Talk:Advanced Configuration and Power Interface

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Interface not Feature[edit]

"The other important feature of ACPI is in bringing power management features currently only available in portable computers to desktop computers and servers." This sentence is some kind of missleading. As the name says ACPI is an "interface" not a feature list. Of course ACPI defines system states and many things more but it is not mandatory that they exist. But if they have do be as defined in the specification.

--mac_c 10:30, 13 Aug 2004 (UTC)


The currently exiting APM model ...: sounds like APM is what is sold with today's computers, while ACPI is still under development. Is this correct ?? -- Frau Holle 20:54, 7 Sep 2004 (UTC)

I suggest the following "This stands in contrast to the ACPI predecessor, APM, which assigns power management control to the BIOS..." Bpeckham (talk) 08:10, 3 July 2008 (UTC)

ACPI still under development?: It depends on who you ask. Generally ACPI is a bunch of concepts and not a real piece of hardware. And the development of these concepts was finished some time ago. But the problem is that some hardware venodors still use old implementations of ACPI (i.e. ACPI v1.2 instead of ACPI 2.0). That makes it a little bit hard to write good driver modules for that particular hardware. Another problem is that until ACPI 2.0 the communication channels between ACPI an the OS were not specified exactly enough so the developers were allowed to use what they prefer. And that lead to several problems which are still present. --mac_c 13:05, 14 Oct 2004 (UTC)

assigns .. control to the BIOS: sounds as if a BIOS is a process running simultaneously with an OS kernel. In my understanding, a BIOS can provide routines that can be called by the OS, but it is not precise language saying that the BIOS is in control of anything. I would like to see an expert comment on this or improve the article. Thanks, Frau Holle 20:54, 7 Sep 2004 (UTC)

The BIOS controls everything! —The preceding unsigned comment was added by Quantum Burrito (talkcontribs) 00:01, 15 January 2007 (UTC).


It has been suggested that the ACPI article be merged into this one. I agree. Discuss. - dcljr (talk) 01:24, 26 September 2005 (UTC)

apparently this has happened. --MarSch 16:43, 7 May 2006 (UTC)

Linux still has incomplete support for ACPI.[edit]

Linux still has incomplete support for ACPI.

I disagree. Linux supports almost all ACPI hardware, and supports all sleep states. Hibernation is now fully supported. Does anyone disagree with removing this? 01:41, 29 May 2006 (UTC)

I cannot find anything about it in the refs, so go ahead. --MarSch 11:03, 29 May 2006 (UTC)
Linux fails to work properly with buggy BIOSes and DSDTs - yet windows still copes. Also, to the last of my recollection, speedstep isn't handled via ACPI but (still) directly frobbing the PSRs. --moof 12:02, 29 May 2006 (UTC)

It is not fair to blame the "buggyness" of Linux or even windows on any unspecified piece of hardware. Essentially, it is up to the final OEM/ hardware manufacturer to "debug" ACPI and get it working with each OS they want to support. Many times there will need to be a work around which is then tested on a specific version of a specific OS. It is unlikely a desktop system will be tested with more than one OS in the contemporary market(whatever OS is pre-installed).
Because Linux is not as commonly installed as Windows and because there are so very many Linux Distro's, it is almost never likely that ACPI support will be as robust for the Linux crowd as a general rule. This is not the fault or a deficiency in any Linux distribution, it is the legacy from trying to have infinite hardware configuration compatible with infinite software packages.--Riluve 20:14, 12 June 2006 (UTC)
I got a computer to suspend-to-RAM (S3) with Ubuntu but it took a long time to resume from the S3 state (about as long as booting Windows on the same machine). Secondly, before it would go into S3, it would turn the hard drive off, back on, then off again (that would seem to add some extra wear to the drive). I want to buy a desktop but I can't even find a report of one that can suspend-to-RAM with Linux or BSD. The reports I have found have all been for laptops. Jobbon 00:03, 5 March 2007 (UTC)

