cvs commit: src/sys/dev/pci pci.c

Nate Lawson nate at
Sun Sep 18 10:09:35 PDT 2005

Joao Barros wrote:
> On 9/11/05, Warner Losh <imp at> wrote:
>>imp         2005-09-11 19:28:31 UTC
>>  FreeBSD src repository
>>  Modified files:        (Branch: RELENG_6)
>>    sys/dev/pci          pci.c
>>  Log:
>>  Change the default of pci_do_powerstate to 0, per request from re at .
>>  The number of raid controllers that violate the WHQL seems to be
>>  growing in number and not isolated to old versions as previously
>>  thought.  Though the numbers of these seen in the wild is still
>>  relatively small, they hang the system when parts of their devices are
>>  powered down.  The one area that these parts appear often are in the
>>  higher end servers.  As such, be conservative about powering down
>>  devices that have no driver attached by default.  Until a better
>>  approach is proven in current, this is the prudent choice.
>>  Laptop users wishing the benefits of powering down devices with no
>>  drivers will now need to set hw.pci.do_powerstate=1 in their
>>  /boot/loader.conf file.  Some users will have devices that will
>>  prevent this setting (hence the need to make it default 0).
>>  Approved by: re@ (scottl)
>>  Revision   Changes    Path
>>  +2 -2      src/sys/dev/pci/pci.c
> I was reading the Release Notes for 6.0 on
> and noticed:
> 2.2.2 Hardware Support
> The acpi(4) driver now turns the ACPI and PCI devices off or to a
> lower power state when suspending, and back on again when resuming.
> This behavior can be disabled by setting the debug.acpi.do_powerstate
> and hw.pci.do_powerstate sysctls to 0.
> Given this is the same tunable you changed back to 0 by default, does
> that "when resuming" has anything to do with this last commit? If so,
> it could still be mentioned the other way around, allowing people
> wanting to, to enable the tunable :)

You bring up a different point also, which is that ACPI should probably 
be set to match this same default for release.


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