Fighting for the power.

M. Warner Losh imp at
Thu May 7 06:14:20 UTC 2009

In message: <3a142e750905040240g58152e69p6fcb797a5e026426 at>
            "Paul B. Mahol" <onemda at> writes:
: On 5/4/09, Alexander Motin <mav at> wrote:
: > 2. PCI devices
: > PCI bus provides method to control device power. For example, I have
: > completely no use for my FireWire controller and most of time - EHCI USB
: > controller. Disabling them allows me to save about 3W of power. To
: > disable all unneeded PCI devices you should build kernel without their
: > drivers and add to loader.conf:
: > hw.pci.do_power_nodriver=3
: > To enable devices back all you need to do is just load their drivers as
: > modules.
: Unloading modules doesnt put them back into into D3 state.
: You are forced to load some another module again to put wanted device
: into D3 state.

It should.  If it isn't, that's a bug.


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