Hi Richard, On Friday 19 October 2007, Richard Purdie wrote: > On Tue, 2007-10-16 at 10:34 -0400, Dmitry Torokhov wrote: > > On 10/16/07, Kristoffer Ericson <[EMAIL PROTECTED]> wrote: > > > This is mainly an embedded issue, but I feel it's quite important. > > > It should apply to other devices also like for example Zaurus > > > branches (those with keyboard and designated power button). > > There was a long discussion thread about this a while back. There were a > lot of differing views but in the end no patch to fix up power.c to do > anything was accepted. The Zaurus was the reason I raised the issue. > > It seems power.c was recently removed as it was dead code.
That's because nothing in mainline was using it. > > > > So in short: > > > 1. Does mainline policy allow static power button events inside kernel > > > (power button == suspend/resume)? > > > Why/Why Not? > > > > Could it be that you may want to prevent suspend from happening? Or > > delay it until system completes some important operation? Do something > > else, like cleanly disconnect your network connections? With actual > > handling done in userspace it's all possible. With suspend done > > directly in kernel it is much harder and couples input subsystem with > > power management too tightly. > > > > However if you are dead-set on doin it in kernel you coudl register an > > input_handler in your platform PM code and it will attach to your > > keyboard. Look for power.c module in older kernels for example. > > The proposed changes to power.c were to hook it into things like APM as > a "user" event so the power button triggered a suspend event but > anything in userspace needing to know about (or veto) it could do so. > > > > 2. Seeing as my knowledge about this area isn't the best I would > > > appreciate all opinions on the subject from the gurus. > > > > Richard Purdie I think might have some pointers. > > Currently I still patch this functionality into the Zaurus kernels > (basically by resurrecting power.c with the patches I used to apply to > it added in): > > http://www.rpsys.net/openzaurus/patches/input_power-r9.patch > > This works for 2.6.23 but doesn't seem to work in 2.6.23-git9. I've not > looked into why yet. > > In the current climate, this will never make mainline kernels so I will > be considering other options such as adding support into something like > OHM. As yet, I've not found the time to do that and since the above > patch works and is relatively easy to maintain... > I think power.c as it was is not a good idea. Generic code does not know the best way of shutting down/suspending a certain box. However having an arch- (or even board-) specific version of power.c that pligs directl and poperly into appropriate PM mechanism makes more sense. If certain platforms need it I don't see a reason to prevent them from doing so. -- Dmitry - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
