Re: [PATCH] Leave runtime suspended devices off at system resume

[Greg KH <greg@kroah.com>]

On Wed, May 26, 2004 at 02:43:19PM -0700, Todd Poynor wrote:
> Currently all devices are resumed at system resume time, including any
> that were individually powered off ("at runtime") prior to the system
> suspend.  In certain cases it can be nice to force back on individually
> suspended devices, such as the display, but hopefully this policy can be
> left up to userspace power managers; the kernel should probably honor
> the settings previously made by userspace/drivers.  This seems
> preferable to requiring a power-conscious system to re-suspend devices
> after a system resume; furthermore, for certain platforms (such as
> XScale PXA27X) there can be disastrous consequences of powering up
> devices when the system is in a state incompatible with operation of the
> device.
> 
> Suggested patch does this:
> 
> (1) At system resume, checks power_state to see if the device was
> suspended prior to system suspend, and skips powering on the device if
> so.
> 
> (2) Does not re-suspend an already-suspended device at system suspend
> (using a different method than is currently employed, which reorders the
> list, see #3).
> 
> (3) Preserves the active/off device list order despite the above changes
> to suspend/resume behavior, to avoid dependency problems that tend to
> occur when the list is reordered.

Nice, that looks good.

Applied, thanks.

greg k-h