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From: Andi Kleen <andi@firstfloor.org>
To: Tony Luck <tony.luck@intel.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
	Mauro Carvalho Chehab <mchehab@redhat.com>,
	"Young, Brent" <brent.young@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Borislav Petkov <bp@amd64.org>, Andi Kleen <andi@firstfloor.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Doug Thompson <dougthompson@xmission.com>,
	Joe Perches <joe@perches.com>, Ingo Molnar <mingo@elte.hu>,
	Matt Domsch <Matt_Domsch@dell.com>,
	Ingo Molnar <mingo@redhat.com>,
	"bluesmoke-devel@lists.sourceforge.net"
	<bluesmoke-devel@lists.sourceforge.net>,
	Linux Edac Mailing List <linux-edac@vger.kernel.org>
Subject: Re: Hardware Error Kernel Mini-Summit
Date: Tue, 15 Jun 2010 08:44:19 +0200	[thread overview]
Message-ID: <20100615064419.GA6727@basil.fritz.box> (raw)
In-Reply-To: <AANLkTil_mDFOsDUjvnp_NFZvkj0Ij-qww6BqewJ4lpHP@mail.gmail.com>

> There was a case mentioned at the collaboration summit
> meeting where a BIOS bug mis-reported whether ECC was
> enabled - claiming it was on, when in fact it was off.

Yes I heard about that, but since it's not a single bit setting
there are lots of different ways it could be broken in theory.

To check it you really need to have a tool that knows about
all the registers and checks them all.

It's a bit like checking if someone speaks a foreign language
by asking them a single question with a one letter answer.

> of the chipset specific code against each other. An EDAC
> driver that tells you that ECC is enabled might be lying too,
> if it is looking at the wrong bit or the wrong register.

Yep.

It's asking a question with a one word answer where you don't
know the correct answer.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

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WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <andi@firstfloor.org>
To: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Nils Carlson <nils.carlson@ludd.ltu.se>,
	Ingo Molnar <mingo@elte.hu>, Borislav Petkov <bp@amd64.org>,
	Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
	Mauro Carvalho Chehab <mchehab@redhat.com>,
	"Young, Brent" <brent.young@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"bluesmoke-devel@lists.sourceforge.net" 
	<bluesmoke-devel@lists.sourceforge.net>,
	Doug Thompson <dougthompson@xmission.com>,
	Joe Perches <joe@perches.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux Edac Mailing List <linux-edac@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Matt Domsch <Matt_Domsch@dell.com>
Subject: Re: Hardware Error Kernel Mini-Summit
Date: Tue, 15 Jun 2010 08:44:19 +0200	[thread overview]
Message-ID: <20100615064419.GA6727@basil.fritz.box> (raw)
In-Reply-To: <AANLkTil_mDFOsDUjvnp_NFZvkj0Ij-qww6BqewJ4lpHP@mail.gmail.com>

> There was a case mentioned at the collaboration summit
> meeting where a BIOS bug mis-reported whether ECC was
> enabled - claiming it was on, when in fact it was off.

Yes I heard about that, but since it's not a single bit setting
there are lots of different ways it could be broken in theory.

To check it you really need to have a tool that knows about
all the registers and checks them all.

It's a bit like checking if someone speaks a foreign language
by asking them a single question with a one letter answer.

> of the chipset specific code against each other. An EDAC
> driver that tells you that ECC is enabled might be lying too,
> if it is looking at the wrong bit or the wrong register.

Yep.

It's asking a question with a one word answer where you don't
know the correct answer.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

