Re: [PATCH][RFC] usbhid: enable autosuspend for internal devices

From: Oliver Neukum
Date: Mon Jun 29 2015 - 07:38:33 EST


On Mon, 2015-06-29 at 13:16 +0200, Jiri Kosina wrote:
> On Mon, 29 Jun 2015, Oliver Neukum wrote:
>
> > > Last time we were testing this, autosuspend for USB HID devices was quite
> > > a disaster.
> > >
> > > Do you have any idea whether udev developers tested the "autosuspend on by
> > > default for USB HID devices" on reasonable set of devices?
> > >
> > > The culrpits that I remember from top of my head (it's been long time
> > > ago):
> > >
> > > - the LEDs for suspended device go off. This is very confusing at least on
> > > keyboards, and brings really bad user experience
> >
> > That is a bug. hidinput_count_leds() is supposed to prevent that.
>
> This is a HW property and nothing kernel can do about. I am not saying it
> doesn't bring the LEDs up to a proper state again once auto-resumed. But I
> hate the LEDs going off a few seconds after I stop typing (i.e. once the
> keyboard gets auto-suspended).

That is the point. Unless you give the option to override, they
shouldn't autosuspend.

Regards
Oliver



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