Re: CVS commit: src/sys/kern

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Thu, Feb 21, 2008 at 06:48:36PM +0100, Manuel Bouyer wrote:
> On Thu, Feb 21, 2008 at 04:58:20PM +0100, Joerg Sonnenberger wrote:
> > On Thu, Feb 21, 2008 at 02:57:54PM +0100, Manuel Bouyer wrote:
> > > We had a similar issues some time ago, where disk would be spun down on
> > > reboot or halt without powerdown. My conclusion was that drivers needs to
> > > know what kind of suspend we're doing (suspend, reboot, halt, poweroff) to
> > > take appropriate action (which may not always be to power off the device).
> > > At this time, the disk issue was fixed by a hack using global variable.
> > > But I still believe drivers needs to get more informations from PMF to
> > > know what's going on.
> > 
> > I still haven't seen any other example that needs to distinguish between
> 
> I think Matthias has given some. You seems to assume the firmware can
> power on devices that we powered off during shutdown, and that's probably
> not always true. For example, I don't think the Sun Openfirmware
> expects PCI devices to be in D3 state when the OS gives back control after
> a shutdown -h. 

reboot/halt and powerdown are not different in how they handle PCI
devices. Note: shutdown path in general and how to handle that is a
different discussion. Being able to distinguish in the shutdown path
from whether this is a reboot/halt *or* a powerdown is quite different.
I have not seen examples for where the latter matters beside the disk
drivers.

Joerg