RE: acpi_enable_wakeup_device question

RE: acpi_enable_wakeup_device question

[Li, Shaohua]

Hi,
Please look at the P212 in 2.0a or P215 in 2.0c(_PRW method). The reason
is ACPI recommend disabling interrupt, please look at the example at the
end of the section. Yes, enabling interrupt possibly doesn't matter (my
test shows it works), but we don't know if it works for all systems, so
we just obey to spec.

Thanks,
Shaohua

>-----Original Message-----
>From: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org [mailto:acpi-devel-
>admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org] On Behalf Of Dmitry Torokhov
>Sent: Monday, August 23, 2004 2:19 PM
>To: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
>Subject: [ACPI] acpi_enable_wakeup_device question
>
>Hi,
>
>I see the following comment in drivers/acpi/sleeip/wakeup.c:
>
>/**
> * acpi_enable_wakeup_device - enable wakeup devices
> *      @sleep_state:   ACPI state
> * Enable all wakup devices's GPE
> */
>void
>acpi_enable_wakeup_device(
>        u8              sleep_state)
>{
>        struct list_head * node, * next;
>
>
>        /*
>         * Caution: this routine must be invoked when interrupt is
disabled
>         * Refer ACPI2.0: P212
>         */
>
>But I can not seem to find anything related to that on p.212 ACPI 2.0c.
>As far as I can tell functions called by acpi_enable_wakeup_device
(such
>as acpi_set_gpe_type and acpi_enable_gpe) can be safely called from
>process context. Why this function has to be called with interrupts
>disabled?
>
>Thanks!
>
>--
>Dmitry
>
>
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Re: acpi_enable_wakeup_device question

[Dmitry Torokhov]

On Monday 23 August 2004 01:29 am, Li, Shaohua wrote:
> Hi,
> Please look at the P212 in 2.0a or P215 in 2.0c(_PRW method). The reason
> is ACPI recommend disabling interrupt, please look at the example at the
> end of the section. Yes, enabling interrupt possibly doesn't matter (my
> test shows it works), but we don't know if it works for all systems, so
> we just obey to spec.
> 

Thank you for pointing the exact place in the spec, although I do not
agree with your reading of it. I think it says that before entering the
sleep state all 3 conditions should be satisfied, but it does not
necessarily specifies the order in which the actions should be performed.
For example checking the validity of requested sleep state in no way
relies on interupts being disabled as _PRW is required to return the same
information every time it is invoked and as far as I can see Linux ACPI
implementation only executes it at device scan.

I think that it is safe to move acpi_enable_wakeup_device up a bit;
having interrupts disabled when entering sleep state is completely
reasonable though.

-- 
Dmitry


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acpi_enable_wakeup_device question

[Dmitry Torokhov]

Hi,

I see the following comment in drivers/acpi/sleeip/wakeup.c:

/**
 * acpi_enable_wakeup_device - enable wakeup devices
 *      @sleep_state:   ACPI state
 * Enable all wakup devices's GPE
 */
void
acpi_enable_wakeup_device(
        u8              sleep_state)
{
        struct list_head * node, * next;


        /*
         * Caution: this routine must be invoked when interrupt is disabled
         * Refer ACPI2.0: P212
         */

But I can not seem to find anything related to that on p.212 ACPI 2.0c.
As far as I can tell functions called by acpi_enable_wakeup_device (such
as acpi_set_gpe_type and acpi_enable_gpe) can be safely called from
process context. Why this function has to be called with interrupts
disabled?

Thanks!

-- 
Dmitry


-------------------------------------------------------
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100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33
Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift.
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