[MinnowBoard] MinnowBoard MAX 0.93 64-Bit & network lost

Krau, Michael P michael.p.krau at intel.com
Thu Sep 8 00:18:09 UTC 2016

I notice that the 0.93 MinnowBoard MAX has the following changes (per the release notes):

6. Main changes in this release
   1) Enabled PCIe port 1; 
   3) Enabled Spread Spectrum of several devices; 

Personally I am always concerned when clocking gets changed in a system (i.e. note #3), and in this case it may be mild paranoia on my part.  Though if the failure is intermittent, it could be related to a the spread spectrum change.  My experience has been when manipulating clock frequencies in a system, if it results in creating an issue, the issue tends to be asynchronous and variable: Either happens only 1 out of every n (n possibly being variable as well) runs, or happens in a wildly variable time frame (takes as little as 2 seconds and as long as 12 hours) to failure, regardless of environmental issues.  Especially when the hardware is not the same as the initial target of the firmware (propagation and signal time deltas can make the timing changes more impactful on different hardware).

But also note #1, enabling the PCIe port 1, could this contribute to PCIe disconnects in the custom hardware? 


Michael Krau
-----Original Message-----
From: elinux-MinnowBoard [mailto:elinux-minnowboard-bounces at lists.elinux.org] On Behalf Of David Scully
Sent: Wednesday, September 07, 2016 4:19 PM
To: elinux-minnowboard at lists.elinux.org
Subject: Re: [MinnowBoard] MinnowBoard MAX 0.93 64-Bit & network lost


I was able to do a bit more testing today comparing our board to the Minnowboard Max.

With 0.93 firmware on the Minnowboard Max (8111gs) I was unable to reproduce this issue running 16.04. 

I actually have a second drive loaded with Ubuntu 14.04 (which uses kernel
3.16) and was able reproduce on our custom board using the iperf tests. So I'm not sure you'd be more likely to see this under a newer kernel. Whether it becomes more common is unclear -- I had to run my test for a bit longer
(30 min test) on 14.04 before the disconnect message.

I'm a bit worried that this is a HW problem on our end, but it's still odd to me that 0.92 works without PCIe disconnects.

It would be nice to see Abdelghani's dmesg when the connection fails to see if we're running into similar problems. Unlike Abdelghani, when the NIC disconnects the only way I'm able to save it is a full reboot. Perhaps the 8111gs driver is better at recovering from this condition or he isn't seeing PCIe disconnects at all?

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