Add a new D-Bus API that uses the state from GetCurrentState to
configure high level monitors, instead of low level CRTCs and
connectors. So far persistent configuration is not implemented, as
writing to the configuration store is still not supported.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
Let the backends decide whether to just rebuild a derived state, or use
the NULL config to rebuild an empty logical state.
This also changes the expected screen size values of the no-outputs
test; as this case is actually handled now.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
Replace the 'scale' of an output with a vfunc on the MetaMonitorManager
class that takes a monitor and a monitor mode which calculates the
scale. On X11 this always returns 1, on KMS, the old formula is used.
On the dummy and test backends, the already configured values are
returned.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
A MetaOutput is a connector, not exactly a monitor or a region on the
stage; for example tiled monitors are split up into multiple outputs,
and for what is used in input settings, that makes no sense. Change
this to use logical monitors instead of outputs.
https://bugzilla.gnome.org/show_bug.cgi?id=779745
When no output was specified, the screen limit was used to calculate the
aspect ratio. The screen limit, however, is either just an arbitrary
number if no screen limit is applicable, or a hardware graphics buffer
limit, which has nothing to do with anything actually displayed. Change
it to use the screen size instead, to get something that makes more
sense when no output is found.
https://bugzilla.gnome.org/show_bug.cgi?id=779745
Expose via a new API whether the transform on a logical monitor is
handled by the backend. This was previously only exposed only in the
native backend. This will be used to emulate not supporting transforms
in the backend in the nested backend.
https://bugzilla.gnome.org/show_bug.cgi?id=779745
Implement MetaDnd for emitting DnD signals to plugins such as gnome-shell. The
xdnd handling code comes from gnome-shell, and it is hidden behind MetaDnd now.
https://bugzilla.gnome.org/show_bug.cgi?id=765003
When running nested, the pointer can be outside of the stage, meaning
outside of any logical monitor. Handle this when getting the current
logical monitor by falling back to the first logical monitor when the
pointer coordinate is outside of any logical monitor.
https://bugzilla.gnome.org/show_bug.cgi?id=779001
Set up things so that if the INTEL_swap_event extension is not present,
but the driver is known to have good thread support, we use an extra
thread and call glXWaitVideoSync() in the thread. This allows idles
to work properly, even when Mutter is constantly redrawing new frames;
otherwise, without INTEL_swap_event, we'll just block in glXSwapBuffers().
https://bugzilla.gnome.org/show_bug.cgi?id=779039
Split up the X11 backend into two parts, one for running as a
Compositing Manager, and one for running as a nested Wayland
compositor.
This commit also cleans up the compositor configuration calculation,
attempting to make it more approachable.
https://bugzilla.gnome.org/show_bug.cgi?id=777800
The new monitor configuration system (MetaMonitorConfigManager) aims to
replace the current MetaMonitorConfig. The main difference between the
two is that MetaMonitorConfigManager works with higher level input
(MetaMonitor, MetaMonitorMode) instead of directly looking at the CRTC
and connector state. It still produces CRTC and connector configuration
later applied by the respective backends.
Other difference the new system aims to introduce is that the
configuration system doesn't manipulate the monitor manager state; that
responsibility is left for the monitor manager to handle (it only
manages configuration and creates CRTC/connector assignments, it
doesn't apply anything).
The new configuration system allows backends to not rely on deriving the
current configuration from the CRTC/connector state, as this may no longer be
possible (i.e. when using KMS and multiple framebuffers).
The MetaMonitorConfigManager system is so far disabled by default, as
it does not yet have all the features of the old system, but eventually
it will replace MetaMonitorConfig which will at that point be removed.
This will make it possible to remove old hacks introduced due to
limitations in the old system.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
The function meta_monitor_manager_read_current_config() was renamed to
meta_monitor_manager_read_current_state() as it does not read any
configuration, but reads the current state as described by the backend.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
Don't deal with adding/removing tiled Xrandr monitors in the generic
backend, but leave it to the Xrandr backend. The tiled monitor will
itself notify the backend when such a monitor is added and removed.
Tiled Xrandr monitors are now based no MetaMonitor instead of
MetaLogicalMonitor. This means that mirrored tiled monitors will now be
represented correctly.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
The MetaMonitorMode referred to the mode of a CRTC, and with the future
introduction of a MetaMonitor, theh old name would be confusing.
