From: Borislav Petkov <bp@alien8.de>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: tony.luck@intel.com, gong.chen@linux.intel.com,
ananth@in.ibm.com, masbock@linux.vnet.ibm.com, x86@kernel.org,
linux-kernel@vger.kernel.org, bp@amd64.org, lcm@us.ibm.com,
andi@firstfloor.org, hpa@zytor.com, tglx@linutronix.de,
mingo@redhat.com, gregkh@suse.de, linux-edac@vger.kernel.org
Subject: Re: [PATCH v3] x86/mce: Honour bios-set CMCI threshold
Date: Wed, 17 Oct 2012 15:09:34 +0200 [thread overview]
Message-ID: <20121017130934.GB14590@x1.osrc.amd.com> (raw)
In-Reply-To: <507E9622.6090606@linux.vnet.ibm.com>
On Wed, Oct 17, 2012 at 04:57:30PM +0530, Naveen N. Rao wrote:
> On 10/17/2012 04:29 PM, Borislav Petkov wrote:
> >>>
> >>>+static struct dev_ext_attribute dev_attr_bios_cmci_threshold = {
> >>>+ __ATTR(bios_cmci_threshold, 0444, device_show_int, NULL),
> >>>+ &mce_bios_cmci_threshold
> >
> >Ok, I just noticed this (we must've missed it during review) but why is
> >this read-only? If it has to be read-only, why do we have a node for
> >this in sysfs instead of simply issuing the printk statements below and
> >people who are interested in this, can grep dmesg?
>
> This was added so that user-space tools could find out if we're
> using thresholds for CMCI.
That I figured out.
What I can't figure out is why userspace tools need to know that - the
fact that some MCI_CTL2 has a 0 CMCI threshold because BIOS forgot to
set it correctly? IOW, this is a rather evolved workaround for b0rked
BIOS (the gazillionth BIOS f*ckup, btw if someone is counting :)) and,
on top of that, we have a read-only, special sysfs node which is pretty
useless to me.
Why?
--
Regards/Gruss,
Boris.
next prev parent reply other threads:[~2012-10-17 13:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-11 5:31 [PATCH v2] x86/mce: Honour bios-set CMCI threshold Naveen N. Rao
2012-09-11 16:04 ` Tony Luck
2012-09-12 12:25 ` [PATCH v3] " Naveen N. Rao
2012-09-21 11:39 ` Naveen N. Rao
2012-10-17 10:59 ` Borislav Petkov
2012-10-17 11:27 ` Naveen N. Rao
2012-10-17 13:09 ` Borislav Petkov [this message]
2012-10-17 15:47 ` Naveen N. Rao
2012-10-17 16:40 ` Borislav Petkov
2012-10-17 17:28 ` Luck, Tony
2012-10-17 18:09 ` Borislav Petkov
2012-10-18 5:43 ` Naveen N. Rao
2012-10-18 13:24 ` Borislav Petkov
2012-10-18 16:46 ` Luck, Tony
2012-10-19 15:52 ` [tip:x86/urgent] x86, MCE: Remove bios_cmci_threshold sysfs attribute tip-bot for Borislav Petkov
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