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 21:02:38 +0100 [thread overview]
Message-ID: <20050204200238.GA5510@ucw.cz> (raw)
In-Reply-To: <20050203213026.GF3181@wotan.suse.de>
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.
--
Vojtech Pavlik
SuSE Labs, SuSE CR
next prev parent reply other threads:[~2005-02-04 20:12 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 [this message]
2005-02-04 20:03 ` Vojtech Pavlik
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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