todd, I'll review all MaxPayload for all devices, but need to say if it mismatch, customer could not modify it from BIOS for there was not entry at there, to test it, we have to find how to verify if this is the root cause, so still need to find the offset in eeprom.

Thanks in advance,
Joe