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FreeBSD ACPI project



The acpi driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI standard. This support includes platform hardware discovery (superseding the PnP and PCI BIOS), as well as power management (superseding APM) and other features. ACPI core support is provided by the ACPI-CA reference implementation from Intel.

Information on using and debugging ACPI can be found in the handbook entry and man page.

If you are looking for the list of completed projects not located on this page, it can be found here.


High Priority Tasks

Task Responsible Last updated Priority Notes
Save/Restore PCI capabilities lists and MSI config space Nate Lawson August 3, 2006 In progress
Investigate disabling the LAPIC timer when using ACPI C2-3 states. Otherwise, the system hangs and no timer interrupts occur while idle. August 3, 2006 Not done
acpi_cpu — Finish work on CPU driver
_CST re-evaluation Nate Lawson December 4, 2004 Not done Needs testing/debugging
Fix shared user of a P_BLK (refcount) Nate Lawson December 4, 2004 Not done
Disable acpi_cpu taking over idling if only C1 available Nate Lawson December 4, 2004 Not done I still want to keep acpi_cpu in the loop on SMP systems so we should leave this as-is for now.
eject methods — implement eject and dynamic reprobing of acpi namespace Nate Lawson December 4, 2004 Needs testing

Medium Priority Tasks

Hotkey/backlight/sound generic driver -- Add a driver that generalizes the various device-specific ways of adjusting backlight, sound volume, hotkey support, etc. It should provide generic sysctls for these and attach to the hw-specific drivers (acpi_video, acpi_asus, acpi_toshiba, etc.) Not done

Low Priority Tasks

Implement X suspend/resume notification. Currently, the X server on FreeBSD is not notified of a suspend. We explicitly switch to a VTY on syscons before resume to get the server to save and then restore all the registers. This works for many systems but not if the display is left in less initialized at resume than the VTY switch code can handle. There is an interface (in the X server bsd_apm.c) for doing ioctls to find out about the suspend. First, check if this file is built on FreeBSD as it appears to only be built on NetBSD. Then implement the ioctls in both apm and acpi (on the apm compat device). Here is a patch to help the X file compile. For acpi, we do not want a user process dying to hold up the suspend process so implement the notification with a timeout. That is, if the kernel generates a APM_STANDBY_REQ notification and it doesn't receive a APM_IOC_STANDBY within say 5 seconds, continue the suspend process. This is needed for standby when X is not running, for instance, or when an emergency suspend is generated by a battery going critical. Not done
Examine the two video resume hacks (int 0x10, lcall 0xc000). Linux has begun to test calling the "lcall" VESA reset after PCI devices (including the video card) have been fully resumed, including power state set to PS0. This works for many Radeon cards but fails for others. We could implement this in vm86 calls from a proper video driver resume method. Investigate integrate the techniques used by the Radeontool port in video resume. Not done
ACPI-CA should really enable GPEs before calling \_WAK. Currently it does the opposite. This does not match the ACPI spec where \_WAK should be called after the system is up and running (\_BFS is what should be called as soon as possible after waking.) Not done
Potential ASL bug: We may need to work around some systems having the S3 object listed under the LPC bus device (PNP0A03) instead of root (\). This is ACPI-CA's responsibility. Not done
For systems that fail to power off, try using the suspend code (acpi_SetSleepState) instead. Not done
See if we can enable EC access early even if an ECDT is not present. The _INI method for some ECs accesses the EC region even though _REG has not been called since the region is not initialized yet. It is likely that Windows hard-codes the EC resources and enables the region before initializing the device even though this is not allowed by the spec. Not done
Implement reset register functionality for rebooting systems that lack a keyboard controller (see ACPI v2 FADT->ResetRegister). Not done
Be sure not to try to disable ACPI on systems that do not have SMI_CMD or ACPI_ENABLE/DISABLE values in the FADT. The ia64 machines specify ACPI-only (no legacy mode) so they have 0 for these values and we should not enable/disable ACPI on them. Doing so gives a "failed to switch modes" warning but no real problems, apparently. Not done
Check our implementation of AcpiOsDerivePciId(). It is probably not quite right. Compare against Linux. Not done
Run instructions on cpu0 for suspend/resume. We currently do this for shutdown in kern_shutdown.c:boot(). This will also be required for SMP cpufreq drivers that set the frequency via a CPU-specific MSR. Not done
Traverse local reference (scope) types in namespace when probing devices. Not done
Implement support for _PRS/_SRS and dependent functions. This will allow serial port configuration to occur. Not done
Add EC burst mode -- Code was written before to add burst mode to the EC. Unfortunately, it had to be disabled since it did not appear to work on all systems. Perhaps on some systems do not function correctly without burst mode, so it will be added back with some logic to fallback if it fails. Not done
Intel firmware seems to describe the PCI root bridge where chipset configuration space lives with _STA=="0x8". The spec says this means "functional, but not present". The current code ignores things that are "not present" ( msg). It is suggested that this should be handled by not attaching a driver to the device (i.e. bridge) but probe its children. Present on Big Sur and Bull systems. Not done
Re-work device wake setup to not be recursive. The acpi_wake_sysctl_walk() syscall has to call itself to handle child devices on other busses (PCI). This should probably be changed to be a DEVMETHOD. Not done
device_power -- Add a "power" argument to devctl(8) that allows a device to be set into various low power or off states. Not done
device_eject -- Add a devctl(8) program that has an "eject" argument. Allow users to eject various object names ("/dev/cdrom", "/mnt/flashdrive", "wi0", "pci0:2:0"). Call the appropriate _EJD and _EJx methods if appropriate. Warner Losh, John Baldwin, and Takanori Watanabe In progress
suspend to disk -- Implement a suspend/resume from disk mechanism. Possibly use the dump functions to dump pages to disk, then use ACPI to put the system in S4 or power-off. Resume would require changes to the loader to load the memory image directly and then begin executing again. Not done
HP/Toshiba Satellite driver -- Enabling the extra one-touch/multimedia keys, console blanking, battery and temperature reporting, etc. Get an idea of what is needed from the Linux OMKE project . Not done
ASL capture bootable CD-R -- Build a set of scripts to generate a bootable CD-R. It should have a GENERIC kernel and acpidump/iasl as well as all support libraries. Replace init with a script such that booting the CD generates an acpidump -t -d > machine.asl and dmesg > machine.dmesg in an MFS partition. Then burn this info to a second track on the CD-R. This will make an easy way to take a batch of CDRWs to the local computer store, place them in the CDRW drive, boot FreeBSD and get the ASL. Not done
ASL Explorer -- Graphical utility for examining the output of acpidump(8). Contact Nate Lawson for info about the design if you are interested in implementing this. Not done
Document acpi kernel interfaces -- Document the interfaces for drivers found in acpivar.h. Not done
KTR support for ACPI debug messages -- Use the KTR logging facility instead of printf for ACPI debugging messages. This would allow more verbose messages and fast dumping. Not done
Add support for the real-time clock (RTC) to use to wake or power-on systems at a certain time of day. Not done
Quiesce USB when no device is attached (see Linux UHCI) -- this would help such systems use C3 more, saving power with USB loaded. While at it, fix uhci suspend/resume. Not done