The property is deprecated and the current implementation simply
redirects it to ClutterActor::background-color, so remove it.
Also update the tests to set the background color directly.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1332
It is deprecated in favor of the 'z-position' property, and
the implementation itself redirects to the z-position, so
just drop it and replace all get|set_depth calls to their
z-position counterparts.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1332
We were setting the pipeline colour to all white (1.0, 1.0, 1.0, 1.0)
and so the default layer combine function multiplied each pixel
(R, G, B, A) by all ones. Obviously multiplying by one four times per
pixel is a waste of effort so we remove the colour setting *and* set
the layer combine function to a trivial shader that will ignore whatever
the current pipeline colour is set to. So now we do **zero** multiplies
per pixel.
On an i7-7700 at UHD 3840x2160 this results in 5% faster render times
and 10% lower power usage (says intel_gpu_top). The benefit is probably
much higher for virtual machines though, as they're no longer being
asked to do CPU-based math on every pixel of a window.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1331
The previous commit removed checks for intermediate focus states which
would make tests randomly fail, because of their time dependence. What
can be tested however is that if there is no other window available that
would accept the focus, that the focus remains at 'none', after the
focused window has been closed. This newly introduced test checks the
focus directly after closing the window (and syncing) and after the time
it would have taken for the queue to finish. The first check has a
similar timing issue as the removed focus checks in the other tests, but
the test will never accidentally fail, because regardless of whether the
queue has finished or not, the focus is always expected to be 'none'.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1329
While c3d13203 ensured that the test-client has actually closed the
window before testing for the focus change, it also made another timing
related issue with the tests more likely to happen. Serveral tests
assert that the focus is set to 'none' after the focussed window has
been closed when the window below does not accept focus. This however
can never be reliably tested, because closing the window triggers
timeout based iteration of a queue of default focus candidate windows.
This starts after the window has been closed and might finish before the
clients have finished synchronizing. This issue is more likely to
trigger the shorter the queue is and the more test clients there are
that could delay the synchronization.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1329
This avoids some issues which could happen on some setups[0] due to
meta-native-renderer.c:dummy_power_save_page_flip →
meta_onscreen_native_swap_drm_fb implicitly turning of the primary
plane (by destroying the KMS framebuffer assigned to it):
* drmModeObjectSetProperty could return an "Invalid argument" error
between setting a non-empty cursor with drmModeSetCursor(2) and
enabling the primary plane again:
Failed to DPMS: Failed to set connector 69 property 2: Invalid argument
(This was harmless other than the error message, as we always re-set
a mode on the CRTC after setting the DPMS property to on, which
enables the primary plane and implicitly sets the DRM property to on)
* drmModeSetCursor(2) could return an "Invalid argument" error between
setting the DPMS property to on and enabling the primary plane again:
Failed to set hardware cursor (drmModeSetCursor failed: Invalid argument), using OpenGL from now on
[0] E.g. with the amdgpu DC display code.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1240
In commit 4c1fde9d MetaCullable related code was moved out of
MetaShapedTexture into MetaSurfaceActor. While generally desirable,
this removed drawing optimizations in MetaShapedTexture for partial
redraws. The common case for fully obscured actors was still supposed
to work, but it was now discovered that it actually did not.
This commit revert parts of 4c1fde9d: it reintroduces clipping
to MetaShapedTexture but leaves all culling and actor related logic
in MetaSurfaceActor.
Thanks to Daniel van Vugt for uncovering the issue.
Fixes https://gitlab.gnome.org/GNOME/mutter/-/issues/850
Fixes https://gitlab.gnome.org/GNOME/mutter/-/issues/1295https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1326
When trying to find a default focus window, the code iterates through a
queue of candidates with a timeout between each candidate. If the window
the current timeout is waiting for gets destroyed, this process just
stops instead of trying the next window in the queue.
This issue was made more likely to be triggered with the previous change
to the closed-transient-no-input-parents-queued-default-focus-destroyed
test due to the introduction of a wait, which can introduce a
delay between the two destroy commands.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1325
Some tests were not waiting for the test client to actually issue
destroy commands before checking their effect on the window focus.
Similarly when mutter is supposed to change the focus based on a delay
by sending a WM_TAKE_FOCUS to the client, this also could fail without
synchronization with the client before checking the result.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1325
We delegate the answer through CoglDriverVtable::is_hardware_accelerated
since this is properly a property of the renderer, and not something the
cogl core should know about. The answer given for the nop driver is
admittedly arbitrary, yes it's infinitely fast but no there's not any
"hardware" making it so.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1194
Event delivery with grabbing popups stay essentially the same within
the grabbing client, we still must honor the implicit grab as long as
there is one.