  parent reply	other threads:[~2010-06-15  6:44 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-17 18:23 Hardware Error Kernel Mini-Summit Mauro Carvalho Chehab
2010-05-17 22:41 ` Andi Kleen
2010-05-18 16:50   ` Mauro Carvalho Chehab
2010-05-18 18:10     ` Andi Kleen
2010-05-18 18:10       ` Andi Kleen
2010-05-18  6:52 ` Hidetoshi Seto
2010-05-18  6:52   ` Hidetoshi Seto
2010-05-18 16:44   ` Mauro Carvalho Chehab
2010-05-18 16:44     ` Mauro Carvalho Chehab
2010-05-18 17:42     ` Joe Perches
2010-05-18 17:59       ` Mauro Carvalho Chehab
2010-05-18 18:45       ` Andi Kleen
2010-05-18 18:57         ` Joe Perches
2010-05-18 18:53       ` Ingo Molnar
2010-05-18 19:08         ` Luck, Tony
2010-05-18 19:18           ` Borislav Petkov
2010-05-18 19:34             ` Ingo Molnar
2010-05-18 22:14             ` Eric W. Biederman
2010-05-18 22:14               ` Eric W. Biederman
2010-05-18 22:28               ` Andi Kleen
2010-05-19  1:14                 ` Eric W. Biederman
2010-05-19  1:14                   ` Eric W. Biederman
2010-05-19  6:46                   ` Borislav Petkov
2010-05-19  7:09                     ` Ingo Molnar
2010-05-19 11:54                       ` Mauro Carvalho Chehab
2010-05-19 11:54                         ` Mauro Carvalho Chehab
2010-05-20 12:37                         ` Ingo Molnar
2010-06-14 10:03                       ` Nils Carlson
2010-06-14 10:03                         ` Nils Carlson
2010-06-14 11:49                         ` Andi Kleen
2010-06-14 19:47                           ` Nils Carlson
2010-06-14 19:47                             ` Nils Carlson
2010-06-14 20:21                             ` Andi Kleen
2010-06-14 21:02                               ` Nils Carlson
2010-06-14 20:06                           ` Eric W. Biederman
2010-06-14 20:06                             ` Eric W. Biederman
2010-06-14 20:21                             ` Luck, Tony
2010-06-14 20:36                             ` Andi Kleen
2010-06-14 20:36                               ` Andi Kleen
2010-06-14 21:34                               ` Tony Luck
2010-06-14 21:34                                 ` Tony Luck
2010-06-14 23:46                                 ` Doug Thompson
2010-06-15  6:56                                   ` Andi Kleen
2010-06-15  8:06                                     ` Nils Carlson
2010-06-15  8:06                                       ` Nils Carlson
2010-06-15 10:01                                       ` Borislav Petkov
2010-06-15 11:41                                       ` Andi Kleen
2010-06-15 11:41                                         ` Andi Kleen
2010-06-15 12:21                                         ` Nils Carlson
2010-06-15 18:15                                           ` Luck, Tony
2010-06-15 18:38                                             ` Nils Carlson
2010-06-15 18:38                                               ` Nils Carlson
2010-06-15 19:37                                             ` Andi Kleen
2010-06-15 19:37                                               ` Andi Kleen
2010-06-15 19:35                                           ` Andi Kleen
2010-06-15 20:48                                             ` Nils Carlson
2010-06-15 20:48                                               ` Nils Carlson
2010-06-16  9:40                                               ` Andi Kleen
2010-06-16  9:40                                                 ` Andi Kleen
2010-06-15 22:33                                     ` Tony Luck
2010-06-15  6:44                                 ` Andi Kleen [this message]
2010-06-15  6:44                                   ` Andi Kleen
2010-05-19  9:03                   ` Andi Kleen
2010-05-24 16:21                     ` Russ Anderson
2010-05-24 18:26                       ` Andi Kleen
2010-05-24 18:26                         ` Andi Kleen
2010-05-19 17:30                   ` Tony Luck
2010-05-24 15:55                     ` Russ Anderson
2010-05-24 17:35                       ` Tony Luck
2010-05-24 18:31                         ` Andi Kleen
2010-05-18 22:29               ` Ingo Molnar
2010-05-18 19:30           ` Ingo Molnar
2010-05-18 20:42             ` Ingo Molnar
2010-05-18 21:37               ` Tony Luck
2010-05-18 22:00                 ` Ingo Molnar
2010-05-24 17:13                   ` Russ Anderson
2010-05-19  6:39                 ` Ingo Molnar
2010-05-18 13:06 ` Borislav Petkov
2010-05-18 16:52   ` Mauro Carvalho Chehab
2010-05-18 16:52     ` Mauro Carvalho Chehab
2010-05-18 17:06 ` Mauro Carvalho Chehab
2010-05-18 17:06   ` Mauro Carvalho Chehab
  -- strict thread matches above, loose matches on Subject: below --
2010-06-16  8:57 George Spelvin

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