Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 09 Apr 2010 15:29:53 +0200 | From | Éric Piel <> | Subject | Re: [PATCH] lis3lv02d: provide means to disable polled input interface |
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On 09/04/10 14:56, Jiri Kosina wrote: > lis3lv02d driver creates emulated joystick interface for events reported > by the sensor. > Because of HW, this has to be implemented as polled input device, with > 20Hz frequency. > > This is reported to create 20% CPU usage increase (and proportionaly higher > power consumption) just for the ipolldevd kernel thread (which is used > to read the sensor). > > As most users probably only use the freefall functionality of the driver > and not the joystick interface, provide means for disabling the registration > of joystick device altogether via module parameter. > (I'd rather make it default to 0, but this will break backwards compatibility). Are you saying there is a 20% CPU usage even when the joystick interface is not open? This should not happen (and this is not happening on my laptop). The polling should happen only when a userspace app opens the joystick interface (like running neverball).
So I'd tend to think it's more due to a misconfiguration of the system (like xserver using the joystick interface as a pointer device) or it's a bug in the way we set up the polling. Could you investigate and let me know?
Cheers, Eric
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