On Wed, 25 Apr 2012 15:26:03 +1000 NeilBrown <neilb@xxxxxxx> wrote: > On Tue, 24 Apr 2012 22:09:19 -0700 Dmitry Torokhov > <dmitry.torokhov@xxxxxxxxx> wrote: > > > Hi Neil, > > > > On Wed, Apr 25, 2012 at 12:21:39PM +1000, NeilBrown wrote: > > > > > > If we press and release the power button before the press interrupt is > > > handled - as can happen on resume - we lose the press event so the > > > release event is ignored and we don't know what happened to cause the > > > wakeup. > > > > What kind of latency do you observe? > > When I have debugging enabled, hundreds of milliseconds. > > When I don't have debugging enabled ... it doesn't tell me, but I'm fairly > sure it is several tens of milliseconds and the button press can be quicker > than that. > > If it will help I can try to instrument the driver and get some timings. I added a bit of tracing. It looks like a fast button press typically shows about 120ms between 'press' and 'release', though I have seen as low as 70ms. When I don't have PM_DEBUG debugging on, the 'press' interrupt gets handled in about 14ms. So it seems likely that the times that I suffered from the problem and so wrote the patch, I had PM_DEBUG enabled which slows resume down quite a lot. So I cannot make a strong case for these patches. However I think it is safer to have them than not :-) Thanks, NeilBrown
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