On Sat, 28 Jun 2014, Pavel Machek wrote: > 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 M�ian <lukas@xxxxxxxxxxxxx> > > >> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> > > > > > > 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 . One possibility is not to use autosleep at all. The user program, instead of writing "on" to /sys/power/state to stay awake, would have to write "mem" to go to sleep when no more work remained to be handled. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
