The name of the operation region, SMIP, suggests that the BIOS has an

SMI trap on that port. In that case, writing to that port will result in

the BIOS taking control. We have little idea what it could be doing.

Could be it's trying to access the OHCI controller which has been

suspended already.
This sounds kind of like the Toshiba laptops that go nuts somewhere if

the AHCI SATA controller gets put into suspend state before the system

suspends..
The ACPI spec has the following to say about the _PTS method:
"The platform must not make any assumptions about the state of the

machine when _PTS is called. For example, operation region accesses that

require devices to be configured and enabled may not succeed, as these

devices may be in a non-decoding state due to plug and play or power

management operations."
Yeah, and this is a PCI Express system not AGP, so it wouldn't load anyway.
--

Robert Hancock      Saskatoon, SK, Canada

To email, remove "nospam" from hancockr@nospamshaw.ca

Home Page: http://www.roberthancock.com/
--

That is from the 3.0 spec though. And it looks like the definition changed

from pre-3.0 to 3.0 and above.
This is what the 1.0B spec says (and this is also repeated verbatim in 2.0,

2.0a, 2.0b, and 2.0c):
"The _PTS control method is executed by the operating system at the beginning

of the sleep process for S1, S2, S3, S4, and for orderly S5 shutdown. The

sleeping state value (1, 2, 3, 4, or 5) is passed to the _PTS control method.

Before the OS notifies native device drivers and prepares the system software

for a system sleeping state, it executes this ACPI control method. Thus, this

control method can be executed a relatively long time before actually

entering the desired sleeping state. In addition, the OS can abort the

sleeping operation without notification to the ACPI driver, in which case

another _PTS would occur some time before the next attempt by the OS to enter

a sleeping state. The _PTS control method cannot modify the current

configuration or power state of any device in the system. For example, _PTS

would simply store the sleep type in the embedded controller in sequencing

the system into a sleep state when the SLP_EN bit is set."
According to the earlier versions of the ACPI spec, Linux is doing the wrong

thing - we should call _PTS() before we start powerding down devices, or

notifying device drivers to start suspending.
So, my limited understanding of what we currently do for ACPI suspend-to-RAM

is:
1) Freeze processes/ devices

2) Put all devices into low power mode

3) Execute _PTS()

4) Suspend system
So the problem is - our current suspend order is fine for ACPI 3.0 and above,

but for pre-3.0 systems, this violates the older specs, where 2) and 3) 
No, it looks like the BIOS is obeying the older specs, and Linux is at fault

here for breaking the suspend logic of pre ACPI 3.0 systems.
-Carlos

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E-Mail: carlos@strangeworlds.co.uk

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--

Well, citing from the ACPI 2.0 specification, section 9.1.6 Transitioning from

the Working to the Sleeping State (which is what we're discussing here):
3. OSPM places all device drivers into their respective Dx state. If the device

   is enabled for wake, it enters the Dx state associated with the wake

   capability. If the device is not enabled to wake the system, it enters the

   D3 state.

4. OSPM executes the _PTS control method, passing an argument that indicates

   the desired sleeping state (1, 2, 3, or 4 representing S1, S2, S3, and S4).
You're wrong, sorry.
Greetings,

Rafael

--

This is that same section from ACPI 1.0B:
3. The OS executes the Prepare To Sleep (_PTS) control method, passing an

argument that indicates the desired sleeping state (1, 2, 3, or 4 representing

S1, S2, S3, and S4).
4. The OS places all device drivers into their respective Dx state. If the

device is enabled for wakeup, it enters the Dx state associated with the

wakeup capability. If the device is not enabled to wakeup the system, it

enters the D3 state.
No, I'm not entirely wrong - read the 1.0 spec, and read section 7.3.2 of the

ACPI 2.0 spec.
* ACPI 1.0 is very clear - we are breaking the 1.0 spec
* ACPI 2.0 is contradictory - section 7.3.2 repeats 1.0 ad verbatim (which is

what I quote in reply to Robert Hancock), but as you point out, 9.3.2 says

the opposite.
So, 1.0 and 3.0 are very clear and rather different on this, and 2.0 is

contradictory (and I presume this is one of the points ACPI 3.0 set out to

clean up).
I will rescind my point on ACPI 2.0 - I don't know what we should or shouldn't

be doing there, the spec is unclear.
But for ACPI 1.0, we are doing the wrong thing.
-Carlos

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E-Mail: carlos@strangeworlds.co.uk

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--

Correct me if I'm wrong, but it appears ACPI 1.0 wants _PTS called

before any devices are suspended, ACPI 2.0 is contradictory, and ACPI

3.0 says that you can't assume anything about device state. My guess is

that unless Windows has different behavior depending on ACPI version, it

probably has called _PTS before suspending devices all along. Therefore

it would likely be safest to emulate that behavior, no?
--

Robert Hancock      Saskatoon, SK, Canada

To email, remove "nospam" from hancockr@nospamshaw.ca

Home Page: http://www.roberthancock.com/
--

Well, I don't think so.
In fact ACPI 3.0 repeats the 2.0 wording in section 9.1.6 (so the current

requirement seems to be to put devices into low power states before calling

_PTS) and I _guess_ there was a change in the default behavior of Windows that

caused the specification to be modified (I'd bet that was between 2000 and XP

or something like this).
IMO, we should check which version of the specification we're supposed to

follow, on the basis of FADT contents, for example, and follow this one.
Thanks,

Rafael

--

You seem to put a lot of trust in a piece of documentation.
Do you realize how those pieces of paper are written? They are written by

people who have absolutely *nothing* to do with the actual implementation,

and whose job it is to write documentation. And while the people who

actually do the programming etc are supposed to help them, the two parties

generally detest each other.
Technical writers hate the "real engineers" for not helping them, and the

