[PATCH wayland-protocols v3] Add screensaver idle inhibitor protocol

Pekka Paalanen ppaalanen at gmail.com
Fri Jun 3 08:41:12 UTC 2016


On Thu, 2 Jun 2016 14:33:42 -0700
Bryce Harrington <bryce at osg.samsung.com> wrote:

> On Wed, May 18, 2016 at 04:11:39PM +0300, Pekka Paalanen wrote:
> > On Thu, 24 Mar 2016 11:14:33 -0700
> > Bryce Harrington <bryce at osg.samsung.com> wrote:
> >   
> > > This interface allows disabling of screensaver/screenblanking on a
> > > per-surface basis.  As long as the surface remains visible and
> > > non-occluded it blocks the screensaver, etc. from activating on the
> > > output(s) that the surface is visible on.
> > > 
> > > To uninhibit, simply destroy the inhibitor object.  
> > 
> > Hi,
> > 
> > ok, that sounds good.
> >   
> > > Signed-off-by: Bryce Harrington <bryce at bryceharrington.org>
> > > ---
> > > v2: Rename protocol to idle-inhibit
> > >  + Use "idle" rather than "screensaver".  People likely to be interested
> > >    in this protocol would know the difference between "blanking", "dpms",
> > >    and literal "screensavers", so don't lead them to think that this only
> > >    deals with the latter.  The protocol addresses all manner of idle
> > >    behaviors, so is a more accurate name.
> > >  + Standardize nomenclature to "idle-manager" and "inhibitor" for clarity.
> > >    "inhibition_inhibit" was just too cumbersome.  
> > 
> > Alright!
> >   
> > > 
> > >  Makefile.am                                        |  1 +
> > >  unstable/idle-inhibit/README                       |  4 ++
> > >  unstable/idle-inhibit/idle-inhibit-unstable-v1.xml | 78 ++++++++++++++++++++++
> > >  3 files changed, 83 insertions(+)
> > >  create mode 100644 unstable/idle-inhibit/README
> > >  create mode 100644 unstable/idle-inhibit/idle-inhibit-unstable-v1.xml
> > > 
> > > diff --git a/Makefile.am b/Makefile.am
> > > index 5926a41..ac497d8 100644
> > > --- a/Makefile.am
> > > +++ b/Makefile.am
> > > @@ -5,6 +5,7 @@ unstable_protocols =								\
> > >  	unstable/text-input/text-input-unstable-v1.xml				\
> > >  	unstable/input-method/input-method-unstable-v1.xml			\
> > >  	unstable/xdg-shell/xdg-shell-unstable-v5.xml				\
> > > +	unstable/idle-inhibit/idle-inhibit-unstable-v1.xml	\
> > >  	$(NULL)
> > >  
> > >  nobase_dist_pkgdata_DATA =							\
> > > diff --git a/unstable/idle-inhibit/README b/unstable/idle-inhibit/README
> > > new file mode 100644
> > > index 0000000..396e871
> > > --- /dev/null
> > > +++ b/unstable/idle-inhibit/README
> > > @@ -0,0 +1,4 @@
> > > +Screensaver inhibition protocol
> > > +
> > > +Maintainers:
> > > +Bryce Harrington <bryce at osg.samsung.com>
> > > diff --git a/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml b/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml
> > > new file mode 100644
> > > index 0000000..a8c8a85
> > > --- /dev/null
> > > +++ b/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml
> > > @@ -0,1 +1,78 @@
> > > +<?xml version="1.0" encoding="UTF-8"?>
> > > +<protocol name="idle_inhibit_unstable_v1">
> > > +
> > > +  <copyright>
> > > +    Copyright © 2015-2016 Samsung Electronics Co., Ltd
> > > +
> > > +    Permission is hereby granted, free of charge, to any person obtaining a
> > > +    copy of this software and associated documentation files (the "Software"),
> > > +    to deal in the Software without restriction, including without limitation
> > > +    the rights to use, copy, modify, merge, publish, distribute, sublicense,
> > > +    and/or sell copies of the Software, and to permit persons to whom the
> > > +    Software is furnished to do so, subject to the following conditions:
> > > +
> > > +    The above copyright notice and this permission notice (including the next
> > > +    paragraph) shall be included in all copies or substantial portions of the
> > > +    Software.
> > > +
> > > +    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> > > +    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> > > +    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> > > +    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> > > +    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> > > +    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> > > +    DEALINGS IN THE SOFTWARE.
> > > +  </copyright>
> > > +
> > > +  <interface name="zwp_idle_inhibit_manager_v1" version="1">
> > > +    <description summary="control behavior when display idles">
> > > +      This interface permits inhibiting the idle behavior such as screen
> > > +      blanking, locking, and screensaving.  The client binds the idle manager
> > > +      globally, then creates idle-inhibitor objects for each surface.
> > > +
> > > +      Warning! The protocol described in this file is experimental and
> > > +      backward incompatible changes may be made. Backward compatible changes
> > > +      may be added together with the corresponding interface version bump.
> > > +      Backward incompatible changes are done by bumping the version number in
> > > +      the protocol and interface names and resetting the interface version.
> > > +      Once the protocol is to be declared stable, the 'z' prefix and the
> > > +      version number in the protocol and interface names are removed and the
> > > +      interface version number is reset.
> > > +    </description>
> > > +
> > > +    <request name="create_inhibitor">
> > > +      <description summary="create a new inhibitor object">
> > > +	Create a new inhibitor object associated with the given surface.
> > > +      </description>
> > > +      <arg name="id" type="new_id" interface="zwp_idle_inhibitor_v1"/>
> > > +      <arg name="surface" type="object" interface="wl_surface"
> > > +	   summary="the surface that inhibits the idle behavior"/>
> > > +    </request>  
> > 
> > This interface is missing a destructor. It is the only way the
> > compositor could destroy the wl_resource before the client disconnects.
> > 
> > All interfaces need a way to destroy the object.
> >   
> > > +  </interface>
> > > +
> > > +  <interface name="zwp_idle_inhibitor_v1" version="1">
> > > +    <description summary="context object for inhibiting idle behavior">
> > > +      An idle inhibitor prevents the output that the surface is visible on  
> > 
> > "the associated surface", to be crystal clear.
> >   
> > > +      from being blanked, dimmed, locked, set to power save, or otherwise
> > > +      obscured due to lack of user interaction.  Any active screensaver
> > > +      processes are also temporarily blocked from displaying.
> > > +
> > > +      If the surface is destroyed, disabled, becomes occluded or otherwise  
> > 
> > What does "disabled" mean? Are you looking for "unmapped"?
> > 
> > Should we say "completely occluded"?  
> 
> I am not certain that we should limit it to that, in case a compositor
> wanted to have a partial occlusion state be reason for not honoring
> inhibition requests.  But it's hard to conceptualize the potential use
> cases here.

