From: Christoph Lameter <christoph@lameter.com>
To: linux-ia64@vger.kernel.org
Subject: Re: Real time clock on ia64 platforms
Date: Tue, 01 Jun 2004 17:22:22 +0000 [thread overview]
Message-ID: <Pine.LNX.4.58.0406011018460.23039@server.home> (raw)
In-Reply-To: <40BC3558.7040606@hob.de>
The portable way to access the RTC is either gettimeofday()
or clock_gettime(CLOCK_REALTIME). The gettimeofday caall is a fast system
call on many ia64 platforms and does not use EFI calls. EFI calls are only
used on bootup to determine the current RTC clock and the clock characteristics.
On Tue, 1 Jun 2004, Alex Williamson wrote:
> On Tue, 2004-06-01 at 01:50, Christian Hildner wrote:
> > Hi,
> >
> > someone may know what kind of RTC device the ia64 platforms (HP ZX 6000
> > + i2000) use. I want to access it directly, without using EFI calls.
>
> This is strongly not recommended. On HP chipset boxes, the devices
> are only designed to be accessed via the EFI calls (and yes, EFI
> firmware can and does work around bugs in the RTC). There's also no
> architected way to find the real RTC in the address map. Why do you
> need to poke it directly?
>
> Alex
>
> -
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>
next prev parent reply other threads:[~2004-06-01 17:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-01 7:50 Real time clock on ia64 platforms Christian Hildner
2004-06-01 16:21 ` Matthew Wilcox
2004-06-01 16:40 ` Alex Williamson
2004-06-01 17:22 ` Christoph Lameter [this message]
2004-06-02 5:56 ` Christian Hildner
2004-06-02 6:04 ` Stephane Eranian
2004-06-02 6:26 ` Christian Hildner
2004-06-02 6:41 ` Christian Hildner
2004-06-02 6:51 ` Stephane Eranian
2004-06-02 7:01 ` Christian Hildner
2004-06-02 7:14 ` Stephane Eranian
2004-06-02 7:22 ` Robin Holt
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