Date: Wed, 29 Aug 2001 19:58:59 -0700 From: Mike Smith <msmith@freebsd.org> To: current@freebsd.org Subject: HEADS UP: ACPI CHANGES AFFECTING MOST -CURRENT USERS Message-ID: <200108300258.f7U2wxq06147@mass.dis.org>
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I have just committed some changes to the way that ACPI works in current. This has an impact on all -current users, so please take a few seconds to read this and feel free to ask questions. The loader now detects ACPI in your system, and loads the ACPI module if it is present. This has major ramifications for the device probe and attach phases of system initialisation. - Root PCI bridges are detected using ACPI. - PCI interrupt routing is now performed using ACPI. - The PnP BIOS is disabled and onboard peripherals are detected using ACPI, and attach to ACPI and not isa. - System-owned resources are detected and reserved by ACPI. - The default system timecounter will be the ACPI timer. There are other changes, these are just the really big ones. I'll try to answer some of the FAQs here, to keep the discussion focussed. Regards, Mike ACPI Integration Mini-FAQ - Who died and left you in charge? - Why are you making such major changes? ACPI is the direction that the Intel/PC architecture is taking. The dominant operating system family on this platform uses ACPI heavily and has done so for the last five years. We have to follow suit or fall badly behind. In addition, ACPI brings us functionality that we have not had in the past. Much discussion on ACPI has been had, and the current direction reflects such consensus as has been reached so far. - Help! ACPI crashes my system. You can disable ACPI by unsetting the 'acpi_load' variable in the loader (for temporary testing) or by setting hint.acpi.0.disable=1 in /boot/device.hints. If you find that you need to do this, please let the FreeBSD ACPI developers (acpi-jp@jp.freebsd.org) know so that we can investigate the problem. - The ACPI module is huge! Do I have to use it? No, you don't. But you may lose functionality if you choose to disable it. The system's legacy probe mechanisms have not been affected by these changes, and we will continue to support legacy platforms for the forseeable future. - Where can I find more information on ACPI? The ACPI homepage is at http://www.teleport.com/~acpi The Intel ACPI Component Architecture homepage is at http://developer.intel.com/technology/iapc/acpi The acpi(4) manpage offers an overview of the debugging options for the Intel ACPI CA code (the core of the ACPI subsystem). An acpi(9) manpage is under development. - Can I compile ACPI into the kernel for debugging? Yes. See NOTES for details on this. Note that you must disable loading of the ACPI module to avoid confusing the kernel linker if you do this. - Is ACPI compatible with APM? No. You must disable APM if you are using ACPI. - Does this change make FreeBSD a "PnP OS"? Not entirely. You may still need to set BIOS "PnP OS" to "NO" in your BIOS setup. - Do I need to make any other BIOS adjustments? You should update your BIOS to the latest version available for your system. If your system has an option to enable ACPI, it should be enabled (typically under 'power management'). - Can ACPI damage my system? Under ACPI, the operating system is meant to be responsible for thermal management of the system. Our thermal management code has only been lightly tested, and many systems still ignore the OS and perform their own thermal management. You should monitor your system for any unexpected behaviour when using ACPI, not just overheating. - I pushed the power button, and my system shut down cleanly! Yes. ACPI brings some useful new features. 8) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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