Hi,

right, it might be better to list the things you can be explicit about
and leave rest for a vague or-any-other-thing.

It might help to step back and think how you would explain to another
person what you actually want to mean here. It will be a verbose
description that should be much easier to compress into a spec wording
afterwards than to come up with spec wording initially. I do that
when I realize I'm struggling with wording.

> > > +      loses visibility, the screen behavior is restored to normal; if the  
> > 
> > I'd change "the screen behavior is restored to normal" to "the
> > inhibitor becomes ineffective". Restoring to normal is a bit vague, and
> > might not even be true if there are other inhibitors in effect.  
> 
> Hmm, how about "the inhibition request will not be honored by the
> compositor?"

Sounds fine, though I'd use "inhibitor" rather than "inhibition
request" since we are not talking about a protocol message here. It
would be good to restrict the use of "request" as a noun to
client-to-server protocol messages to avoid confusion.

> > > +      surface subsequently regains visibility or is unoccluded, the inhibitor
> > > +      takes effect once again.  
> > 
> > Strike "or is unoccluded", it's already covered by "regains
> > visibility", right?
> >   
> > > +
> > > +      Note that in the case of a compound window (a surface with
> > > +      sub-surfaces), a separate inhibitor object may be needed for each
> > > +      wl_surface.  
> > 
> > In case of sub-surfaces, inheriting inhibitor effects would be much
> > better than having to explicitly set every wl_surface, as pointed out
> > in earlier reviews. I should have given that comment the first time.
> >   
> > > +    </description>
> > > +
> > > +    <request name="destroy" type="destructor">
> > > +      <description summary="destroy the idle inhibitor object">
> > > +	This restores screensaver/blanking/et al behaviors to their normal
> > > +	state and destructs the idle inhibitor object.  
> > 
> > Or just: "This removes the inhibitor effect from the associated
> > wl_surface."
> >   
> > > +      </description>
> > > +    </request>
> > > +
> > > +  </interface>
> > > +</protocol>  
> > 
> > Otherwise just wording nitpicks, but two things I would like to see
> > corrected:
> > - the missing destructor
> > - interaction with sub-surfaces  
> 
> Apart from the questions above I've incorporated the other feedback in
> the v3 patch.


Thanks,
pq
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