I think there might be simple explanation for ACPI not working correctly on Linux. Message from Bill Gates - source 11:23, 14 April 2007 (UTC)

Is there a source for them actually doing this rather than just talking about it? This really shouldn't be linked in the article if there's no solid proof that this even happened. Macthorpe 10:19, 23 April 2007 (UTC)

an internal primary sourced note

"(This is not censorship. That's an internal primary sourced note, we can't verify, which makes implications we can't source and which is unrelated the the actual ACPI standard as it exists)", Jimmi Hugh

Please quote from the Wikipedia policy regarding verifiability, that states that an 'internal primary sourced note', is not suitable. Especially as this is a duly entered document in a court case. —Preceding unsigned comment added by Emacsuser (talkcontribs) 22:04, 20 January 2009 (UTC)

Linux's ACPI implementation is no less complete than that of FreeBSD (in some places it is arguably more complete) and certainly more so than OpenBSD's current (2008) implementation. I cannot see anything on the Linux ACPI page suggesting that there are parts yet to implemented (however it is true that frameworks to do things like adjust HOW the system cools itself using OS controlled fans are only just emerging). An inability to suspend and resume need not be related to an incomplete ACPI implementation. Further Linux has been able to use ACPI for CPU scaling for a few years (in addition to other methods). (talk) 07:47, 17 March 2008 (UTC)

ACPI States:[edit]

Do systems really distinguish between S4 and G2? To the best of my knowlege the system does not know or care of the difference. In the case of windows, AFAICT, S4 the boot process simply looks for the hibernation file, and if one is found, then the it is used to restore the system. So the hardware has no reason to distinguish.

AFAICT the difference between G2 and G3 in most system is that in G2 the PSU still provides power to certain components (system clock, network card, etc), while in G3 the PSU provides no power to the system, either due to power outage, or removed plug.

Is the above all correct, or am I missing something? Tacvek 20:57, 30 May 2006 (UTC)

Not correct.
G2=S5 - there is no preparation for recovery or any recovery after G2/S5. There is not a giant distinction from the hardware point of view, but their is one - the S4 sleep state register will not be set in G2/S5. Only if this register is set will anyone (the BIOS or the OS) try to do a recovery (including looking for a hibernation file). The BIOS specifically will behave very differently between G2/S5 and G1/S4. e.g. after a G2/S5 the BIOS will HAVE to perform a full POST. After a G1/S4, it may choose to do an abbreviated POST. After a G2/S5, the BIOS will boot with INT19 which may load GUB or LILO. After a G1/S4, a properly working BIOS will NOT do an INT19, it will NOT load the MBR, rather it will jump to a pre-specified location/entry point for the OS that performed the G1/S4 in the first place. Additionally, the discussion of G2/G3 is a little confused. G2/G3 are indistinguishable from the machine point of view. No additional system state or power is maintained in G2 vs G3. They are merely technically different in that with G3 the power is physically removed and the software controlled powerbutton has no chance then to re-apply power to the system. --Riluve 20:37, 12 June 2006 (UTC)
Sounds like it would have made sense to put the "S4 sleep state register" on the system partition but they put it in the CMOS so the computer could come out of hybernation more quickly. That would mean it is safe to unplug the computer when it is hibernated, so long as the battery isn't removed (and has enough charge), in that it will still restore the hybernated state. You could hibernate the computer, unplug the computer to remove an expansion card, and the hybernated state would still be restored. Is that correct? Jobbon 04:45, 5 March 2007 (UTC)

Not working perfectly[edit]

ACPI does not work flawlessly as one might think. Windows XP for example has problems sometimes with coming back from one of the S states. This should be mentioned in my opinion. --Abdull 11:19, 5 June 2006 (UTC)

