Commit Graph

25106 Commits

Author SHA1 Message Date
Thomas Hindoe Paaboel Andersen
bcc519e4ee clutter: return correct enum type
clutter_event_get_scroll_finish_flags() should return a ClutterScrollFinishFlags
but due to what looks like a bad copy/paste it instead returns a
ClutterScrollSource on asserts.

The definitions of the enums are these:

typedef enum
{
  CLUTTER_SCROLL_SOURCE_UNKNOWN,
  CLUTTER_SCROLL_SOURCE_WHEEL,
  CLUTTER_SCROLL_SOURCE_FINGER,
  CLUTTER_SCROLL_SOURCE_CONTINUOUS
} ClutterScrollSource;

typedef enum
{
  CLUTTER_SCROLL_FINISHED_NONE       = 0,
  CLUTTER_SCROLL_FINISHED_HORIZONTAL = 1 << 0,
  CLUTTER_SCROLL_FINISHED_VERTICAL   = 1 << 1
} ClutterScrollFinishFlags;

The asserts would only return CLUTTER_SCROLL_SOURCE_UNKNOWN. This
is equal to CLUTTER_SCROLL_FINISHED_NONE which this patch uses
instead. Thus no functional change is intended. This only fixes a
compile warning.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/931
2019-11-12 17:09:09 +01:00
Georges Basile Stavracas Neto
044238b503 clutter/actor: Draw paint volumes using paint nodes
Clutter has a draw debug mode that allows for painting
paint volumes. Right now, this debug mode uses the old
immediate paint mode.

Switch the painting of paint volumes to use paint nodes,
and sneak a few minor style cleanups.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/890
2019-11-11 10:40:44 -03:00
Georges Basile Stavracas Neto
03b59f9e19 clutter/actor: Move paint flag to ClutterActorNode
Now that we unconditionally use ClutterActorNode to
paint ClutterActors, move the PAINT private flag to
the ClutterActorNode. This way, we can run the paint
on the actor anywhere inside the paint tree.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/890
2019-11-11 10:40:44 -03:00
Jonas Ådahl
7193938d27 compositor: Guard against untimely calls
It seems that sometimes these functions are called by Javascript in
GNOME Shell during tear down. This causes segfaults and crash reports,
but without any backtraces other than the entry and exit points into
gjs.

In order to get more useful information about where these calls come
from, validate the input passed gracefully, by complaining in the log
and returning NULL values.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/926
2019-11-11 13:09:20 +00:00
Hans de Goede
5afec87b96 input-settings/x11: Add missing clutter_x11_trap_x_errors around XIGetProperty
Add missing clutter_x11_[un]trap_x_errors around the XIGetProperty call
in meta-input-settings-x11.c's get_property helper function.

This fixes mutter crashing with the following error if the XInput device
goes away at an unconvenient time:

 X Error of failed request:  XI_BadDevice (invalid Device parameter)
   Major opcode of failed request:  131 (XInputExtension)
   Minor opcode of failed request:  59 ()
   Device id in failed request: 0x200011
   Serial number of failed request:  454
   Current serial number in output stream:  454

https://gitlab.gnome.org/GNOME/mutter/merge_requests/928
2019-11-10 19:45:08 +01:00
Robert Mader
a4f51da184 plugin-manager: Kill window effects on destroy
We do so for all other window effects already. Why this was left out
is unknown (9b3a0d1ad8), but we will need it for a fix in GS.

Related: https://gitlab.gnome.org/GNOME/mutter/issues/655

https://gitlab.gnome.org/GNOME/mutter/merge_requests/924
2019-11-08 22:18:09 +00:00
Florian Müllner
0545b93232 plugins/default: Handle skipped animations
We currently assume that the actor_animate() helper function returns
a timeline. However Clutter may skip implicit animations and simple
set properties directly, for example when the actor is hidden.

The returned timeline will be NULL in that case, and we abort when
using it as instance parameter to g_signal_connect().

Fix this by only setting up a completed handler when we are actually
animating, and complete the effect directly otherwise.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/925
2019-11-08 22:49:31 +01:00
Adam Jackson
9cbf83d59c cogl: glBlendFuncSeparate is always available
So we don't need glBlendFunc.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/903
2019-11-08 12:15:39 +00:00
Adam Jackson
07ca100130 cogl: glBlendEquationSeparate is always available
So we don't need glBlendEquation.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/903
2019-11-08 12:15:39 +00:00
Marco Trevisan (Treviño)
6944839ab6 window-props: Read WM_TRANSIENT_FOR for override-redirect windows
As per the Extended Window Manager Hints standard version 1.3 [1] an
override-redirect window can set a transient-for window per compositing and
app-matching purposes.

