linux-kernel - Re: [PATCH 3/3] ie31200

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Date:	Tue, 08 Apr 2014 23:03:08 -0400
From:	Jason Baron <jbaron@...mai.com>
To:	"Luck, Tony" <tony.luck@...el.com>, Borislav Petkov <bp@...en8.de>
CC:	"hpa@...or.com" <hpa@...or.com>,
	"mingo@...nel.org" <mingo@...nel.org>,
	"dougthompson@...ssion.com" <dougthompson@...ssion.com>,
	"m.chehab@...sung.com" <m.chehab@...sung.com>,
	"mitake@....info.waseda.ac.jp" <mitake@....info.waseda.ac.jp>,
	"linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] ie31200_edac: Add driver

On 04/08/2014 06:34 PM, Luck, Tony wrote:
>>> Btw, this driver is polling, AFAICT. Doesn't e3-12xx support the CMCI
>>> interrupt which you can feed into this driver directly and thus not need
>>> the polling at all?
>> On the system with the ce and ue events that I'm testing on, I don't see
>> 'MCE' nudge above 0, in /proc/interrupts. So I think that implies that
>> we are not getting any CMCI there?
> CMCI will bump up the "THR" (Threshold) entries in /proc/interrupts.

Ok, so on the system with ue and ce events (as reported by driver
and confirmed with a memory scanner), "THR" is 0 across
all cpus, and I see no machine checks in the logs...

>> So if possible maybe we can confirm with Intel whether we expect an MCE
>> for memory errors...
> MCG_CAP bit 10 tells you whether a given processor implements CMCI.
> If that is set - then MCi_CTL2 bit 30 indicates whether a given bank
> supports it (Linux tries to set this bit, if it sticks, then it knows that CMCI
> is supported - Linux also assigns ownership of the bank to the first cpu
> to successfully set it (since a bank may be shared by multiple threads/cores
> on a package).
>
> Consumed uncorrectable errors should generate a machine check. Which
> on the E3-12xx series will be a fatal machine check: MCi_STATUS.PCC=1
>
> -Tony
>

Hmmm...as I said, I'm not getting any machine checks with ue errors. I've
got a fairly old kernel on the system atm, I will try loading a newer kernel,
to see if that makes any difference...

Thanks,

-Jason

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