This is however not the case, the popup_grab_focus() function ignores
the button state. The popup_grab_button() function will already indirectly
re-sync the focus surface after the last button is released, so checking
for button state in popup_grab_focus() is sufficient to make the implicit
grab honored with popup grabs involved.
Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1275https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1270
When a touch sequence was rejected, we'd update the event timestamps of
incoming touch events to help with implementing grabs. This was done by
sending a ClientMessage with a counter, and comparing the counter to
decide whether we're seing a replayed event or not.
This had the unforseen consequence that we would potentially end up
destroying all actors including the stage, since, when mutter receives a
ClientMessage event, it would assume that it's a WM_PROTOCOLS event, and
handle it as such. The problem with this approach is that it would
ignore fact that there might be other ClientMessage types sent to it,
for example the touch synchronization one. What could happen is that the
touch count value would match up with the value of the WM_DELETE_WINDOW
atom, clutter would treat this as WM_PROTOCOLS:WM_DELETE_WINDOW, which
it'd translate to clutter_actor_destroy(stage).
Destroying the stage in such a way is not expected, and caused wierd
crashes in different places depending on what was going on.
This commit make sure we only treat WM_PROTOCOLS client messages as
WM_PROTOCOLS client messages effectively avoiding the issue.
This fixes crashes such as:
#0 meta_window_get_buffer_rect (window=0x0, rect=rect@entry=0x7ffd7fc62e40) at core/window.c:4396
#1 0x00007f1e2634837f in get_top_visible_window_actor (compositor=0x297d700, compositor=0x297d700) at compositor/compositor.c:1059
#2 meta_compositor_sync_stack (compositor=0x297d700, stack=<optimized out>, stack@entry=0x26e3140) at compositor/compositor.c:1176
#3 0x00007f1e263757ac in meta_stack_tracker_sync_stack (tracker=0x297dbc0) at core/stack-tracker.c:871
#4 0x00007f1e26375899 in stack_tracker_sync_stack_later (data=<optimized out>) at core/stack-tracker.c:881
#5 0x00007f1e26376914 in run_repaint_laters (laters_list=0x7f1e2663b7d8 <laters+24>) at core/util.c:809
#6 run_all_repaint_laters (data=<optimized out>) at core/util.c:826
#7 0x00007f1e26b18325 in _clutter_run_repaint_functions (flags=flags@entry=CLUTTER_REPAINT_FLAGS_PRE_PAINT) at clutter-main.c:3448
#8 0x00007f1e26b18fc5 in master_clock_update_stages (master_clock=0x32d6a80, stages=0x4e5a740) at clutter-master-clock-default.c:437
#9 clutter_clock_dispatch (source=<optimized out>, callback=<optimized out>, user_data=<optimized out>) at clutter-master-clock-default.c:567
#10 0x00007f1e27e48049 in g_main_dispatch (context=0x225b8d0) at gmain.c:3175
#11 g_main_context_dispatch (context=context@entry=0x225b8d0) at gmain.c:3828
#12 0x00007f1e27e483a8 in g_main_context_iterate (context=0x225b8d0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at gmain.c:3901
#13 0x00007f1e27e4867a in g_main_loop_run (loop=0x24e29f0) at gmain.c:4097
#14 0x00007f1e2636a3dc in meta_run () at core/main.c:666
#15 0x000000000040219c in main (argc=1, argv=0x7ffd7fc63238) at ../src/main.c:534
and
#0 0x00007f93943c1f25 in raise () at /usr/lib/libc.so.6
#1 0x00007f93943ab897 in abort () at /usr/lib/libc.so.6
#2 0x00007f9393e1e062 in g_assertion_message (domain=<optimized out>, file=<optimized out>, line=<optimized out>, func=0x7f93933e6860 <__func__.116322> "meta_x11_get_stage_window",
#3 0x00007f9393e4ab1d in g_assertion_message_expr ()
#4 0x00007f939338ecd7 in meta_x11_get_stage_window (stage=<optimized out>) at ../mutter/src/backends/x11/meta-stage-x11.c:923
#5 0x00007f939339e599 in meta_backend_x11_cm_translate_device_event (x11=<optimized out>, device_event=0x55bc8bcfd6b0) at ../mutter/src/backends/x11/cm/meta-backend-x11-cm.c:381
