Re: [PATCH] lis3lv02d: provide means to disable polled inputinterface

[Marcin Derlukiewicz]

Dnia 16-04-2010 o 14:00:15 <samu.p.onkalo@xxxxxxxxx> napisaÅ(a):

> > -----Original Message-----
> > From: ext Marcin Derlukiewicz [mailto:marcin@xxxxxxxxxxxxxxx]
> > Sent: 16 April, 2010 14:42
> > To: Jiri Kosina; Ãric Piel
> > Cc: Andrew Morton; Onkalo Samu.P (Nokia-D/Tampere); Pavel Machek; lm-
> > sensors@xxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH] lis3lv02d: provide means to disable polled input
> > interface
> >
> > Dnia 09-04-2010 o 15:32:59 Jiri Kosina <jkosina@xxxxxxx> napisaÅ(a):
> >
> > > On Fri, 9 Apr 2010, Ãric Piel wrote:
> > >
> > > > > 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?
> > >
> > > Marcin originally reported this to me.
> > >
> > > Marcin, could you please check 'lsof' output to see whether the
> > joystick
> > > interface has been open by some application?
> > >
> > > Thanks,
> >
> > sorry for the delay, had a crunch time
> >
> > here is the link for this lsof:
> > https://bugzilla.novell.com/attachment.cgi?id=354953
>
> Could you check what is the polling period of the device.
> something like:
> cat /sys/devices/platform/lis3lv02d/input/input9/poll
>
> it is current polling period in milliseconds. 0 disables polling.
>
> -Samu

I think that on my system this is /sys/devices/platform/lis3lv02d/rate
but i may be wrong. Anyway it contains 40 as a number.

Marcin.
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