hpet on nforce4/MCP51 in asus a6t

hpet on nforce4/MCP51 in asus a6t

[f.cecco77]

Hello,
I have  a asus a6t with nforce4/MCP51 chipset. I pass to kernel 2.6.24 
32 bit the options acpi_use_timer_override and hpet=force, in this way 
and the timer IRQ ends up routed as  IO-APIC-edge instead of XT-PIC. 
With acpi_use_timer_override I just get:

TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1

and it works through the IO-APIC. 

Instead the hpet is disabled and I  just get :

Time: acpi_pm clocksource has been installed.
Clocksource tsc unstable (delta = -85010975 ns)

Is possible to have hpet working also with if the BIOS doesn't support 
it ?

I wish to be personally CC'ed the answers/comments posted to the list 
in response to my posting.

Cecco






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Re: hpet on nforce4/MCP51 in asus a6t

[Carlos Corbacho]

[Adding tglx to CC as he knows more about HPET's than I]

On Sunday 03 February 2008 18:33:57 f.cecco77@tiscali.it wrote:
> Hello,
> I have  a asus a6t with nforce4/MCP51 chipset. I pass to kernel 2.6.24
> 32 bit the options acpi_use_timer_override and hpet=force, in this way
> and the timer IRQ ends up routed as  IO-APIC-edge instead of XT-PIC.
> With acpi_use_timer_override I just get:
>
> TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
>
> and it works through the IO-APIC.
>
> Instead the hpet is disabled and I  just get :
>
> Time: acpi_pm clocksource has been installed.
> Clocksource tsc unstable (delta = -85010975 ns)
>
> Is possible to have hpet working also with if the BIOS doesn't support
> it ?

One point before we start - MCP51 is nForce 5, not nForce 4 (which is CK804).

If my understanding is correct, acpi_use_timer_override is only a workaround 
required for those nForce 5 boards that don't enable the HPET for you.

So IIUC, you should be able to use either 'hpet=force' 
or 'acpi_use_timer_override', either of which should solve any timing issues 
you see, but you shouldn't need both (which should solve your problem of 
acpi_use_timer_override ignoring the HPET - it shouldn't be needed 
if 'hpet=force' enables the HPET).

-Carlos
-- 
E-Mail: carlos@strangeworlds.co.uk
Web: strangeworlds.co.uk
GPG Key ID: 0x23EE722D

Re: hpet on nforce4/MCP51 in asus a6t

[cecco]

Carlos Corbacho <carlos <at> strangeworlds.co.uk> writes:

> 
> [Adding tglx to CC as he knows more about HPET's than I]
> 
> On Sunday 03 February 2008 18:33:57 f.cecco77 <at> tiscali.it wrote:
> > Hello,
> > I have  a asus a6t with nforce4/MCP51 chipset. I pass to kernel 2.6.24
> > 32 bit the options acpi_use_timer_override and hpet=force, in this way
> > and the timer IRQ ends up routed as  IO-APIC-edge instead of XT-PIC.
> > With acpi_use_timer_override I just get:
> >
> > TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> >
> > and it works through the IO-APIC.
> >
> > Instead the hpet is disabled and I  just get :
> >
> > Time: acpi_pm clocksource has been installed.
> > Clocksource tsc unstable (delta = -85010975 ns)
> >
> > Is possible to have hpet working also with if the BIOS doesn't support
> > it ?
> 
> One point before we start - MCP51 is nForce 5, not nForce 4 (which is CK804).
> 
> If my understanding is correct, acpi_use_timer_override is only a workaround 
> required for those nForce 5 boards that don't enable the HPET for you.
> 
> So IIUC, you should be able to use either 'hpet=force' 
> or 'acpi_use_timer_override', either of which should solve any timing issues 
> you see, but you shouldn't need both (which should solve your problem of 
> acpi_use_timer_override ignoring the HPET - it shouldn't be needed 
> if 'hpet=force' enables the HPET).
> 
> -Carlos

Thanks for your answer. In my case only acpi_use_timer_override helps with
timing issues, enabling apic. Unfortunately,  either the options hpet=force or 
acpi_use_timer_override  don't enable HPET on asus a6t. The situation is always
the same:

cecco:/home/cecco# grep Clock /proc/timer_list
Clock Event Device: pit
Clock Event Device: lapic
Clock Event Device: lapic

I don't understand because with Turion X2 or amd64 is so difficult to have hpet
and dynticks working. Is important to have a cool notebook, but Amd doesn't seem
 to understand it. Amd has introduced C1e state for a good powersaving, saying
it is equivalent to C3 state but I haven't any prove about this.

Cecco