ACPI requires a high level of co-operation between the device drivers, the hardware, and the OS itself. One of the biggest problems with device driver development for Windows over the past several years has been the issue of getting the sleep-state/power management code right. The Windows Driver Foundation is a programming model recently introduced by Microsoft to address a lot of these problems when developing drivers for Windows. Warrens 13:35, 5 June 2006 (UTC)
The incomplete or "flawless" aspect of ACPI is really up to the final vendor/(OEM). If ACPI is not working properly complain to the people you bought it from. Unfortunately, these companies set aggressive schedules which don’t allow them to fix all the bugs in their hardware. They just do the best they can and then shove their machines onto the market because they know they can pass their issues off on other associated venders like Windows or the BIOS.
And no, I am no Windows apologist, I do however work with hardware manufacturers and I watch them make these business decisions everyday.--Riluve 20:07, 12 June 2006 (UTC)

G2 Soft Off - Possible disassembly issue[edit]

The section recommends unplugging the desktop, whereas I have read that it is advisable to leave the desktop plugged in, but the power supply off to ensure that it is properly grounded. I don't feel qualified to change the article myself, but I do feel that it might deserve another look. Tyler 06:24, 12 August 2007 (UTC)

Windows-Vista, ACPI, Fans, and Heat[edit]

I've been seeing quite a few blogs about heat problems under Windows-Vista. Last week I purchased a system with Windows-Vista preinstalled and noticed that the Pentium-D in it runs about 10C degrees hotter than a similar system which also has a Pentium-D but runs Windows-XP. After installing "PC Wizard 2008" I noticed that the processor fan speed on the Vista machine was only 1000 RPM whilst the processor fan speed on the XP machine was 2200 RPM. After much investigation which included BIOS updates, I am now convinced that this is not a hardware problem but may be caused by VISTA overriding the BIOS ACPI fan + temperature tables. The following page documents my technical observations:

Why would they slow down the fans? Perhaps to extend battery life but this only makes sense on laptops but not PCs or workstations. To fix this, customers require access to the ACPI stuff via the "power profile" panel.

This whole thing reminds me of something that happened back in 1995. Many BIOS routines were 16-bit and windows was wasting a lot of time thunking between 32-bit and 16-bit so the good folks at Microsoft just wrote a bunch of 32-bit BIOS drivers to replace the 16-bit ones discovered at boot. It took some time to get it debugged but it was worth the effort. I think this ACPI/OSPM stuff will eventually work too. --Neilrieck (talk) 13:28, 16 December 2007 (UTC)

"Microsoft just wrote a bunch of 32-bit BIOS drivers." - I've never heard of this before, unless you're talking about the kernel introduced in windows 95? (talk) 05:54, 19 December 2007 (UTC) is gone?[edit] is gone?

Minusf (talk) 17:18, 12 April 2008 (UTC)

yes, I also have this issue.. —Preceding unsigned comment added by (talk) 06:03, 7 June 2010 (UTC)

Criticism section edited[edit]

I removed the Bill Gates paragraph. After going through the linked articles and the PDF copy of that email, it seems to me that it's irrelevant and quite impossible to level any sort of charge against Microsoft over that. There are implementations of ACPI for both Linux [1] and the BSDs [2], and like the Windows one, they all vary in effectiveness depending (mostly) on the hardware manufacturer. I'm not sure what OS X uses.

APM is also a Microsoft-created (in concert with other HW manufacturers) open standard, which has essentially the same problems as ACPI.

Unless someone can come up with an email from that doc repository or some sort of other evidence that Microsoft somehow deliberately crippled ACPI to prevent it from working in other operating systems, the paragraph is superfluous at best. That email reads to me more like the musings of a man whose company just spent a lot of money with partners to develop something, only to see it adopted by its main competitor for free. It's an interesting general comment on how Gates thinks perhaps, and even on Microsoft culture, but it proves nothing and is irrelevant to ACPI. Thoughts? §FreeRangeFrog (talk) 20:16, 9 October 2008 (UTC)

Criticism on the Criticism section[edit]

