Re: _CST Patches

Bruno Ducrot
2005-04-18T14:26:19Z

On Mon, Apr 18, 2005 at 02:16:25PM +0200, Janosch Machowinski wrote:
>
> > > This patch fakes an C1 state if the given states by the _CST object
> > > start with anything else than C1 (like on my M6NE here it start's with
> > > C2)
> >
> > It should not be needed. I've taken care that it work by testing
> > in almost all cases by overriding the DSDT when I wrote this part to
> > handle properly almost all cases (I forgot the case when C1 and C3, but
> > no C2 though, that why I wrote 'almost').
> >
> > Normally, we register a C1 state no matter what before we check
> > the content of _CST, then we just skip if a C1 type is found.
> >
> > If your patch is needed, then the patch I send some times ago have not been
> > fully integrated in the original form, or maybe the wrong one was considered
> > (the first was buggy in that regard, but the second was OK).
> >
> Your first patch has been modified, and now my patch is needed.
> In your first implementation you did an (pr->power)++ before the loop
> that started the polling of the _CST object.

Since C1 is not handled by the loop itself, it is needed to count it
before the loop.

> At the moment all C-States
> are deleted (see the memset) and generated from scratch.

I see... Sound like it has been modified. I don't know why.

> Your idea
> sounds faster to me !
>
>
> > I would prefer
> > memset(pr->power.states, 0, ACPI_PROCESSOR_MAX_POWER * sizeof(struct acpi_processor_cx));
> > (without the loop)
>
> I agree, looks faster to me.
>
> A new patch is attached
>
> Janosch

> --- processor_idle.original 2005-04-16 17:13:44.000000000 +0200
> +++ processor_idle.c 2005-04-18 14:13:52.000000000 +0200
> @@ -479,8 +479,6 @@
>
> static int acpi_processor_get_power_info_fadt (struct acpi_processor *pr)
> {
> - int i;
> -
> ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
>
> if (!pr)
> @@ -489,8 +487,7 @@
> if (!pr->pblk)
> return_VALUE(-ENODEV);
>
> - for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
> - memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
> + memset(pr->power.states, 0, ACPI_PROCESSOR_MAX_POWER * sizeof(struct acpi_processor_cx));
>
> /* if info is obtained from pblk/fadt, type equals state */
> pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
> @@ -536,8 +533,8 @@
> return_VALUE(-ENODEV);
>
> pr->power.count = 0;
> - for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
> - memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
> +
> + memset(pr->power.states, 0, ACPI_PROCESSOR_MAX_POWER * sizeof(struct acpi_processor_cx));
>
> status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
> if (ACPI_FAILURE(status)) {
> @@ -609,6 +606,27 @@
>
> cx.type = obj->integer.value;
>
> + //Test if the first entry is a C1 state, if not we fake one
> + if ((cx.type != ACPI_STATE_C1) && i == 1) {
> + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Faking C1 State"));
> + struct acpi_processor_cx c1_fake;
> + memset(&c1_fake, 0, sizeof(c1_fake));
> +
> + c1_fake.address = 0;
> + c1_fake.type = ACPI_STATE_C1;
> + c1_fake.latency = 0; //How long needs a HLT instruction to execute ?
> + c1_fake.power = 0; //We don't know anything about the power consumption so we set it to 0
> + //We copy our fake C1 state over to the power states
> + (pr->power.count)++;
> + memcpy(&(pr->power.states[pr->power.count]), &c1_fake, sizeof(c1_fake));
> + //Finally we avoid to have more power states than ACPI_PROCESSOR_MAX_POWER
> + if(count == ACPI_PROCESSOR_MAX_POWER)
> + count--;
> +
> + //c1_fake should be freed automaticaly
> + }
> +
> +
> if ((cx.type != ACPI_STATE_C1) &&
> (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
> continue;

--
Bruno Ducrot

-- Which is worse: ignorance or apathy?
-- Don't know. Don't care.

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