On Oct 6, 2013 1:26 PM, "Gene Mosher" <<a href="mailto:gene@viewtouch.com">gene@viewtouch.com</a>> wrote: > > On 10/06/2013 12:00 PM, <a href="mailto:xorg-devel-request@lists.x.org">xorg-devel-request@lists.x.org</a> wrote: >> >> Message: 2 >> Date: Sun, 06 Oct 2013 11:17:13 -0700 >> From: Keith Packard <<a href="mailto:keithp@keithp.com">keithp@keithp.com</a>> >> To: Mark Kettenis <<a href="mailto:mark.kettenis@xs4all.nl">mark.kettenis@xs4all.nl</a>> >> Cc: <a href="mailto:xorg-devel@lists.freedesktop.org">xorg-devel@lists.freedesktop.org</a>, <a href="mailto:kaccardi@gmail.com">kaccardi@gmail.com</a>, >> <a href="mailto:arjan@linux.intel.com">arjan@linux.intel.com</a> >> Subject: Re: [PATCH] Close non-keyboard devices on DPMS off >> Message-ID: <<a href="mailto:86siwe463a.fsf@miki.keithp.com">86siwe463a.fsf@miki.keithp.com</a>> >> Content-Type: text/plain; charset="utf-8" >> >> Mark Kettenis <<a href="mailto:mark.kettenis@xs4all.nl">mark.kettenis@xs4all.nl</a>> writes: >> >>> > Is that really desirable? >> >> It has a couple of benefits -- the first is that touch screens and touch >> pads often get input while your laptop screen is closed; this prevents >> that from waking up the X server. >> >> The second is that turning off input devices can allow the system to >> shut down USB resources and save a bunch of power. I posted the patch so >> that we could get measurements of the power savings. >>> >>> > For me, moving the mouse has always been the most natural way to wake >>> > up the screen. >> >> Yeah, that's the usual way I wake my machine up as well. However, if you >> try this on an OS X machine, you'll find that only the keyboard will >> wake the machine up. So, it's not a universal policy at least. >> >>> > And I can imagine that touching the screen is the most >>> > natural way to do it on a device with a touchscreen. Such devices >>> > might not even have keyboard. >> >> It's hard to imagine a device without *any* keys, but it's certainly >> possible. The trick would be to figure out how to detect this >> automatically; my machine lists six "keyboard" devices: >> >> ? Power Button id=6 [slave keyboard (3)] >> ? Power Button id=8 [slave keyboard (3)] >> ? Sleep Button id=9 [slave keyboard (3)] >> ? FaceTime HD Camera (Built-in) id=11 [slave keyboard (3)] >> ? Apple Inc. Apple Internal Keyboard / Trackpad id=12 [slave keyboard (3)] >> ? Video Bus id=7 [slave keyboard (3)] >> >> I think the interesting part here is the potential for power savings >> while the screen is blanked; getting some idea of how much closing the >> other devices is worth would be really helpful in figuring out when to >> make this choice. >> >> -- >> <a href="mailto:keith.packard@intel.com">keith.packard@intel.com</a> > > Keith, why do you want to fix something that isn't broken, by breaking it? You say it's hard to imagine a device without *any* keys, well such 'devices' are the ONLY kind of devices I ship running the X server. These are not battery operated machines so the advantage of saving power doesn't exist. What is wrong with waking up a touchscreen driven computer by touching the screen? There's nothing wrong with it! > > --Gene Mosher You should always try to save power, even if you are using electricity instead of a battery. Its the right thing to do.