It says "Where hardware does not conform to ACPI, but claims to do so, the software interoperating with that hardware is faced with a dilemma" and so on, but is this really a criticism against ACPI? Won't we face the same problem everywhere there's a standard? If I write a buggy Quicksort implementation, is it the Quicksort algorithm that is the problem or is it my implementation of it? Why not just say something along the line of that it's tricky to implement correctly? Hamag (talk) 12:28, 14 October 2008 (UTC)

  • No, it's not valid criticism at all. Be bold and edit it! §FreeRangeFrog 21:30, 14 October 2008 (UTC)
    • Heh, I came to Wikipedia to learn a little about ACPI so I know next to nothing about it. For that reason I'm not bold enough to edit the page but instead hoped that someone a bit more knowledgeable than me in the field would. I know it may sound like a cop-out but the best I can do is remove the specific criticism altogether, but at the same time I think there might be some merit to it as how ACPI may be difficult to implement correctly and this causes hardware manufacturers to create not fully ACPI-compliant devices while still claiming compliance. Hamag (talk) 09:17, 17 October 2008 (UTC)
      • As usual, the standard disclaimer about phrases that contain both "learn" and "Wikipedia" apply. There's lots of information out there, Google is your friend. I'd love to make this article useful, but I gave up on actually improving articles here a long time ago, because you can spend a week working on something just to have a bored admin with a grudge revert all your changes and force you to slog through bureaucratic bullshit that only they can win. So I just trim a bit here and add a bit there :) §FreeRangeFrog 17:12, 17 October 2008 (UTC)

an internal primary sourced note[edit]

"(This is not censorship. That's an internal primary sourced note, we can't verify, which makes implications we can't source and which is unrelated the the actual ACPI standard as it exists)", Jimmi Hugh

Please quote from the Wikipedia policy regarding verifiability, that states that an 'internal primary sourced note', is not suitable. Especially as this is a duly entered document in a court case. —Preceding unsigned comment added by Emacsuser (talkcontribs) 22:04, 20 January 2009 (UTC)

Well firstly...

"All quotations and any material challenged or likely to be challenged must be attributed to a reliable, published source using an inline citation"

Which of course makes the claim that the material must be published and reliable, not something linked directly from some guys anti-microsoft website.

"Articles should rely on reliable, third-party published sources with a reputation for fact-checking and accuracy"

You posted a primary source, which requires biased interpretation to take away any facts from. It also skips the level in which verification by the third party is done, whether the source is correct or not.
This can all be found at WP:SOURCE which deals with sources, as you asked. However, this is an external link, so more importantly...

"Is the site content proper in the context of the article (useful, tasteful, informative, factual, etc.)?"

... from WP:LINKS, which seems to contradict this biased, unhelpful link, which can't be considered factual because it has no context, only pure data.

"Links to blogs and personal web pages (including fansites), except those written by a recognized authority (this exception is meant to be very limited; as a minimum standard, recognized authorities always meet Wikipedia's notability criteria for biographies)."

Which speaks for itself.

"Sites which fail to meet criteria for reliable sources yet still contain information about the subject of the article from knowledgeable sources."

This will gain the link some support, if the other issues are supressed, if the link isn't on a generic, non-notable anti-microsoft webiste. Forgive me finding so few, I oly had a quick look for actual quotes. - Jimmi Hugh (talk) 22:34, 20 January 2009 (UTC)
Whether it is notable or not, it's still off context for the ACPI article, considering there is no ulterior proof of tampering by Microsoft anywhere in those court documents that I could find. This 'Emacsuser' account seems to be used to add mostly negative content to Microsoft articles... what a coincidence. §FreeRangeFrog 04:11, 21 January 2009 (UTC)
I agree. But a few direct quotes from policy that shoot it down can't hurt either. - Jimmi Hugh (talk) 04:25, 21 January 2009 (UTC)
This User:Emacsuser person actually emailed me to argue about the Microsoft Windows article the other day, claiming that the idea that Windows wasn't originally designed for Internet security was factually wrong. He really was quite rude about it, and he actually refused to address any of the points I made. Warren -talk- 15:39, 21 January 2009 (UTC)