Instead call it what it is.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
The method used for getting the current logical monitor (the monitor
where the pointer cursor is currently at) depends on the backend type,
so move that logic to the corresponding backends.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
In preparation for further refactorizations, rename the MetaMonitorInfo
struct to MetaLogicalMonitor. Eventually, part of MetaLogicalMonitor
will be split into a MetaMonitor type.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
Enabling edge scrolling before disabling two finger would result in
edge scrolling not actually being enabled because two finger is still
enabled at the time and we bail out.
This patch moves this logic to common code for both the native and X
backends and fixes it by ensuring that both settings are never set at
the same time and still re-checking if edge scrolling should be
enabled after two finger scrolling gets disabled.
We also simplify the code by not checking for supported/available
settings since the underlying devices will just reject those values
and there isn't anything we can do about it here. It's the UI's job to
only show supported/available settings to users.
https://bugzilla.gnome.org/show_bug.cgi?id=771744
Allocate the offscreen stage view framebuffers up front; otherwise they
may get allocated after the viewport calculated by the stage is set,
which would cause the viewport to be incorrect until recalculated.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
Support changing the mouse and trackball acceleration profile. This
makes it possible to for example disable pointer acceleration by
choosing the 'flat' profile.
This adds an optional dependency on gudev. Gudev is used by the X11
backend to detect whether a device is a mouse or not. Without gudev
support, the accel profile settings has have effect for mouse devices.
Trackball still uses the "strstr" approach, since udev doesn't support
tagging devices as trackball devices yet.
https://bugzilla.gnome.org/show_bug.cgi?id=769179
Add support for setting edge-scrolling separately from two-finger
scrolling. We now have 2 separate boolean settings for those, with the
Mouse panel in gnome-control-center allowing to set only one of those at
a time, but nothing precludes both being set in the configuration.
We need to handle:
- two-finger-scrolling-enabled and edge-scrolling-enabled settings both
being set.
- those 2 settings being change out-of-order
- two-finger-scrolling being set on a device that doesn't support it
- edge-scrolling-enabled on a device that doesn't support it
And the combinations of one touchpad supporting just one of edge
scrolling and two-finger scrolling and another vice-versa.
https://bugzilla.gnome.org/show_bug.cgi?id=768245
They are already effectively interchangeable so this should reduce
pointless casts.
Just like in GDK though, we need to keep the old definition for
instrospection to be able to include the struct's fields.
Add support for drawing a stage using multiple framebuffers each making
up one part of the stage. This works by the stage backend
(ClutterStageWindow) providing a list of views which will be for
splitting up the stage in different regions.
A view layout, for now, is a set of rectangles. The stage window (i.e.
stage "backend" will use this information when drawing a frame, using
one framebuffer for each view. The scene graph is adapted to explictly
take a view when painting the stage. It will use this view, its
assigned framebuffer and layout to offset and clip the drawing
accordingly.
This effectively removes any notion of "stage framebuffer", since each
stage now may consist of multiple framebuffers. Therefore, API
involving this has been deprecated and made no-ops; namely
clutter_stage_ensure_context(). Callers are now assumed to either
always use a framebuffer reference explicitly, or push/pop the
framebuffer of a given view where the code has not yet changed to use
the explicit-buffer-using cogl API.
Currently only the nested X11 backend supports this mode fully, and the
per view framebuffers are all offscreen. Upon frame completion, it'll
blit each view's framebuffer onto the onscreen framebuffer before
swapping.
Other backends (X11 CM and native/KMS) are adapted to manage a
full-stage view. The X11 CM backend will continue to use this method,
while the native/KMS backend will be adopted to use multiple view
drawing.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
Split the stage window implementations into three separate objects: one
for X11 as a compositing manager, one for X11 running as a nested
Wayland compositor, and one for running with the native backend.
