[Spice-devel] Spice bug62033, Gnome bug 680195 rework: new inhibitors for desktop effects

[Bastien Nocera]

On Thu, 2013-10-31 at 14:44 +0400, Fedor Lyakhov wrote:
> Hi Bastien,
> 
> I'm working on a bug/enhancement for Spice reported by Zeeshan:
> https://bugs.freedesktop.org/show_bug.cgi?id=62033 (Means to detect
> local-only). It is related to Gnome bug
> https://bugzilla.gnome.org/show_bug.cgi?id=680195 (Disable animations
> when on slow VNC or spice)
> 
> We've discussed possible solutions for this issue in the spice-devel
> mailing list (the last message in the thread -
> http://lists.freedesktop.org/archives/spice-devel/2013-September/014562.html).
> 
> Summary of the issue:
> Need to disable desktop effects (animation, wallpaper, font smoothing)
> when user is connected via Spice over slow network.
> 
> Proposed solution:
> (i) Use existing "--spice-disable-effects" option which works for
> Windows guests already: implement such functionality for Linux guests.
> The feature can be invoked from oVirt, so it will be useful.
> (ii) Implement the feature via inhibitors: Spice vdagent to call
> DE-provided inhibitor-styled D-Bus API to inhibit animation, wallpaper
> and font smoothing. This way the feature will be supported at any DE
> which provides such API - hopefully we can get support for Gnome3, KDE
> (5?) and Unity (minimum list).
> 
> Does the solution seem reasonable for you? Any comments would be appreciated.

The only thing that spice needs to do is export the fact that it's
running on a slow link. gnome-settings-daemon will take care of reading
that and acting accordingly.

There's no need for spice to know what the desktop environment will make
of it.

> I have few additional questions:
> 1. I know you have been involved into Inhibitor API discussions with
> KDE folks about a year ago (I've seen only
> http://lists.freedesktop.org/pipermail/xdg/2012-November/012580.html
> thread). Could you please summarize the current status of this API in
> Gnome and maybe KDE (including all inhibitors, not only screen saver)?
> I cannot find any relevant documentation about this...

The specification website is currently broken, but that's what I had:
http://people.freedesktop.org/~hadess/idle-inhibition-spec/index.html

It's only for enabling idle inhibition, nothing else.

> 2. What do you think about adding new inhibitors for our needs? Where
> should I start from? Is the implementation need to be added to
> gnome-desktop-settings?

It's a system plumbing issue, and inhibitors are for applications, so
I'd be against it.

Cheers