Hey guys, stick to the 'fact's, why don't you ::

This isn't the place, but you chose to bring it up; if it's all right with you, I'll post the full text elsewhere .. emacsuser (talk) 16:45, 22 January 2009 (UTC)
Hey, afraid I don't know what a homium is, with my limited knowledge of latin. Assuming it's a negative argumentative technique, like an Ad hominem, for example, then I hate to say it, but all those comments were valid, the only criticism of you personally was fairly reasoned, and it's important to at least consider the possibility you have some bias, whether that makes your edits entirely invalid or not. Sorry if you felt you were being attacked here, I'm sure it wasn't the editors intentions, and they'd be happy to discuss any Wikipedia article with you on the relevant page. If you have any sources to back up claims about the design of Windows, or on Microsofts design of ACPI, then feel free to add them. - Jimmi Hugh (talk) 19:21, 22 January 2009 (UTC)
What business do you or 'warren' have in personally criticizing anyone here. As for discussing on the 'relevant page' I hardly call quoting a private email about another page, *here* as relevant. Also, if you must descend to a condescending dissection of the other fellas grammar then at least get it right.
"An Ad hominem consists of replying to an argument or factual claim by attacking .. the source "

So let me summarize for any late comers, opinions are posted on the MS Windows page with no historical basis. I ask for some citations and *here* my personal integrity gets attacked, by two people, twice and not on the relevant page and one of you invokes a private email as evidence. My chief crime was to post a request for "Citations needed for Security section".
So, come on guys, lets see some 'inline' citations to the relevant sections with the 'citations needed' markers. You're both such clever wordsmiths, it should be a doddle. Now remember, don't email me with masses of verbiage, just insert the citations.
"The response up to now have been a variety of fallacious argumentum absurdum and references to poor grammar" emacsuser (talk) 21:27, 23 January 2009 (UTC)


DSDT redirects to this article, yet there's no mention of DSDT here. Confusing. —Preceding unsigned comment added by (talk) 15:45, 15 May 2009 (UTC)

All ACPI Tables used to be named, but I removed them for as long as there were no adequate descriptions as it was excessively verbose with little content. I will likely add Major ones like the DSDT amongst others again though, so the redirect is appropriate and I will add them as soon as possible. - Jimmi Hugh (talk) 19:24, 1 July 2009 (UTC)
All, also, as you seemed to be asking somewhat, DSDT stands for, "Differentiated System Description Table". - Jimmi Hugh (talk) 19:35, 1 July 2009 (UTC)


I wanted to know when ACPI first appeared. The external links say 1999, the 1.0b specifications release. I like knowing the history because it helps me position the technology. Writers with reliable, even first hand, knowledge might want to add a short background to that date. Ozga (talk) 17:01, 11 September 2009 (UTC)

ACPICA license[edit]

The article says "ACPICA is written in ANSI C and released as free software under the terms of the GNU General Public License." But the souces have a header with an intel license. -- (talk) 16:23, 1 March 2010 (UTC)

Good catch. This however, is a problem with Wikipedia, not this page. There is an assumption (born of Free Software bias mostly) that code has a license. In reality, a specific release of code or binaries is licensed for that release. This concept is approached by the idea of Dual licensing, but has still left us with this incoherent box with a field for a "license" that just doesn't exist. ACPICA is indeed available under the GPL, as well as other licenses, so the statement isn't incorrect, so much as it is meaningless. I'll remove it, and the Infobox in it's entirety. - Jimmi Hugh (talk) 12:09, 2 March 2010 (UTC)

Page Updates[edit]

I am currently reading through the entire 4.0a specification right now and I have been reading a few things in the talk. I will do some modifications to this page in the near future, along with putting some actual assembly code to call the ACPI wake/sleep/shutdown procedures. ~Charles Timko   Talk 〗

