Hi all,

    Does anyone know how to disable cpu c state from application or
driver?
    Because we have low performance issue when cpu went to C3 state.
    But in some bios there is no option to disable cpu c state (or c3
state)


Thanks a lot!

On 3=A4=EB15=A4=E9, =A4U=A4=C86=AE=C904=A4=C0, =B3=AF =A6=F6=B9F <yoda.chc.=
...@gmail.com> wrote:
> Hi all,
>
>     Does anyone know how to disable cpu c state from application or
> driver?
>     Because we have low performance issue when cpu went to C3 state.
>     But in some bios there is no option to disable cpu c state (or c3
> state)
>
> Thanks a lot!

    I use following code in XP but it doesn't !

    unsigned int ActPwrSch;
    MACHINE_PROCESSOR_POWER_POLICY Policy;
    if(GetActivePwrScheme(&ActPwrSch))
    {
        if(ReadProcessorPwrScheme(ActPwrSch,&Policy))
        {
            printf("Read Power Scheme:\n");
            if(Policy.ProcessorPolicyAc.DisableCStates!=3D0)
            {
                printf("DisableCStates=3DTRUE\n");
            }
            else
            {
                printf("DisableCStates=3DFalse\n");
            }
            Policy.ProcessorPolicyAc.DisableCStates=3D1;
            if(WriteProcessorPwrScheme(ActPwrSch,&Policy))
            {
                printf("WriteProcessorPwrScheme succeed\n");
                if(SetActivePwrScheme(ActPwrSch,0,0))
                {
                    printf("SetActivePwrScheme succeed!!\n")
                }
            }

        }
    }