The new stage window implementations are only thin shells; this is in
preparation for making the stage windows behave more differently.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
The stage resizing was placed in the generic backend, which was only
run on certain configurations (when running nested or using the native
backend). This commits makes the resizing more explicit thus more
obvious.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
Instead of passing around the KMS file descriptor via clutter to cogl,
just make our own clutter backend create the cogl renderer and set the
KSM fd.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
MetaRenderer is meant to be the object responsible for rendering the
scene graph. It will contain the logic related to the cogl winsys
backend, the clutter backend, and the clutter stage window.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
Introduce two new clutter backends: MetaClutterBackendX11 and
MetaClutterBackendNative. They are so far only wrap ClutterBackendX11
and ClutterBackendEglNative respectively, but the aim is to move things
from the original clutter backends when needed.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
Emit a signal so that interested parties can recreate their FBOs and
queue a full scene graph redraw to ensure we don't end up showing
graphical artifacts.
This relies on the GL driver supporting the
NV_robustness_video_memory_purge extension and cogl creating a
suitable GL context. For now we only make use of it with the X backend
since the only driver with which this is useful is NVIDIA.
https://bugzilla.gnome.org/show_bug.cgi?id=739178
In order to reuse some vector math for pointer confinement, move out
those parts to its own file, introducing the types old types
"MetaVector2" and "MetaLine2" outside of meta-barrier-native.c, as well
as introducing MetaBorder which is a line, with a blocking direction.
https://bugzilla.gnome.org/show_bug.cgi?id=744104
Right now the XSync based idle monitoring code, will fetch all active
watches into a list, and then call their watch callbacks one by one
as necessary. If one watch callback invalidates another watch, the
list will contain free'd memory.
This commit makes sure to consult the hash table after ever call
of a watch callback, to ensure mutter never looks at freed memory.
Fixes crash reported on IRC by Laine Stump with his synergy setup.
https://bugzilla.gnome.org/show_bug.cgi?id=760330
When the touchpad is two-finger scrolling capable, always enable it.
When the touchpad only supports edge scrolling (usually older devices, and
usually smaller devices), allow disabling the edge scrolling.
This requires a newer gsettings-desktop-schemas as the scroll-method key
was removed, and the edge-scroll-enabled key added.
https://bugzilla.gnome.org/show_bug.cgi?id=759304
Ubuntu ships a patch in the X server that makes the group switch
keybindings only work on key release, i.e. the X server internal group
locking happens on key release which means that mutter gets the
XKB_KEY_ISO_Next_Group key press event, does its XLockGroup() call
with a new index and then, on key release, the X server moves the
index further again.
We can work around this without affecting our behavior in unpatched X
servers by doing a XLockGroup() every time we're notified of the
locked group changing if it doesn't match what we requested.
https://bugzilla.gnome.org/show_bug.cgi?id=756543
We might get modes in XRROutputInfos that aren't in the
XRRScreenResources we get earlier. This always seems to be transient,
i.e. when it happens, the X server will usually send us a follow up
RRScreenChangeNotify where we then get a "stable" view of the world
again.
In any case, when these glitches happen, we end up with NULL pointers
in the MetaOutput->modes array which makes us crash later on. This
patch ensures that doesn't happen.
https://bugzilla.gnome.org/show_bug.cgi?id=756660
This commits refactors cursor handling code and plugs in logic so that
cursor sprites changes appearance as it moves across the screen.
Renderers are adapted to handle the necessary functionality.
The logic for changing the cursor sprite appearance is done outside of
MetaCursorSprite, and actually where depends on what type of cursor it
is. In mutter we now have two types of cursors that may have their
appearance changed:
- Themed cursors (aka root cursors)
- wl_surface cursors
Themed cursors are created by MetaScreen and when created, when
applicable(*), it will extend the cursor via connecting to a signal
which is emitted everytime the cursor is moved. The signal handler will
calculate the expected scale given the monitor it is on and reload the
theme in a correct size when needed.
wl_surface cursors are created when a wl_surface is assigned the
"cursor" role, i.e. when a client calls wl_pointer.set_cursor. A
cursor role object is created which is connected to the cursor object
by the position signal, and will set a correct texture scale given what
monitor the cursor is on and what scale the wl_surface's active buffer
is in. It will also push new buffers to the same to the cursor object
when new ones are committed to the surface.
This commit also makes texture loading lazy, since the renderer doesn't
calculate a rectangle when the cursor position changes.
The native backend is refactored to be triple-buffered; see the comment
in meta-cursor-renderer-native.c for further explanations.