So just read the WM_TRASIENT_FOR property also for such windows, adapting
the error in case they are transient for another O-R window and adding a
test to check such case.

[1] https://standards.freedesktop.org/wm-spec/wm-spec-latest.html#idm140200472512128

https://gitlab.gnome.org/GNOME/mutter/merge_requests/920
2019-11-07 18:43:16 +00:00
Xiang Fan
4a76f66a54 wayland/surface: Don't double scale when getting absolute coordinates
The actor is already in surface coordinate space, so we should not scale
with the buffer scale to transform surface coordinates to stage
coordinates.

This bug causes input method using wayland text-input protocol to
receive wrong cursor location. Reproduced in ibus (when candidate
window is open) with scaling factor other than 1.

This commit also fixes pointer confinement.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/915
2019-11-07 16:20:13 +00:00
Marco Trevisan (Treviño)
bacbbbd628 window-props: Don't set override redirect windows as top-level parent
Java applications might use override-redirect windows as parent windows for
top-level windows, although this is not following the standard [1].

In such case, the first non-override-redirect child window that is created
was marked as being on_all_workspaces since the call to
should_be_on_all_workspaces() returns TRUE for its parent, and this even
though the on_all_workspaces_requested bit is unset.
When a further child of this window was added, it was set as not having a
workspace and not being on_all_workspaces, since the call to
should_be_on_all_workspaces() for its parent would return FALSE (unless if
it is in a different monitor, and the multiple-monitors workspaces are
disabled).

Since per commit 09bab98b we don't recompute the workspace if the
on_all_workspaces bit is unset, we could end up in a case where a window can
be nor in all the workspaces or in a specific workspace.

So let's just ignore the transient_for bit for a window if that points to an
override-redirect, using the x11 root window instead.

Add a stacking test to verify this scenario (was failing before of this
commit).

Fixes https://gitlab.gnome.org/GNOME/mutter/issues/885
https://gitlab.gnome.org/GNOME/mutter/merge_requests/895

[1] https://standards.freedesktop.org/wm-spec/wm-spec-latest.html#idm140200472512128
2019-11-07 16:04:19 +00:00
Marco Trevisan (Treviño)
c85fb107c0 window-props: Don't look for parent multiple times
Once we set the transient_for, we look for parent MetaWindow, so instead
of overwriting this value for loops check, just use another function
and avoid to look for the xwindow again when setting the MetaWindow parent.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/895
2019-11-07 16:04:19 +00:00
Marco Trevisan (Treviño)
13f10e36e4 window: Assert we only set a NULL workspace when unmanaging
There might be cases in which a window might be marked as both not in all
workspaces and with NULL workspace.

So to avoid this to happen, let's just assert early instead of doing this at
later point where the context might not be clear.

Related to https://gitlab.gnome.org/GNOME/mutter/issues/885

https://gitlab.gnome.org/GNOME/mutter/merge_requests/895
2019-11-07 16:04:19 +00:00
Marco Trevisan (Treviño)
2644e54c51 window: Warn if O-R window workspace state is used
Override-redirect windows have no workspace by default, and can't be parent
of a top-level window, so we must check that the parent window is not an
O-R one when setting the workspace state.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/895
2019-11-07 16:04:19 +00:00
Jonas Ådahl
0e5a5df5fe wayland/actor-surface: Always store away frame callbacks on commit
We're expected by MetaWaylandSurface to always pick the frame callbacks
out from the pending state when committing (applying) so that no frame
callbacks are unaccounted for. We failed to do this if our actor for
some reason (e.g. associated window was unmanaged) was destroyed. To
handle this situation better, store away the frame callbacks until we
some later point in time need to pass them on forward.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/893
2019-11-07 12:56:58 +00:00
Adam Jackson
806ebc464a cogl: Remove cogl_texture_2d_gl_new_from_foreign
As noted in <cogl-texture-2d-gl.h> (now also removed), this is for
allowing external GL callers to promote one of their textures to a
CoglTexture. We aren't doing that and don't want to start.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/883
2019-11-07 12:47:23 +00:00
Adam Jackson
54ac1f6b59 test: Remove unreferenced test-texture-rectangle
This isn't even built, and it's testing GL_TEXTURE_RECTANGLE_ARB, which
is not even a code path we support anymore since we require real NPOT.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/883
2019-11-07 12:47:23 +00:00
Adam Jackson
9b16b74b5d cogl: Remove unused stuff from cogl-material-compat.[ch]
You could probably move (most of) what's left into a static-inline kind
of header that only gets consumed by the tests.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/922
2019-11-07 12:33:35 +00:00
Florian Müllner
9172901458 ci: Fix checkout out gnome-shell on stable branches
For stable branches, we currently only check out the correct shell
branch for merge requests. For the regular pipeline, our code to
determine the current mutter branch fails because CI runs on a
temporary "pipeline/12345" branch that doesn't exist for gnome-shell.

