linux-kernel - Re: [PATCH] rtc: Disable EFI rtc for x86

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Date:	Tue, 11 Nov 2014 12:53:09 +0100
From:	Pali Rohár <pali.rohar@...il.com>
To:	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Austin S Hemmelgarn <ahferroin7@...il.com>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Matt Fleming <matt.fleming@...el.com>,
	Borislav Petkov <bp@...en8.de>,
	Mark Salter <msalter@...hat.com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	rtc-linux@...glegroups.com, linux-efi@...r.kernel.org,
	linux-kernel@...r.kernel.org, Dave Young <dyoung@...hat.com>
Subject: Re: [PATCH] rtc: Disable EFI rtc for x86

On Tuesday 11 November 2014 12:38:31 One Thousand Gnomes wrote:
> > > look further into the options I have set in my kernel
> > > build, I may have changed something else without
> > > remembering between booting with and without the CSM
> > > enabled.
> > 
> > It could also be that the non-CSM BIOS somehow remaps the
> > CMOS registers.
> 
> I don't believe there is anything which prevents the CSM from
> faking a CMOS clock using SMM from whatever is actually in
> the hardware.
> 
> Alan

Also in case when we do not know what SMM code is doing...

-- 
Pali Rohár
pali.rohar@...il.com

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