* when we are running as a Wayland compositor
https://bugzilla.gnome.org/show_bug.cgi?id=744932
Use a specialized cursor renderer when running as a nested Wayand
compositor. This new renderer sets an empty X11 cursor and draws the
cursor as part of the stage using the generic cursor renderer drawing
path.
https://bugzilla.gnome.org/show_bug.cgi?id=744932
This fixes build error caused by commit 614d6bd. We can simply remove
the usage of meta-wayland.c functions in non-wayland build because
META_BACKEND_X11_MODE_NESTED is only used in wayland.
https://bugzilla.gnome.org/show_bug.cgi?id=753948
If the user Alt-Tabs out of the window, we will be left thinking
the Alt key is still pressed since we don't see a release for it.
Solve this and other related issues for the nested X11 compositor
by selecting for KeymapStateMask which causes a KeymapNotify event
to be sent after each FocusIn, and when we get these events, update
the internal XKB state and send any necessary modifiers events to
clients.
https://bugzilla.gnome.org/show_bug.cgi?id=753948
Since mutter has two X connections and does damage handling on the
frontend while fence triggering is done on the backend, we have a race
between XDamageSubtract() and XSyncFenceTrigger() causing missed
redraws in the GL_EXT_X11_sync_object path.
If the fence trigger gets processed first by the server, any client
drawing that happens between that and the damage subtract being
processed and is completely contained in the last damage event box
that mutter got, won't be included in the current frame nor will it
cause a new damage event.
A simple fix for this would be XSync()ing on the frontend connection
after doing all the damage subtracts but that would add a round trip
on every frame again which defeats the asynchronous design of X
fences.
Instead, if we move fence handling to the frontend we automatically
get the right ordering between damage subtracts and fence triggers.
https://bugzilla.gnome.org/show_bug.cgi?id=728464
While we shouldn't normally receive crossing events for any windows
except the stage when running nested, we do in case we hold a pointer
grab - just ignore those events instead of taking down the user's
session.
If GL advertises this extension we'll use it to synchronize X with GL
rendering instead of relying on the XSync() behavior with open source
drivers.
Some driver bugs were uncovered while working on this so if we have
had to reboot the ring a few times, something is probably wrong and
we're likely to just make things worse by continuing to try. Let's
err on the side of caution, disable ourselves and fallback to the
XSync() path in the compositor.
https://bugzilla.gnome.org/show_bug.cgi?id=728464
Before submitting a new scroll mode, click method or sendevents mode check if
the value is supported by the device. This avoids BadValue errors when setting
two-finger scrolling on single-finger touchpad devices since we can't easily
handle BadValue (see 9747277b)
https://bugzilla.gnome.org/show_bug.cgi?id=750816
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
We should not be setting random output properties like this.
Use the function we just introduced to only set the underscan flag when
it's actually supported.
So that clients such as the control center can decide to hide an
underscanning checkbutton when the output does not support it.
Support in the KMS / native backend to come later...
It seems that fglrx sometimes gives us absolute junk when requesting the
outputs, and if we don't trap errors, we'll just crash when trying to
configure a junk output. Use xcb so errors simply get ignored.
For enter / leave events, which we use in the UI code, we need to make
sure that these coordinates are root-relative as well, otherwise the
cursor when entering frames might be incorrect.
If we're running as a nested compositor, we must not attempt to
passive grab on the root window, and we should be setting the
touch event mask on the stage window.
https://bugzilla.gnome.org/show_bug.cgi?id=751036
This way, we won't be hit with BadValue errors if we set it to a value
outside the X device's range. This can happen for touchpads without
two-finger scrolling, for instance.
this just adds backend support for retrieving the tile
information from X11 (randr 1.5) and native backends.
It stores the tiling information into the output struct.
We'll need to get the value of some properties. Fail if the number of
items returned is less than we expect and warn if it exceeds it so
that we can easily find out if items are added to a property later and
fix it.
Some DRM drivers have added a consistent set of properties that
allow compensating for the overscan that some TVs do, without the
user being able to disable.