#6 0x00007f939339f2e2 in meta_backend_x11_translate_device_event (device_event=0x55bc8bcfd6b0, x11=0x55bc89dd5220) at ../mutter/src/backends/x11/meta-backend-x11.c:179
#7 0x00007f939339f2e2 in translate_device_event (device_event=0x55bc8bcfd6b0, x11=0x55bc89dd5220) at ../mutter/src/backends/x11/meta-backend-x11.c:208
#8 0x00007f939339f2e2 in maybe_spoof_event_as_stage_event (input_event=0x55bc8bcfd6b0, x11=0x55bc89dd5220) at ../mutter/src/backends/x11/meta-backend-x11.c:284
#9 0x00007f939339f2e2 in handle_input_event (event=0x7fff62d60490, x11=0x55bc89dd5220) at ../mutter/src/backends/x11/meta-backend-x11.c:309
#10 0x00007f939339f2e2 in handle_host_xevent (event=0x7fff62d60490, backend=0x55bc89dd5220) at ../mutter/src/backends/x11/meta-backend-x11.c:413
#11 0x00007f939339f2e2 in x_event_source_dispatch (source=<optimized out>, callback=<optimized out>, user_data=<optimized out>) at ../mutter/src/backends/x11/meta-backend-x11.c:467
#12 0x00007f9393e6c39e in g_main_dispatch (context=0x55bc89dd03e0) at ../glib/glib/gmain.c:3179
#13 0x00007f9393e6c39e in g_main_context_dispatch (context=context@entry=0x55bc89dd03e0) at ../glib/glib/gmain.c:3844
#14 0x00007f9393e6e1b1 in g_main_context_iterate (context=0x55bc89dd03e0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/glib/gmain.c:3917
#15 0x00007f9393e6f0c3 in g_main_loop_run (loop=0x55bc8a042640) at ../glib/glib/gmain.c:4111
#16 0x00007f9393369a0c in meta_run () at ../mutter/src/core/main.c:676
#17 0x000055bc880f2426 in main (argc=<optimized out>, argv=<optimized out>) at ../gnome-shell/src/main.c:552
Related: https://gitlab.gnome.org/GNOME/mutter/-/issues/338
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/951https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1317
Make the clutter_input_device_get_actor() API public and remove
clutter_input_device_get_pointer_actor() in favour of the new function.
This allows also getting the "pointer" actor for a given touch sequence,
not only for real pointer input devices like mice.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1275
Add a method to ClutterSeat that allows peeking the list of input
devices and allow looping through devices a bit faster. The API left is
private so we can make use of peeking the GList internally, but don't
have to expose any details to the outside, which means we'd have to
eventually stick with a GList forever to avoid breaking API.
Since we now have the peek_devices() API internally, we can implement
ClutterSeats public list_devices() API using g_list_copy() on the list
returned by peek_devices().
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1275
As explained in the last commits, we'll let gnome-shell take care of
this since freezing and thawing needs to be decoupled from the effect
starting and ending.
So stop freezing the MetaWindowActor when starting the effect and
thawing the actor when ending the effect.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1250
As explained in the last commit, gnome-shell needs to be able to thaw
window actor updates during its size-change effect is active.
So make meta_window_actor_freeze() and meta_window_actor_thaw() public
API, which will allow the shell to freeze and thaw actor updates itself.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1250
The size-change animation in gnome-shell needs to sync the window actors
geometry during the animation, it currently does this by notifying the
compositor that the animation was finished before it actually is.
This causes a few bugs in Mutter though, since it will now emit the
"effects-completed" signal on the window actor even though they aren't
completed.
To fix that, we need to decouple freezing and thawing of actor updates
from window effects and allow gnome-shell to thaw actor updates before
it notifies Mutter that the effect is completed.