Switching to the correct gitlab environment variable fixes that.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/811
2019-11-07 00:06:25 +01:00
Marco Trevisan (Treviño)
ffa0a24848 x11-display: Get next serial just before using it
We ask XLib the next request serial number before performing other actions
triggered by meta_x11_display_set_input_focus_internal() that doesn't use
the request serial anyways. So, just request it before updating the focus
window as that's the operation that needs it.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/909
2019-11-06 17:32:29 +00:00
Marco Trevisan (Treviño)
efe5bed5b4 x11-display: Don't unset the X11 focused window after setting one
When using DesktopIcons extension and clicking in an icon, gnome-shell
starts an infinite loop caused by the first focus change that may trigger
on X11 a focus in/out event that leads to stage activation/deactivation
which never ends.

This happens because as part of meta_x11_display_set_input_focus_xwindow()
to focus the X11 stage window, we unset the display focus, but this also
causes to request the X11 display to unset the focus since we convolute by
calling meta_x11_display_set_input_focus() with no window, that leads to
focusing the no_focus_window and then a focus-in / focus-out dance that the
shell amplifies in order to give back the focus to the stage.

In order to fix this, mimic what meta_display_set_input_focus() does, but
without updating the X11 display, and so without implicitly calling
meta_x11_display_set_input_focus(), stopping the said convolution and
properly focusing the requested xwindow.
Also ensure that we're not doing this when using an older timestamp, since
this check isn't performed anymore.

Fixes https://gitlab.gnome.org/GNOME/mutter/issues/896
Fixes https://gitlab.gnome.org/GNOME/mutter/issues/899

https://gitlab.gnome.org/GNOME/mutter/merge_requests/909
2019-11-06 17:32:29 +00:00
Carlos Garnacho
e865fcc460 wayland: Check focus surface client in wl_data_device.set_selection()
Similar to our handling in set_primary(), ignore set_selection() requests
that come from unfocused clients.

https://gitlab.gnome.org/GNOME/mutter/issues/878
2019-11-06 15:59:16 +01:00
Carlos Garnacho
16eb461054 wayland: Clean up meta_wayland_data_device_set_primary()
This function is already checking for the focus surface client
matching the requestor. The type check was slightly bogus though
as it'd be an screwup in our code, make it an assert instead.

Also, move the check for the client having the focus into the
upper call, so this and wl_data_device.set_selection code can
get more in line.

https://gitlab.gnome.org/GNOME/mutter/issues/878
2019-11-06 15:59:16 +01:00
Carlos Garnacho
c11ef6ef07 wayland: Flatten data source object hierarchy
We have an abstract MetaWaylandDataSource and 2 subclasses for
clipboard/primary data sources. Since the abstraction provided
by the additional sublevel is arguable, push the wl_resource
field up, and leave us with just 2 objects to think about, all
of them containing a wl_resource.

https://gitlab.gnome.org/GNOME/mutter/issues/878
2019-11-06 15:59:16 +01:00
Thomas Hindoe Paaboel Andersen
95eda361c1 wayland: use correct enum type for tablet pad
Fixes a compile warning.  The two enums are identical, so no
functional change intended.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/863
2019-11-05 13:07:47 +00:00
Jonas Ådahl
662c76c4fc tests/monitor-unit-tests: Add another tiling window hot plug test
Checks that we handle hot plugs of a untiled window, that was previously
tiled.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:36:25 +01:00
Jonas Ådahl
ff799a1abe window: Reset tile monitor number when untiling
Otherwise we'll end up trying to access the out of date state later.

Fixes the following test failure backtrace:

    #0  _g_log_abort ()
    #1  g_logv ()
    #2  g_log ()
    #3  meta_monitor_manager_get_logical_monitor_from_number ()
    #4  meta_window_get_work_area_for_monitor ()
    #5  meta_window_get_tile_area ()
    #6  constrain_maximization ()
    #7  do_all_constraints ()
    #8  meta_window_constrain ()
    #9  meta_window_move_resize_internal ()
    #10 meta_window_tile ()

https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:36:25 +01:00
Jonas Ådahl
155b7bf569 tests/monitor-unit-tests: Add window tiling hot plug test
This test that we handle hot plugs correctly together with tiled
windows.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:36:25 +01:00
Jonas Ådahl
47155ed524 tests/runner: Move window shown synchronization to helper
https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:35:00 +01:00
Jonas Ådahl
db91439bb0 tests/monitor-unit-tests: Move test client sanity check into helper
https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:35:00 +01:00
Jonas Ådahl
77aad0869f window: Always update tile monitor number on hot plug
Otherwise we'll end up crashing if we had two connected monitors,
unplugged both, then replugged in a single one.

