From: John Sigler <linux.kernel@free.fr>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-rt-users@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: Re: High resolution timers on ACPI-less kernel
Date: Tue, 09 Oct 2007 12:35:29 +0200 [thread overview]
Message-ID: <470B5971.40601@free.fr> (raw)
In-Reply-To: <alpine.LFD.0.9999.0710091131400.25146@localhost.localdomain>
Thomas Gleixner wrote:
> On Tue, 9 Oct 2007, John Sigler wrote:
>> Alessio Igor Bogani wrote:
>>> On Tue, 2007-10-09 at 11:06 +0200, John Sigler wrote:
>>>
>>>> I enabled high resolution timer support and disabled ACPI support.
>>>
>>> http://www.mail-archive.com/linux-rt-users@vger.kernel.org/msg00375.html
>>
>> There are other clock sources on my system.
>> The timestamp counter is reliable (as far as I can tell).
>
> See previous mail.
>
>> The LAPIC timer is reliable.
>
> LAPIC timer is a clock event device, not a clock source. It can be
> used to program the next event, but not to read the time.
>
>> (I've just disabled the PM timer.)
>
> Yup, which in turn disables highres.
OK. I have two more questions.
Can the kernel verify the correctness of the TSC with the PIT?
When I enable the ACPI PM timer, the kernel tells me:
* The chipset may have PM-Timer Bug. Due to workarounds for a bug,
* this clock source is slow. If you are sure your timer does not have
* this bug, please use "acpi_pm_good" to disable the workaround
How can I tell whether my PM timer has this bug or not?
(Specific revision? Test app?)
Regards.
next prev parent reply other threads:[~2007-10-09 10:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-09 9:06 High resolution timers on ACPI-less kernel John Sigler
2007-10-09 9:15 ` Alessio Igor Bogani
2007-10-09 9:28 ` John Sigler
2007-10-09 9:34 ` Thomas Gleixner
2007-10-09 10:35 ` John Sigler [this message]
2007-10-09 15:59 ` Dragan Noveski
2007-10-09 17:13 ` Thomas Gleixner
2007-10-11 10:37 ` Dragan Noveski
2007-10-09 9:20 ` John Sigler
2007-10-09 9:22 ` Thomas Gleixner
2007-10-09 9:39 ` John Sigler
2007-10-09 9:48 ` Alessio Igor Bogani
2007-10-09 9:53 ` Thomas Gleixner
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