PERFORCE change 43464 for review

[John Baldwin]

On 09-Dec-2003 M. Warner Losh wrote:
> In message: <XFMail.20031208155247.jhb at FreeBSD.org>
>             John Baldwin <jhb at freebsd.org> writes:
>: 
>: On 05-Dec-2003 Nate Lawson wrote:
>: > On Fri, 5 Dec 2003, John Baldwin wrote:
>: >> Change 43464 by jhb at jhb_blue on 2003/12/05 12:59:01
>: >>
>: >>      More updates.  Closer to working than I thought.  In theory
>: >>      PCI devices should all just work now.
>: > 
>: > This handles PCI.  Are you ok with me adding the call to
>: > acpi_pwr_switch_consumer() for non-PCI devices like the embedded
>: > controller?  I think we need to do this at the top \\_SB level.  I'm a bit
>: > confused as to the handoff between the general tree walk and the ACPI-PCI
>: > driver though.
>: 
>: It won't hurt to switch a device on twice.  It should be ok to
>: do a top-level tree walk of all device objects and turn them on
>: before probing child devices I think.  ACPI shouldn't turn off
>: devices that don't probe like PCI does though because ACPI has
>: duplicate objects of things like the entire PCI device tree. :-/
> 
> Actually, there can be times when you don't want to turn on devices at
> all.  Walking the whole tree turning them on might be the wrong to
> do...
> 
> Sometimes I think that things in the newbus tree should have a pointer
> to the acpi power methods that are used in coordination with the bus
> code that is 'activating' the device before the 'probe' and 'attach'
> happens.

I think having a 'bus_set_power_state()' method in the bus layer
and having device_probe_and_attach() do 'bus_set_power_state(child, ON)'
would be sufficient.  ACPI busses would then perform the correct hooks
via their bus_set_power_state() methods.

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/