Avoids the following error:

    #0  _g_log_abort ()
    #1  g_logv ()
    #2  g_log ()
    #3  meta_monitor_manager_get_logical_monitor_from_number ()
    #4  meta_window_get_work_area_for_monitor ()
    #5  meta_window_get_tile_area ()
    #6  constrain_maximization ()
    #7  do_all_constraints ()
    #8  meta_window_constrain ()
    #9  meta_window_move_resize_internal ()
    #10 meta_window_move_resize_frame ()
    #11 meta_window_move_resize_now ()
    #12 idle_move_resize ()
    #13 call_idle_later ()

https://bugzilla.redhat.com/show_bug.cgi?id=1767703

https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:35:00 +01:00
Jonas Ådahl
dc1a28c42a plugins/default: Clean up tile preview when closing display
On finalize, the preview actor will have been destroyed behind our back;
avoid that by cleaning up before it's too late.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:35:00 +01:00
Jonas Ådahl
955b27637c plugin/default: Init quark before using
Cut lines in pieces, and remove useless "optimizations" while at it

https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:35:00 +01:00
Jonas Ådahl
1f5b403524 display: Add 'closing' signal
Emitted when the MetaDisplay is closing. Meant for clean up that depends
on things that will be torn down during closing.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/912
2019-11-05 10:35:00 +01:00
Robert Mader
5e87d67e5f surface-actor-wayland: Do not send frame callbacks if the actor is obscured
`meta_surface_actor_is_obscured` implies that the actor got successfully culled
out and nothing of it will get painted. This includes that there are no clones,
no effects etc. In this cases we don't want to send frame callbacks, thus avoiding
unnecessary client work.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/918
2019-11-04 16:06:37 +01:00
Marco Trevisan (Treviño)
f133de2dd4 clutter/actor: Unref the root node if set as child
When setting the root node as child of a clip or transform node, we add a
new reference to it, without removing the one that we've previously added
when getting it from the actor node (and that won't ever be unset by the
auto-pointer since the root_node is re-associated).

So, once we add the root node as child and re-define it, unref it.

Fixes https://gitlab.gnome.org/GNOME/mutter/issues/908
2019-11-04 12:07:43 +00:00
Olivier Fourdan
60800d2313 renderer-native: Separate offscreen and shadowfb
Create the intermediate shadow framebuffer for use exclusively when a
shadowfb is required.

Keep the previous offscreen framebuffer is as an intermediate
framebuffer for transformations only.

This way, we can apply transformations between in-memory framebuffers
prior to blit the result to screen, and achieve acceptable performance
even with software rendering on discrete GPU.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/877
2019-11-04 10:44:42 +01:00
Olivier Fourdan
db90c0d509 clutter/stage-view: Separate offscreen and shadowfb
Previously, we would use a single offscreen framebuffer for both
transformations and when a shadow framebuffer should be used, but that
can be dreadfully slow when using software rendering with a discrete GPU
due to bandwidth limitations.

Keep the offscreen framebuffer for transformations only and add another
intermediate shadow framebuffer used as a copy of the onscreen
framebuffer.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/877
2019-11-04 10:44:42 +01:00
Adam Jackson
e5b0f474ab cogl: Remove some unused framebuffer API
https://gitlab.gnome.org/GNOME/mutter/merge_requests/913
2019-11-01 16:48:12 -04:00
Carlos Garnacho
1688cf7c44 clutter: Drop the no-clear stage hint
A compositor is notably opaque (usually has nothing to be painted on!).
gnome-shell sets this hint, but there's no reason why we wouldn't want
it by default.

Also, the color buffer being cleared messes with stencil clips, as the
clear operation by definition ignores the stencil buffer. We want to
use these more extensively in the future, so just drop this API.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/911
2019-11-01 15:02:09 +00:00
Carlos Garnacho
2202c0d02e tests: Explicitly set a background color for offscreen actor tests
Those change opacity and read pixels, relying on an implicit stage color.
We won't do that anymore.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/911
2019-11-01 15:02:09 +00:00
Hans de Goede
dbb95cbe5f window-xwayland: Add Xwayland fullscreen games workaround
This is a workaround for X11 games which use randr to change the resolution
in combination with NET_WM_STATE_FULLSCREEN when going fullscreen.

