From: Samuel Ortiz <sameo@linux.intel.com>
To: Feng Tang <feng.tang@intel.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>,
Wim Van Sebroeck <wim@iguana.be>, Len Brown <len.brown@intel.com>,
linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
Aaron Sierra <asierra@xes-inc.com>,
Bob Moore <robert.moore@intel.com>,
Guenter Roeck <linux@roeck-us.net>,
rui.zhang@intel.com
Subject: Re: [PATCH] lpc_ich: Fix a 3.5 kernel regression for iTCO_wdt driver
Date: Thu, 23 Aug 2012 19:13:15 +0200 [thread overview]
Message-ID: <20120823171315.GD9889@sortiz-mobl> (raw)
In-Reply-To: <20120823130814.6ba359e9@feng-i7>
Hi Feng,
On Thu, Aug 23, 2012 at 01:08:14PM +0800, Feng Tang wrote:
> On Wed, 22 Aug 2012 22:55:43 +0100
> Matthew Garrett <mjg59@srcf.ucam.org> wrote:
>
> > On Wed, Aug 22, 2012 at 09:55:12PM +0200, Wim Van Sebroeck wrote:
> >
> > > Any idea why the acpi_check_resource_conflict() check gives a conflict?
> >
> > Because the resource range is declared in ACPI and we assume that that
> > means the firmware wants to scribble on it. We'd need the output of
> > acpidump to work out whether that's safe or not.
>
> Good point, I checked the conflict for iTCO_wdt, the conflict exists on
> almost all the machines I have.
>
> According to ICH (7/8/9 etc)spec, the TCO watchdog has a 32 bytes long IO
> space resource, and the bit 9 of TCO1_STS register is "DMISCI_STS", which
> indicates whether a SCI happens, and will be cleared by writing 1
> to it. Most of DSDT table will claim a TCO op region only for one bit:
> "DMISCI_STS" , as some method may need to access that bit.
>
> I think there is some risk, but it's quite safe as the DMISCI_STS bit has
> nothing to do with TCO driver itself, and TCO driver never access it, also
> this TCO driver has been there for years, and this resource conflict also
> exists for many generations hardware.
Makes sense to me.
I'm queueing this one to my for-linus branch, I'll send a pull request soon.
Cheers,
Samuel.
--
Intel Open Source Technology Centre
http://oss.intel.com/
next prev parent reply other threads:[~2012-08-23 17:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-14 15:56 [PATCH] lpc_ich: Fix a 3.5 kernel regression for iTCO_wdt driver Feng Tang
2012-08-22 19:55 ` Wim Van Sebroeck
2012-08-22 21:55 ` Matthew Garrett
2012-08-23 5:08 ` Feng Tang
2012-08-23 17:13 ` Samuel Ortiz [this message]
2012-08-23 15:28 ` Guenter Roeck
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