Re: [RFC PATCH 6/9] ui/gtk: Add a new parameter to assign connectors/monitors to GFX VCs

[Kim, Dongwon]

Hi Markus,

So I've worked on the description of this param. Can you check if this new 
version looks ok?

# @connectors:  List of physical monitor/connector names where the GTK
#           windows containing the respective graphics virtual consoles (VCs)
#           are to be placed. Index of the connector name in the array directly
#           indicates the id of the VC.
#           For example, with "-device gtk,connectors.0=DP-1, 
connectors.1=DP-2",
#           a physical display connected to DP-1 port will be the target monitor
#           for VC0 and the one on DP-2 will be the target for VC1. If there is
#           no connector associated with a VC, then that VC won't be placed 
anywhere
#           before the QEMU is relaunched with a proper connector name set for 
it.
#           If a connector name exists for a VC but the display cable is not 
plugged
#           in when guest is launched, the VC will be just hidden but will show 
up
#           as soon as the cable is plugged in. If a display is connected in 
the beginning
#           but later disconnected, VC will immediately be hidden and guest 
will detect
#           it as a disconnected display. This option does not force 1 to 1 
mapping
#           between the connector and the VC, which means multiple VCs can be 
placed
#           on the same display but vice versa is not possible (a single VC 
duplicated
#           on a multiple displays)
#           (Since 8.1)

Thanks,
DW

On 6/20/2023 10:51 PM, Markus Armbruster wrote:

> Dongwon Kim <dongwon.kim@intel.com> writes:
>
> > From: Vivek Kasireddy <vivek.kasireddy@intel.com>
> >
> > The new parameter named "connector" can be used to assign physical
> > monitors/connectors to individual GFX VCs such that when the monitor
> > is connected or hotplugged, the associated GTK window would be
> > moved to it. If the monitor is disconnected or unplugged, the
> > associated GTK window would be hidden and a relevant disconnect
> > event would be sent to the Guest.
> >
> > Usage: -device virtio-gpu-pci,max_outputs=2,blob=true,...
> >         -display gtk,gl=on,connectors.0=eDP-1,connectors.1=DP-1.....
> >
> > Cc: Gerd Hoffmann <kraxel@redhat.com>
> > Cc: Daniel P. Berrangé <berrange@redhat.com>
> > Cc: Markus Armbruster <armbru@redhat.com>
> > Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
> > Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> > Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
> [...]
>
> > --- a/qapi/ui.json
> > +++ b/qapi/ui.json
> > @@ -1315,13 +1315,22 @@
> >   # @show-menubar: Display the main window menubar.  Defaults to "on".
> >   #     (Since 8.0)
> >   #
> > +# @connectors:  List of physical monitor/connector names where the GTK
> > +#               windows containing the respective graphics virtual consoles
> > +#               (VCs) are to be placed. If a mapping exists for a VC, it
> > +#               will be moved to that specific monitor or else it would
> > +#               not be displayed anywhere and would appear disconnected
> > +#               to the guest.
> > +#               (Since 8.1)
> Please format like
>
>     # @connectors: List of physical monitor/connector names where the GTK
>     #     windows containing the respective graphics virtual consoles
>     #     (VCs) are to be placed.  If a mapping exists for a VC, it will
>     #     be moved to that specific monitor or else it would not be
>     #     displayed anywhere and would appear disconnected to the guest.
>     #     (Since 8.1)
>
> to blend in with recent commit a937b6aa739 (qapi: Reformat doc comments
> to conform to current conventions).
>
> The meaning of @connectors is less than clear.  The phrase "If a mapping
> exists for a VC" suggests it is a mapping of sorts.  "List of physical
> monitor/connector names" indicates it maps to physical monitor /
> connector name.  What does it map from?  VC number?  How are VCs
> numbered?  Is it the same number we use in QOM /backend/console[NUM]?
>
> Using a list for the mapping means the mapping must be dense, e.g. I
> can't map #0 and #2 but not #1.  Is this what we want?
>
> The sentence "If a mapping exists" confusing has a dangling else
> ambiguity of sorts.  I can interpret it as
>
>      If a mapping exists for a VC:
>          the window will be moved to that specific monitor
>          or else it would not be displayed anywhere and would appear ...
>
> or as
>
>      If a mapping exists for a VC:
>          the window will be moved to that specific monitor
>      or else it would not be displayed anywhere and would appear ...
>
> I think we have three cases:
>
> 0. No mapping provided
>
> 1. Mapping provided, and the named monitor / connector exists
>
> 2. Mapping provided, and the named monitor / connector does not exist
>
> We can go from case 1 to 2 (disconnect) and vice versa (connect) at any
> time.
>
> Please spell out behavior for each case, and for the transitions between
> case 1 and 2.
>
> > +#
> >   # Since: 2.12
> >   ##
> >   { 'struct'  : 'DisplayGTK',
> >     'data'    : { '*grab-on-hover' : 'bool',
> >                   '*zoom-to-fit'   : 'bool',
> >                   '*show-tabs'     : 'bool',
> > -                '*show-menubar'  : 'bool'  } }
> > +                '*show-menubar'  : 'bool',
> > +                '*connectors'    : ['str'] } }
> >   
> >   ##
> >   # @DisplayEGLHeadless:
> [...]