# Found PM-Timer Bug on the chipset. Due to workarounds for...

## sigra

dmesg shows me this:

* Found PM-Timer Bug on the chipset. Due to workarounds for a bug,

* this clock source is slow. Consider trying other clock sources

What should I do about it?

----------

## synapscape

Hi!

Found this on the net a while ago as i was wondering about the same "problem":

 *Quote:*   

> This basically means that your chipset has a bug which requires the ACPI PM timer to be read three times in order to get a valid reading.
> 
> This will cause gettimeofday/clock_gettime to take longer to execute, which is what is meant by "slow" (rather then the counter's frequency being incorrect).

 

So, you don't have a real problem, it's just that reading the clocksource requires more time than it should. Unless you are running some sw which repeatedly reads the time, you will not experience any quirks on your system, i.e. this is not the source for errors related to a strong clock drift. These problems arise from somewhere else.

If the message annoys you, you can try to select a different clocksource with the "clocksource=" kernel parameter, just add it to your grub/lilo conf. See /usr/src/linux/Documentation/kernel-parameters.txt for details. I would try with "clocksource=tsc" first.

Good Luck!

Markus

----------

## sigra

 *synapscape wrote:*   

> If the message annoys you, you can try to select a different clocksource with the "clocksource=" kernel parameter, just add it to your grub/lilo conf. See /usr/src/linux/Documentation/kernel-parameters.txt for details. I would try with "clocksource=tsc" first.

 

Unfortunately this does not seem to help:

# dmesg|egrep --line-number "PM-Timer|clock"

31:ACPI: PM-Timer IO Port: 0x4008

34:Kernel command line: root=/dev/hda4 clocksource=tsc video=uvesafb:1280x1024-24,mtrr:3,ywrap,maxhf:96,maxvf:160,maxclk:202.5

79:* Found PM-Timer Bug on the chipset. Due to workarounds for a bug,

80:* this clock source is slow. Consider trying other clock sources

96:Time: tsc clocksource has been installed.

----------

## bunder

not sure if any of these help at all...

disable_timer_pin_1 noapic acpi=noirq no_irq_poll

i have the same error on one of my machines, but it doesn't seem to cause any problems...  the aforementioned machine won't boot properly without those messages.

cheers

----------

## Monkeh

 *sigra wrote:*   

>  *synapscape wrote:*   If the message annoys you, you can try to select a different clocksource with the "clocksource=" kernel parameter, just add it to your grub/lilo conf. See /usr/src/linux/Documentation/kernel-parameters.txt for details. I would try with "clocksource=tsc" first. 
> 
> Unfortunately this does not seem to help:
> 
> # dmesg|egrep --line-number "PM-Timer|clock"
> ...

 

It's a warning. It's going to give it to you no matter what clocksource you pick.

----------

