From: Vojtech Pavlik <vojtech@suse.cz>
To: Andi Kleen <ak@suse.de>
Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
john stultz <johnstul@us.ibm.com>,
lkml <linux-kernel@vger.kernel.org>,
keith maanthey <kmannth@us.ibm.com>,
Max Asbock <masbock@us.ibm.com>, Chris McDermott <lcm@us.ibm.com>
Subject: Re: i386 HPET code
Date: Fri, 4 Feb 2005 21:03:59 +0100 [thread overview]
Message-ID: <20050204200359.GA5569@ucw.cz> (raw)
In-Reply-To: <20050204200238.GA5510@ucw.cz>
On Fri, Feb 04, 2005 at 09:02:38PM +0100, Vojtech Pavlik wrote:
> On Thu, Feb 03, 2005 at 10:30:26PM +0100, Andi Kleen wrote:
> > On Thu, Feb 03, 2005 at 06:28:27AM -0800, Pallipadi, Venkatesh wrote:
> > >
> > > Hi John, Andrew,
> > >
> > >
> > > Can you check whether only the following change makes the problem go
> > > away. If yes, then it looks like a hardware issue.
> > >
> > > > hpet_writel(hpet_tick, HPET_T0_CMP);
> > > >+ hpet_writel(hpet_tick, HPET_T0_CMP); /* AK: why twice? */
> >
> >
> > Ask Vojtech (cced), he wrote the x86-64 HPET code.
>
> It took me a while to remember, but:
>
> The first write after writing TN_SETVAL to the config register sets the
> counter value, the second write sets the threshold.
>
> When you only do the first write you never set the threshold and
> interrupts won't be generated properly.
That means it's not a bug, but a (documented) feature.
--
Vojtech Pavlik
SuSE Labs, SuSE CR
next prev parent reply other threads:[~2005-02-04 20:10 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-03 14:28 i386 HPET code Pallipadi, Venkatesh
2005-02-03 19:30 ` john stultz
2005-02-03 20:02 ` Venkatesh Pallipadi
2005-02-03 21:22 ` Andi Kleen
2005-02-04 17:22 ` Andrew Walrond
2005-02-03 21:30 ` Andi Kleen
2005-02-04 19:28 ` Vojtech Pavlik
2005-02-04 20:02 ` Vojtech Pavlik
2005-02-04 20:03 ` Vojtech Pavlik [this message]
2005-02-04 23:41 ` [PATCH][i386] HPET setup, duplicate HPET_T0_CMP needed for some platforms Venkatesh Pallipadi
2005-02-05 10:55 ` Andrew Walrond
2005-02-06 15:58 ` Giuseppe Bilotta
-- strict thread matches above, loose matches on Subject: below --
2005-02-03 2:05 i386 HPET code john stultz
2005-02-03 8:37 ` Andrew Walrond
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