The first step for this is allowing to sync the actor geometry while an
effect is active, this should be redundant since effects which actually
need to inhibit those updates will freeze the actor anyway. Also a
geometry change happening while another effect is active will kill the
old effect anyway because MetaPluginManager kills all the active window
effects before starting a new one; so the new size-change effect for any
geometry change is going to kill the current effect.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1250
Trying to figure out what this comment was actually about, it turns out
that MSC means Media Stream Counter, and as mentioned in an article[0]
is related to DRI3 and the X11 Present extension. Anyway, the comment
has been there raising questions for some years now, I think we can
remove it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
The ID and name are just moved into the instance private, while the rest
is moved to a `MetaCrtcModeInfo` struct which is used during
construction and retrieved via a getter. Opens up the possibility to
add actual sub types.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
Just as with MetaOutput, instead of the home baked "inheritance" system,
using a gpointer and a GDestroyNotify function to keep the what
effectively is sub type details, make MetaCrtc an abstract derivable
type, and make the implementations inherit it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
Instead of the home baked "inheritance" system, using a gpointer and a
GDestroyNotify function to keep the what effectively is sub type
details, make MetaOutput an abstract derivable type, and make the
implementations inherit it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
It's used for two things: avoid reading configs, and actual hotplug
update mode. The former requires the suggested position to be (-1, -1)
to trick the monitor configuration generator to skip using the suggested
position even if hotplug update mode is set to TRUE. The latter should
use the actual hotplug mode coordinates.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
Now set as a property during construction. Only actually set by the
Xrandr backend, as it's the only one currently not supporting all
transforms, which is the default.
While at it, move the 'ALL_TRANFORMS' macro to meta-monitor-tranforms.h.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
The output info is established during construction and will stay the
same for the lifetime of the MetaOutput object. Moving it out of the
main struct enables us to eventually clean up the MetaOutput type
inheritence to use proper GObject types.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
MetaCrtcInfo and MetaOutputInfo did not represent information about
MetaCrtc and MetaOutput, but the result of the monitor configuration
assignment algorithm, thus rename it to MetaCrtcAssignment and
MetaOutputAssignment.
The purpose for this is to be able to introduce a struct that actually
carries information about the CRTCs and outputs, as retrieved from the
backend implementations.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
That is is_presentation, is_primary, is_underscanning and backlight.
The first three are set during CRTC assignment as they are only valid
when active. The other is set separately, as it is untied to
monitor configuration.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
It was used during configuration to ensure that we always dealt with
every output and CRTC. Do this without polluting the MetaOutput and
MetaCrtc structs with intermediate variables not used by the
corresponding types themself.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287
The current code assumes that the actor will always have the same
size and position of the background texture, but part of the implicit
contract of being a ClutterContent is being able to render itself
at any given actor, at any given size.
For example, if the current code is given an actor with 0x0+100+100
as geometry, and no clipped region, it'll render not the whole
background, but the 0x0+100+100 rectangle of the background. In
practice, the actor geometry acts like a "clip mask" over the
background texture, due to the assumption that the actor will
always have the same size of the monitor.
Make the calculation of the texture slices relative to the actor
box.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1302
MetaBackgroundActor is still necessary for culling purposes,
but now the actual rendering of the background is delegated
to MetaBackgroundContent, as well as the sizing information.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1302
MetaBackgroundContent is a ClutterContent implementation
that can render a background to any attached actor. Right
now, it preserves all the properties and the rendering
model of MetaBackgroundActor.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1302
X11 window stacking operations are by nature prone to race conditions.
For example, we might queue a "raise above" operation, but before it
actually takes place, the sibling the window was to be rased above, is
withdrawn.
In these cases we'd log warnings even though they are expected to
happen. Downgrade these warnings to debug messages, only printed when
MUTTER_VERBOSE is set.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1300
Test that the stage-views list of ClutterActor is correct when moving an
actor, reparenting it, or hiding an actor up the hierarchy. Also test
that the "stage-views-changed" signal works as expected.
Don't test actor transforms for now because those aren't supported yet.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1196
When the stage views the stage is shown on are changed, ClutterStage
currently provides a clutter_stage_update_resource_scales() method
that allows invalidating the resource scales of all actors. With the new
stage-views API that's going to be added to ClutterActor, we also need a
method to invalidate the stage-views lists of actors in case the stage
views are rebuilt and fortunately we can re-use the infrastructure for
invalidating resource scales for that.
So since resource scales depend on the stage views an actor is on,
rename clutter_stage_update_resource_scales() and related methods to
clutter_stage_clear_stage_views(), which also covers resource scales.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1196
When an app disappears after some data from it has been copied to the
clipboard, the owner of the clipboard selection becomes a new memory
selection source. The initial reference this new selection source is
never unref'ed, which leads to this being leaked on the next clipboard
selection owner change.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1293
Using XDG_CONFIG_HOME allows users to place their keyboard configuration into
their home directory and have them loaded automatically.
libxkbcommon now defaults to XDG_CONFIG_HOME/xkb/ first, see
https://github.com/xkbcommon/libxkbcommon/pull/117
However - libxkbcommon uses secure_getenv() to obtain XDG_CONFIG_HOME and thus
fails to load this for the mutter context which has cap_sys_nice.