Newer versions of Xwayland support the randr part of this by supporting randr
resolution change emulation in combination with using WPviewport to scale the
app's window (at the emulated resolution) to fill the entire monitor.

Apps using randr in combination with NET_WM_STATE_FULLSCREEN expect the
fullscreen window to have the size of the emulated randr resolution since
when running on regular Xorg the resolution will actually be changed and
after that going fullscreen through NET_WM_STATE_FULLSCREEN will size
the window to be equal to the new resolution.

We need to emulate this behavior for these games to work correctly.

Xwayland's emulated resolution is a per X11 client setting and Xwayland
will set a special _XWAYLAND_RANDR_EMU_MONITOR_RECTS property on the
toplevel windows of a client (and only those of that client), which has
changed the (emulated) resolution through a randr call.

This commit checks for that property and if it is set adjusts the fullscreen
monitor rect for this window to match the emulated resolution.

Here is a step-by-step of such an app going fullscreen:
1. App changes monitor resolution with randr.
2. Xwayland sets the _XWAYLAND_RANDR_EMU_MONITOR_RECTS property on all the
   apps current and future windows. This property contains the origin of the
   monitor for which the emulated resolution is set and the emulated
   resolution.
3. App sets _NET_WM_FULLSCREEN.
4. We check the property and adjust the app's fullscreen size to match
   the emulated resolution.
5. Xwayland sees a Window at monitor origin fully covering the emulated
   monitor resolution. Xwayland sets a viewport making the emulated
   resolution sized window cover the full actual monitor resolution.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/739
2019-11-01 14:14:21 +01:00
Hans de Goede
ae238d1d4d window: Add adjust_fullscreen_monitor_rect virtual method
Add an adjust_fullscreen_monitor_rect virtual method to MetaWindowClass
and call this from setup_constraint_info() if the window is fullscreen.

This allows MetaWindowClass to adjust the monitor-rectangle used to size
the window when going fullscreen, which will be used in further commits
for a workaround related to fullscreen games under Xwayland.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/739
2019-11-01 14:12:17 +01:00
Christian Hergert
6051712919 profiler: track changes in GLib and Sysprof
This tracks the changes to gdbus-codegen in terms of how GUnixFDList is
done to use the UnixFD annotation.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/908
2019-10-30 16:07:36 -07:00
Carlos Garnacho
6bfa61a3a7 Revert "clutter/cogl: Store empty clip regions for buffer age"
This reverts commit 4918893326.

This commit prevented cogl_stage_cogl_redraw_view() from skipping
swap buffers entirely if the invalidation region ended up empty.
This meant we were actually swapping buffers when we didn't need to.

The source of the glitches was fixed more properly, so this just adds
extra work.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/898
2019-10-30 17:17:29 +00:00
Carlos Garnacho
cf89e4d2cd clutter/cogl: Fix invalidation on non-primary monitors with no buffer age
We passed the view rectangle, we however want a fb-scaled rectangle starting
at 0,0. Fixes invalidation on other than the primary monitor when those
paths are hit.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/898
2019-10-30 17:17:29 +00:00
Carlos Garnacho
d47324e8d7 cogl/egl: Explicitly initialize age variable
In case of error, it's untouched by EGL, which probably means an
invalid read.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/906
2019-10-30 17:09:03 +00:00
Carlos Garnacho
ee4638ef5c cogl/egl: Make surface current before querying buffer age
Unknown since when, we started deferring the eglMakeCurrent for the
current framebuffer till we started painting on it, which means we
are preparing for rendering a view without guarantees that the
framebuffer we will paint to is the current drawing surface for the
EGL context.

A fairly common case where that assumption will break is multimonitor
set ups, in this case we will be preparing to paint to a view while
the current draw surface is that of the previously rendered view's.

Mesa will in this case return EGL_BAD_SURFACE when querying the buffer
age, since the surface is not yet the current draw surface. This
makes us give up on buffer age checks, and paint the whole view. Since
the problem repeats when painting the next view, we are effectively
doing full-screen redraws on all monitors.

Since cogl usually works implicitly, and querying the buffer age is
meaningless if you're not meant to paint on a surface, make the surface
the current draw surface implicitly before querying the buffer age.

This brings us glorious partial invalidations back when several views
had to be repainted.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/906
2019-10-30 17:09:03 +00:00
Carlos Garnacho
6ee7c0f486 cogl/egl: Warn when we fail to query a buffer age.
In order to avoid log spamming, just warn once it starts to happen, not
on every frame for every onscreen. Just knowing that this is happening
is a hint that something's going wrong.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/906
2019-10-30 17:09:03 +00:00