ubuntu-phone team mailing list archive

[Alberto Mardegan <alberto.mardegan@xxxxxxxxxxxxx>]

On 10/25/2013 08:48 PM, Thomas Voß wrote:
> One thing that strikes me: Instead of trying to solve the problem a
> lot of "won't work" statements are made in this thread, going along
> with a request for removing all of the lifecycle policies. And to be
> clear: With strict policies in place, it is always possible to find an
> example that breaks. So I think we can stop collecting breaking
> examples here.

I think that Ubuntu should strive to do *better* than other platforms,
not equal or worse. So, given that we are at the early stages and we are
still in a position to correct the design and improve the
implementations, we should spend some time to think of use cases which
we don't support with the current design, and address them.

Especially given that it might not be easy to change this stuff in the
future.

>> Yes and no. As I wrote before in this thread, in some cases it's
>> possible to detect when an application will need to run or can be
>> killed. We don't have to allow all applications to run in the
>> background. But why not let a navigation application declare in its
>> manifest file that it wants to be left running if it's defocused while
>> the GPS is on?
> 
> Because that is an open invite to any app developer to leverage that
> way out, too. We do not do install time application permission
> verification by the user for a good reason.

I think we are misunderstanding; I'm not saying that the user should be
asked (at install time or at run time) for granting a permission. There
would be a policy groups "background_gps", "background_music" which the
app developer can declare in its manifest file. Then, if the application
is defocused while it's using the GPS or playing music, it wouldn't be
stopped. If it's not using the GPS or playing music, it will be stopped.
It seems much simpler to me, and I don't see what could go wrong here.

>> As for GPU resources, Qt can release all of them when the window is not
>> exposed, if told to.
> 
> Hmmm, people said that about cooperative multi-tasking, too: Sure, the
> app will happily give up its timeslice (tm).

You are right that we cannot depend on this. But the display server can
know the amount of GPU resources that each application is using, and
kill those which use more of them; in this way, an application which
properly releases all the GPU resources would probably be saved.
Anyway, I now realize that this is actually not the issue we were
discussing (this is about killing, while the discussion is about
stopping), so we can forget about this second topic. :-)

Ciao,
  Alberto