On Friday, 6. February 2009, mark gross wrote: > On Wed, Feb 04, 2009 at 06:50:15PM -0800, Arve Hjønnevåg wrote: > > Signed-off-by: Arve Hjønnevåg <arve@xxxxxxxxxxx> > > --- > > Documentation/power/early-suspend.txt | 26 +++++++++++++++ > > include/linux/earlysuspend.h | 55 > > +++++++++++++++++++++++++++++++++ 2 files changed, 81 insertions(+), 0 > > deletions(-) > > create mode 100644 Documentation/power/early-suspend.txt > > create mode 100755 include/linux/earlysuspend.h > > > > diff --git a/Documentation/power/early-suspend.txt > > b/Documentation/power/early-suspend.txt new file mode 100644 > > index 0000000..8286d3a > > --- /dev/null > > +++ b/Documentation/power/early-suspend.txt > > @@ -0,0 +1,26 @@ > > +Early-suspend > > +============= > > + > > +The early-suspend api allows drivers to get notified when user-space > > writes to +/sys/power/request_state to indicate that the user visible > > sleep state should +change. A level controls what order the handlers are > > called in. Suspend +handlers are called in low to high level order, > > resume handlers are called in +the opposite order. > > + > > +Four levels are defined: > > +EARLY_SUSPEND_LEVEL_BLANK_SCREEN: > > + On suspend the screen should be turned off but the framebuffer must > > still be + accessible. On resume the screen can be turned back on. > > + > > +EARLY_SUSPEND_LEVEL_STOP_DRAWING: > > + On suspend this level notifies user-space that it should stop > > accessing the + framebuffer and it waits for it to complete. On resume > > it notifies user-space + that it should resume screen access. > > + Two methods are provided, console switch or a sysfs interface. > > + > > +EARLY_SUSPEND_LEVEL_DISABLE_FB: > > + Turn off the framebuffer on suspend and back on on resume. > > + > > +EARLY_SUSPEND_LEVEL_STOP_INPUT: > > + On suspend turn off input devices that are not capable of wakeup or > > where + wakeup is disabled. On resume turn the same devices back on. > > these levels names are domain and device profile centric. How can we > make these be applicable to more than the HTC dream? > > Why 4 levels? 4 seems like too many, but why stop at 4 why not 8? > The random number 4 comes from randomly pushing things from userspace to kernelspace. The only thing that I can see the kernel really needs to do is inform user space when it comes back from suspend. I never got a reply to why userspace should ever have to stop drawing to the frame buffer. If there is a valid reason for that, we might also need a blocking pre-suspend notifier, telling userspace that the device will suspend imediately. Uli -- ------- ROAD ...the handyPC Company - - - ) ) ) Uli Luckas Head of Software Development ROAD GmbH Bennigsenstr. 14 | 12159 Berlin | Germany fon: +49 (30) 230069 - 62 | fax: +49 (30) 230069 - 69 url: www.road.de Amtsgericht Charlottenburg: HRB 96688 B Managing director: Hans-Peter Constien _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
