How does ACPI work--Really.

[jsteph]

Ok, I've been having a difficult time getting a knowledgable answer on this:

When one has a motherboard that supports ACPI, and an OS, (win98se in this case) that *claims* to support ACPI, how does one set it up, and does it ever work?

For example, the crux of my question is this: If I have settings for monitor-off, hd-off, and susspend time in the BIOS setup, then what on earth are the Control Panel settings there for in the OS? And truthfully--which one takes precedent? It's been my experience that there is no clear definintion of this, and in practice, neither seems to really work. Sometimes if I enable acpi in the bios, then occasionally it will shut the hd & monitor down within the same day (that is, I set it for 15 minutes, but 6 hours later it turns off--so I guess we'll call that close (!!!???). And then if I *disable* it in bios, and use the OS control panel settings, it works as far as timing on turning off the monitor/hd, but the suspend neverworks??!! Or, it suspends, but somehow locks up in suspend mode and does NOT come out, regardless of how much I click, hit keys, attempt remote connections, etc, etc.

What's the real story here? Is this just a big train wreck where MS blames the hardware people and the hardware people blame MS? Thanks for any insight...
--jsteph

 

[ski]

I'm afraid that if you ask 1000 different people about their experiences with ACPI, you will get 1000 different answers.

Case in point:
My O/S's(Win 98) manual standby and its 3 timed settings in 'Power Mgt. Properties' worked flawlessly until I upgraded my hardware(MB, CPU, RAM, video and sound cards, and PS).
Now the O/S's timed monitor and HD settings work well, its timed system standby does not work at all, and its manual standby works ok most of the time(fails to wake up approx. once out of every 50 times). Which is fine with me since I use only manual standby.
But manual standby failed to work at all after I updated the video card's drivers with about 6 different versions, and I was forced to revert back to the original ones.

Never messed too much with the BIOS ACPI, since it seemed to be overpowered by the O/S.

 

[TekTippy4U]

My definitive answer to the last part of your question is an overwhelming "probably".....considering all the devices and settings that need to be "managed" just to have power'management'.....If ACPI is working as expected and for quite a while after changing "anything", then you are a fortunate person indeed....

If you throw in the "Wake on Modem Ring" under LAN settings in the BIOS, if present, then you really start to have fun...

Wish I could've been more helpful, just had to share my
120 volts worth......

TT4U

Notification:
These are just "my" thoughts....and should be carefully measured against other opinions....I try very hard to impart correct info at all times.

 

[jsteph]

Thanks for the replies & insights. Just what I was afraid of--a train wreck. I guess it's time to go back to flying toasters when I'm away from the pc.
--jsteph

 

[bcastner]

The hardware manufacturer's do not know if you are going to be using an ACPI aware OS or not. And if so, which one. The best advice is to enable ACPI support in the BIOS but do not set any timer settings or system state settings in the BIOS.

Let the ACPI-aware OS try to manage things. If you enable ACPI timer settings in the BIOS and in the OS you are almost assured that it will not work satisfactorily.

The BIOS needs to provide a compliant set of services to the aware OS. There are standards for these services, and their specific implementation for Microsoft OS products are clearly enumerated by Microsoft.

If your motherboard and BIOS have passed certification, there will almost certainly be a sticker on the box from the processor manufacturer as well as from Microsoft specifying that certification has been passed. If you purchase a machine without certification from the processor manufacturer and from Microsoft that the computer is WHQL certified, it is uncertain what your actual results may be.

There is no "train wreck" if you buy certified products. That is exactly what the certification process is designed to prevent.

For later versions of the Microsoft OS product line the certification process extends even further to add-in Third Party hardware. In these cases the software drivers and the compliance with the interface standards used can be tested and certified.

If you buy and use un-certified hardware and software drivers, the results are uncertain.

 

[pmonett]

Very sorry to disagree, but "certified" products are, in no way, a guarantee of proper ACPI function.
I have long since abandoned suspend modes of any kind. In my experience, the functionality practically ALWAYS works fine in the first three weeks, then degrades steadily at a more or less random pace.
As far as hardware is concerned, I have tried using only MS-Windows certified hardware, but that has not changed anything.
Suspend is a most definite train wreck. Since I know need 24/7 functionality out of my PCs, it doesn't really bother me though.
The only energy-saving I still insist on using is screen suspend. Since XP, I have had almost no issues on that (save on one PC where the settings are for a 1-minute cutoff, and once a week the screen turns back on 1 second later until I manually reset the parameters).

Just my experience.

Pascal.

 

[jsteph]

bcastner,
Thanks for the information. Now, that's fine--for Windows. What about all the flavors of Linux, or whatever other os the motherboard may be running? I'm asking only semi-rhetorically, I'm curious to know if MS is the only one who certifies for this, of if it's a consortium, etc, and if the standards are different for different OS's.

It would seem to me that ACPI shouldn't be 'owned' by MS, that it should be an open standard set by an outside group that MS must adhere to--not the other way around. This way, if MS makes a single statement--"Windows xxx Supports ACPI", and a mother board makes the statment "This Motherboard supports ACPI", then that's it--it's guaranteed to work--period. Not "MS might support ACPI, but only for this motherboard/bios/chipset combination, not that one, etc, but not if you run active directory, or maybe some other combination of options within our os--we can'b be sure, but it might run if you don't touch anything...", etc. etc.

Sorry for the rant but it'd be nice to think that just once the hardware and software people could agree on something and have it just work, period.
--jsteph

 

[bcastner]

pmonett,

"I have long since abandoned suspend modes of any kind. In my experience, the functionality practically ALWAYS works fine in the first three weeks, then degrades steadily at a more or less random pace."

The only truely random element at work would be if something was happening to the hibersys.fil on the hard drive. This is a reparable issue. Everything else in your statement suggests the non-random behavior of user introduced software and/or system settings. There is a limit to what the OS and hardware people can control.

 

[bcastner]

jsteph,

ACPI is a standard that is not under one manufacturer of hardware or software's control. There are non-Windows ACPI compliant OS implementations. Intel for one keeps a list of OS implementations that are capable of being in compliance with their processor families, and details can be found on their site.

If the OS does not natively support ACPI, most BIOS offer some settings that can be used to provide ACPI features. What causes problems is trying to have two masters over the process, the BIOS and the OS, at the same time. If the OS supports ACPI, let it do the job alone, or configure the OS at installation to use an Advanced Power model without ACPI. For example:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;299340

 

[pmonett]

bcastner:

Interesting information. The only user-introduced software running on my Internet PC (aside from a minimal XP Pro install) is the connection software and Tiny Personal Firewall.
As for the settings, there are so many in XP that it is certainly difficult to be sure that each and every one of them is compliant with ACPI wishes.
As far as ACPI settings are concerned, what I know about them is right-clicking on the desktop and going to Screen Saver - Power and using the options there.

I will have to check this hibersys.fil file - don't believe I have one, but MS is always full of surprises.

Pascal.