There is copy&pasted code in set_scroll_button, which is apparently
wrong, because it is trying to set scroll method instead of the scroll
button...
https://bugzilla.gnome.org/show_bug.cgi?id=747967
On X11, calling this function on meta_display_handle_events() will not catch
mouse events happening over clients, so poke directly in the backend for
XI_DeviceChanged events, which mutter will get on device switches.
The code has been slightly refactored so we deal with XIEvents at a single
handle_input_event() function.
https://bugzilla.gnome.org/show_bug.cgi?id=712775
This just exposes the type and the singleton getter necessary to make
it available to introspection. We'll expose more functionality as it
becomes needed.
https://bugzilla.gnome.org/show_bug.cgi?id=743745
This goes through modifying XI2 device properties, either common ones (eg.
set on every device) or those specific to the libinput X11 driver. Keyboard
repeat/rate are set through core and XKB APIs.
https://bugzilla.gnome.org/show_bug.cgi?id=739397
This patch removes the X11 specific code from MetaBarrier and creates an
abstraction layer MetaBarrierImpl. The existing X11 implementation is
moved to a new GObject MetaBarrierImplX11 implementing the abstract
interface MetaBarrierImpl which is instantiated by MetaBarrier when
supported.
While at it, move it to backends/ and properly name the files.
https://bugzilla.gnome.org/show_bug.cgi?id=706655
EDID parsing has been refactored to a common meta_output_parse_edid()
function, which ensures the extracted information is the same on both KMS
and X11 backend, so it can be used consistently on eg. settings values.
https://bugzilla.gnome.org/show_bug.cgi?id=742882
This reverts commit 47e339b46e. The
approach that was used to reduce the amount of work we do on RR events
to the necessary minimum is flawed. It assumes that, when the first
event we see where the retrieved XRRScreenResources.timestamp is
bigger than the previous, we already have all the data we need to
rebuild our view of the world.
That isn't true however, because the X server sends
RRScreenChangeNotify events for every step of the configuration
change, i.e. it lacks an atomic reconfiguration API. In particular, if
the X screen size is one of the changes, when we rebuild our state and
emit monitors-changed, the X screen size might still be the previous
one and since we stop updating ourselves until another reconfiguration
happens (noticed by looking at XRRScreenResources.timestamp) we end up
with the wrong idea of the X screen size.
https://bugzilla.gnome.org/show_bug.cgi?id=738630
This optimization breaks our use of XRRScreenResources' timestamps to
detect hotplugs in case one of the outputs is disconnected and the
remaining ones don't need any mode, position or transform adjustments.
In that scenario, when applying the new configuration, we resize the X
screen but never call XRRSetCrtcConfig() and since XRRSetScreenSize()
doesn't take a timestamp and the X server doesn't update its last set
timestamp, when we next get a RRScreenChangeNotify and update
ourselves, XRRScreenResources.timestamp will still be smaller than
XRRScreenResources.configTimestamp which makes us think we're seeing a
new hotplug. We just don't enter an endless loop because the screen
size that we keep applying is always the same and the X server
short-circuits and stops sending us RRScreenChangeNotifys.
Always calling XRRSetCrtcConfig() ensures that the last set timestamp
will be bigger than configTimestamp in the next event and thus making
us trigger the monitors-changed signal properly.
Note that the X server already does basically the same checks that
we're removing here, so doing this shouldn't be a significant
efficiency loss. See
http://cgit.freedesktop.org/xorg/xserver/tree/randr/rrcrtc.c?h=server-1.16-branch#n539
In recent versions of the QXL driver, it may set "suggested X|Y" connector
properties. These properties are used to indicate the position at which
multiple displays should be aligned. If all outputs have a suggested position,
the displays are arranged according to these positions, otherwise we fall back
to the default configuration.
At the moment, we trust that the driver has chosen sane values for the
suggested position.
The X server sends several RRScreenChangeNotify events in a burst when
something happens which, currently, causes us to rebuild our view of
the world as many times and notify the upper layers about it which
causes a lot of bogus repeated work like rebuilding background actors.
We can avoid this extra work by looking at the timestamp in the
XRRScreenResources struct which is updated when an X client (including
us!) last changed something and comparing it with the previous
timestamp.
https://bugzilla.gnome.org/show_bug.cgi?id=738630
meta_monitor_config_match_current() only matches the number of outputs
and if the output connector, vendor, product and serial match.