"real engineers" tend to dislike having to be pestered to explain their

stuff and have to read through some document that isn't meant for them,

but that they need to sign off on.
In other words: please do *not* expect that the documentation actually

matches reality. You seem to think that the documentation came first 
No, we should try to figure out what Windows does. *If* windows checks the

version, we should do that too. But we should absolutely *not* just assume

that the documentation is an accurate picture of reality.
Does anybody know how we could find out? 
			Linus

--

Run it in a virtual machine, with the ACPI methods of interest wired to

output to some port, and log that I/O port in the monitor/emulator.
--

Do not meddle in the internals of kernels, for they are subtle and quick to panic.
--

Well, it seems that if one had a checked (debug) build of Windows (or at

least the acpi.sys driver) installed, as well as a copy of the Microsoft

ASL compiler, they could compile and temporarily override the DSDT with

a hacked one that would output what the device power states were in some

fashion (maybe through the kernel debugger). Some info about this here:
http://download.microsoft.com/download/1/8/f/18f8cee2-0b64-41f2-893d-a6f...
I suspect that might require more Windows hacking skill and/or

motivation than one might be likely to find on this list, though :-)
--

Robert Hancock      Saskatoon, SK, Canada

To email, remove "nospam" from hancockr@nospamshaw.ca

Home Page: http://www.roberthancock.com/
--

I think we should follow section 9.3.2 that is explicit and has been reiterated
Yes, we are.
OK, I think we can rearrange things to call _PTS early for ACPI 1.0x-compliant

systems.
Thanks,

Rafael

--

Adding Linux-ACPI to CC.
The following is a hack to illustrate what I'm getting at (this is

tested on x86-64) (it's a hack since it does all the ACPI prepare bits

during set_target() for the pre ACPI 3.0 systems, rather than prepare() -

whether this can be cleaned up to move out just the _PTS() call, I don't

know).
It abuses suspend_ops->set_target(), but was the easiest way to quickly

demonstrate this (since the kerneldoc for set_target() says it will always

be executed before we suspend the devices).
-Carlos

---
 drivers/acpi/sleep/main.c |   26 ++++++++++++++++++++++----

 1 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c

index 96d23b3..89e708b 100644

--- a/drivers/acpi/sleep/main.c

+++ b/drivers/acpi/sleep/main.c

@@ -77,8 +77,19 @@ static int acpi_pm_set_target(suspend_state_t pm_state)

 	} else {

 		printk(KERN_ERR "ACPI does not support this state: %d\n",

 			pm_state);

-		error = -ENOSYS;

+		return -ENOSYS;

 	}

+

+	/*

+	 * For ACPI 1.0 and 2.0 systems, we must run the preparation methods

+	 * before we put the devices into low power mode.

+	 */

+	if (acpi_gbl_FADT.header.revision < 3) {

+		error = acpi_sleep_prepare(acpi_target_sleep_state);

+		if (error)

+			acpi_target_sleep_state = ACPI_STATE_S0;

+	}

+

 	return error;

 }
@@ -91,10 +102,17 @@ static int acpi_pm_set_target(suspend_state_t pm_state)
 static int acpi_pm_prepare(void)

 {

-	int error = acpi_sleep_prepare(acpi_target_sleep_state);

+	int error = 0;
-	if (error)

-		acpi_target_sleep_state = ACPI_STATE_S0;

+	/*

+	 * For ACPI 3.0 or newer systems, we must run the preparation methods

+	 * after we put the devices into low power mode.

+	 */

+	if (acpi_gbl_FADT.header.revision >= 3) {

+		error = acpi_sleep_prepare(acpi_target_sleep_state);

+		if (error)

+			acpi_target_sleep_state = ACPI_STATE_S0;

+	}
 	return error;

 }

--

Please, don't do that.
The current code is following the ACPI 2.0 specification (and later) quite

closely and while we can add a special case for the 1.0-copmpilant systems,
acpi_gbl_FADT.header.revision is equal to 3 for ACPI 2.0-compilant systems
Thanks,

Rafael

--

OK, sorry, the approach is generally reasonable, IMO, but it needs to be a bit

more fine grained.
I'll try to prepare some patches along these lines soon.
Thanks,

Rafael

--

I know, hence this was marked as a hack and not signed off; it's just a 
Much appreciated - I'm much happier with someone who's more familiar with this

code than I working on it.
-Carlos
(Now going back to unwrapping Christmas presents...)

--

E-Mail: carlos@strangeworlds.co.uk

Web: strangeworlds.co.uk

GPG Key ID: 0x23EE722D

--