Messages in this thread | | | Date | Sat, 28 Jun 2014 22:04:10 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH] gpio_keys, twl4030-pwrbutton: stay awake for 1sec on resume |
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Hi!
> >> This gives the userspace (Replicant) a chance to fully handle the > >> pm_wakeup_event, before autosleep suspends the system alltogether > >> again. > >> > >> This fixes suspend/resume on the OpenPhoenux GTA04, in combination with > >> the Replicant 4.2.2 userspace, which needs to execute this to stay > >> awake: 'echo on > /sys/power/state' > >> > >> Signed-off-by: Lukas Märdian <lukas@goldelico.com> > >> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com> > > > > I'm sorry, but we should not be doing this. > > > > You basically put a delay in driver to work around userspace bug. > > Do you think it is a user-space bug if the kernel goes to sleep again > before giving user space any chance to react to an event?
Well, who says 1000msec is enough? Some userspace may need more. ... for example on PC when you keyboard-handling deamon is swapped out.
> And the msec parameter is described as: > > @msec: Anticipated event processing time (in milliseconds). > > Isn't calling pm_wakeup_event() with a non-zero msec the standard > method to handle this situation? And it is used in other drivers. E.g. in > _mmc_detect_change() or hub_suspend().
* Notify the PM core of a wakeup event whose source is @ws that will take * approximately @msec milliseconds to be processed by the kernel. If @ws is * not active, activate it. If @msec is nonzero, set up the @ws' timer to * execute pm_wakeup_timer_fn() in future.
Will take @msec milliseconds to be processed by the _kernel_. Yes, USB probing takes a lot of time in kernel. But you are using this parameter to wait for userspace...
> > There must be better > > solution.... > > I am not sure how it could look like.
Rafael, do you have any idea how this is supposed to work?
Original patch is at https://lkml.org/lkml/2014/4/10/156 . Pavel
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