In the X backend, this means that we can't use it to bypass doing any
work because it won't detect cases where we actually want to update
ourselves like e.g. an output being turned off either by us or by
another X client (e.g. xrandr).
In the native backend, unlike the xrandr backend, we only get called
on real hotplug events and thus should always trigger the common
hotplug code to (possibly) apply a new mode so the check is pointless
anyway.
https://bugzilla.gnome.org/show_bug.cgi?id=738630
In randr events, configTimestamp can be considered the hotplug time,
i.e. whenever the server notices hardware changes, this value will be
updated.
Having that in mind, we can re-work the logic to make it clearer.
There are no semantic changes.
The code here was a bit messy with the addition of
hotplug_mode_update, and the comments were a bit confusing and
inaccurate. Clean it up and comment it a bit better to make the flow and
intention more clear.
The X server applies a default keymap to hotplugged keyboard
devices. To enforce our current settings we must re-upload the keymap
when a new keyboard shows up.
Note that setting the VCK keymap causes the server to propagate it
to all slave keyboard devices.
https://bugzilla.gnome.org/show_bug.cgi?id=737673
In the case of a nested Wayland compositor inside an X session,
Clutter is managing the toplevel window size, so don't call
XResizeWindow on it - this will confuse Clutter and get the size
and the hints out of sync on the toplevel window.
https://bugzilla.gnome.org/show_bug.cgi?id=736279
RandR's QueryOutputProperty request makes the incredible decision of
throwing a BadName if you pass a property that doesn't exist, which
means that trying to check if a property exists is a royal pain when
using Xlib.
XCB's interface is much more friendly about errors and not having global
state and things like that, so use that instead to query our backlight
property.
If the property doesn't exist, a BadName error will be generated. This
is a terrible API, but it's what we're stuck with. Use
RRGetOutputProperty instead.
meta_backend_get_keymap is supposed to return a static keymap, not a new
one every time. Cache it internally. We don't update it when the keymap
changes on the server, but we'll do this soon.
This allows creating the stage much earlier than it otherwise would have
been. Our initialization sequence has always been a bit haphazard, with
first the MetaBackend created, then the MetaDisplay, and inside of that,
the MetaScreen and MetaCompositor.
Refactor this out so that the MetaBackend creates the Clutter
stage. Besides the clarity of early initialization, we now have much
easier access to the stage, allowing us to use it for things such as
key focus and beyond.
These methods allow us to set and get xkbcommon keymaps as well as
locking a specific layout in a layout group.
With this, we introduce dependencies on xkeyboard-config, xkbfile,
xkbcommon-x11 and a libX11 new enough to have xcb support.
https://bugzilla.gnome.org/show_bug.cgi?id=734301
Sometimes we can get a host event without having the display up and
running yet. Just don't pass it to the compositor in that case, since it
won't be possible for it to have any event that matters.
This reverts commit 3b85e4b2b9.
This breaks touch support; reverting would break wayland
(is what this patch tried to fix; we should find a better solution
that works on both).
When a touch sequence is passively grabbed and later rejected, events
will be replayed on the next client in propagation order, although those
events (either transformed to pointer events or not) will contain the
original timestamps, this will make grabs fail with InvalidTime if triggered
from the replayed ButtonPress/TouchBegin handler.
In order to work around this, store the most recent event time (presumably
gotten from the XI_TouchEnd caused by the passive grab being rejected), and
use that time on the events being replayed afterwards and grabs, so we don't
possibly fail with InvalidTime if those events result in a compositor grab.
The output_id is more of an opaque identifier for the monitor, based on
its underlying ID from the windowing system. Since we also use the term
"output_id" for the output's index, rename our use of the opaque cookie
"output_id" to "winsys_id".
This makes Alt+F7 / Alt+F8 work respectively under X11 nested mode.
For the native backend implementation, we'll need a special Clutter
function, so don't implement that for now.
When we click on a window with a passive grab, then the event_x
and event_y will be relative to that window, instead of relative to
the stage, which means that picking will be wrong.
Forcibly using root_x / root_y breaks nested mode. Nested mode is
a testing mode that should be replaced by a DRI3-enabled Xephyr,
though. It's getting too hairy to support properly.