We need to manually add that search path as lookup path.
As we can only append paths to libxkbcommon's context, we need to start with
an empty search path set, add our custom path, then append the default search
paths.
The net effect is nil where a user doesn't have XDG_CONFIG_HOME/xkb/.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/936
We would get the MetaDisplay from the backend singleton before creating
the MetaCompositor, then in MetaCompositor, get the backend singleton
again to get the stage. To get rid of the extra singleton fetching, just
pass the backend the MetaCompositor constructors, and fetch the stage
directly from the backend everytime it's needed.
This also makes it available earlier than before, as we didn't set our
instance private stage pointer until the manage() call.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1289
Also fix a test that dependends on a specific element order in a list
that wasn't defined to have any particular order.
The frames per second is decreased from 30 to 10, to make the test less
flaky when running in CI.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1289
The shadow was disabled for the X11 client as it was far to unreliable
when comparing sizes.
It seems that the Wayland backend has been somewhat unreliable as well,
where some race condition causing incorrect sizes thus a flaky test.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1288
A "show" command calls gtk_window_show() and gdk_display_sync(), then
returns. This means that the X11 window objects are guaranteed to have
been created in the X11 server.
After that, the test runner will look up the window's associated
MetaWindow and wait for it to be shown.
What this doesn't account for is if mutter didn't get enough CPU time to
see the new window. When this happens, the 'default-size' stacking test
sometimes failed after hiding and showing the X11 window.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1288
When we created the DMA buffer backed CoglFramebuffer, we handed it over
to CoglDmaBufHandle which took its own reference. What we failed to do
was to release our own reference to it, effectively leaking it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1283
The stream will clean up the buffers, so let it do that before we
destroy them under its feet. Note that it'll only do this after the
following PipeWire commit:
commit fbaa4ddedd84afdffca16f090dcc4b0db8ccfc29
Author: Wim Taymans <wtaymans@redhat.com>
Date: Mon Jun 1 15:36:09 2020 +0200
stream: allow NULL param and 0 buffers in disconnect
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1283
wait_reconfigure ensures that the whole configure back and forth
completes before continuing. Doing this after every state change ensures
that we always end up with the expected state, thus fixes flakyness of
the restore-position stacking test.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1279
This cannot be made to work reliably. Some factoids:
- Internal devices may be connected via USB.
- The ACPI spec provides the _PLD (Physical location of device) hook to
determine how is an USB device connected, with an anecdotal success
rate. Internal devices may be seen as external and vice-versa, there is
also an "unknown" value that is widely used.
- There may be non-USB keyboards, the old "AT Translated Set 2 Keyboard"
interface does not change on hotplugging.
- Libinput has an internal series of quirks to classify keyboards as
internal of external, also with an "unknown" value.
These heuristics are kinda hopeless to get right by our own hand. Drop
this external keyboard detection in the hope that there will be something
more deterministic to rely on in the future (e.g. the libinput quirks
made available to us directly or indirectly).
Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2378
Related: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2353https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1277
Move Wayland support (i.e. the MetaWaylandCompositor object) made to be
part of the backend. This is due to the fact that it is needed by the
backend initialization, e.g. the Wayland EGLDisplay server support.
The backend is changed to be more involved in Wayland and clutter
initialization, so that the parts needed for clutter initialization
happens before clutter itself initialization happens, and the rest
happens after. This simplifies the setup a bit, as clutter and Wayland
init now happens as part of the backend initialization.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1218
On X11 we don't update the texture in certain circumstances, such as if
the surface is a fullscreen unredirect, or doesn't have a Pixmap. On
Wayland we only want to avoid updating the texture if there is no
texture, but as this is handled implicitly by MetashapedTexture, we
don't need to try to emulate the X11-y conditions in the generic layer
and instead just have the implementations handle update processing
themself.
This doesn't have any functional changes, but removes a vfunc from
MetaSurfaceActorClass.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1218
We failed to use the buffer age when monitors were rotated, as when they
are, we first composite to an offscreen framebuffer, then later again to
the onscreen. The buffer age checking happened on the offscreen, and an
offscreen being single buffered, they can't possible support buffer
ages.
Instead, move the buffer age check to check the actual onscreen
framebuffer. The offscreen to onscreen painting is still always full
frame, but that will be fixed in a later commit.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1237