I added a Revisions History section. I wasn't sure where exactly it should go in the Section order, but I think it does a nice job covering the major changes in the revisions. ~Charles Timko   Talk 〗


Under what circumstances does the AML bytecode get interpreted and what can it do? Could you give some examples of how it's used? — Preceding unsigned comment added by (talk) 22:30, 28 August 2012 (UTC)

Missing power states[edit]

C1E (Extended Halt) which also reduces CPU voltage C2E (Extended Stop Grant) which also reduces CPU voltage C4 (Deeper Sleep State) C6 (Deep Power Down)

The line feeds were deleted by Wiki, and for some weird reason the Talk page wasn't visible before I logged in but is visible now also after I log out.

Ambiguous antecedent[edit]

Under OSPM responsibilities:

"ACPI requires that once an OSPM-compatible operating system has activated ACPI on a computer, it then takes over ..."

What is "it" - the ACPI, the OS or (grammatically), the computer?

The antecedent of "it" is ambiguous.

ArtKocsis (talk) 15:18, 20 November 2012 (UTC)

First, tell the reader why?[edit]

Excuse my ignorance but it seems to me that an article about ACPI should at least attempt to convey its purpose and usefulness to those who might lack the technical know-how to interpret what purports now to describe it. That is something I cannot do. If you can do it, I suggest that you give it a whirl. QuintBy (talk) 06:10, 14 December 2012 (UTC)


[3] I won't add this to the article because I've not found independent commentary on that email (yet). Someone not using his real name (talk) 14:32, 25 February 2014 (UTC)

Quite interesting, it's a great find! I wouldn't be surprised by even more of such examples. — Dsimic (talk | contribs) 18:40, 25 February 2014 (UTC)

Gates missing[edit]

Bill Gates e-mail is missing in the article how he suggests to use EEE. The German Wikipedia have it in it. (talk) 13:51, 8 August 2014 (UTC)

I see it. Apparently this email came before the court for Comes vs. Microsoft: The article at says, "Microsoft wanted to prevent, as early as 1999, that the ACPI standard for power management of computers can be exploited by open operating systems" (such as Linux). I see no reliable sources in English, except perhaps [4]. Prhartcom (talk) 04:21, 19 August 2014 (UTC)


You are lulling yourself into fantasies, if you start quoting people like "Linus Torvalds" and "Mark Shuttleworth" on this. They have been wrong in many things. Remember 1000hz timer in the kernel. That was Linus. Remember Shuttleworth talking about "ultrasmooth graphics"? That was always possible, but he doesn't know how to configure the kernel for it. To give a hint, it has nothing to do with increasing kernel timer HZ. Rather in my tests 90 hz was optimal for smooth graphics, and low jitter. Imagine all the wasted cpu cycles, with vain calls to interrupts, hardware etc, with a smashing 1000 HZ. Ubuntu kernel from the time I tested, wasn't even low-latency configured, which is the first you turn on, for smooth graphics. Logic goes that you also need to decrease nice level for X, to reduce its bottlenecking. And so forth. But Opensource is for hippies anyway.

There is a lot of vain people in the world, who has gained status, due to that people lack of knowledge of facts. Even Einsteins E=MC2 is really based on pantheism, and might just aswell be a schizophrenic writing GOD=MC2.

Please just try to present the dry facts, without bias, and person-cults. — Preceding unsigned comment added by (talk) 15:03, 4 November 2014 (UTC)

ACPI is now at its 6th rev and UEFI has taken over[edit]

The only thing I could do right now was update the external link to the spec. For all the rest, I hope someone actually knows about the technology and updates the article. — Preceding unsigned comment added by Georgios Tsalikis (talkcontribs) 22:31, 27 April 2015 (UTC)


The latest is 6.1, not 6.0, right?: --Diblidabliduu (talk) 08:56, 30 July 2016 (UTC)