check_monitor_test_clients_state() is a function that's only meant to be
used in the monitor-unit-tests, and since we're going to move the
functions for creating MonitorTestSetups into a common file, this
function is going to be in the way of that. So move the checking of the
test client state outside of check_monitor_test_clients_state().
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1243
We're going to move the functions for building MonitorTestSetups to the
common monitor-test-utils.c file.
To make building test setups a bit more straightforward in case no
TestCaseExpect is wanted, change create_monitor_test_setup() to take a
MonitorTestCaseSetup instead of a MonitorTestCase as an argument.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1243
Commit e06daa58c3 changed the tested values to use corresponding valid
enum values instead of negative ones. Unfortunately that made one value
become a duplicate of an existing one and also in part defeated the original
intention of checking the implementation of
`meta_output_crtc_to_logical_transform`.
Use `meta_monitor_transform_invert` to fix both shortcomings.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1242
One of the important classes in Mutter's handling of client textures is
the `MetaShapedTexture`. This commit adds a few gtk-doc comments which
explain its purpose, with special attention to the viewport methods.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1210
Since we're now connecting to one more signal of MetaWaylandOutput, keep
signal connections in one place and move connecting the
"output-destroyed" signal to surface_entered_output() and disconnecting
it to surface_left_output().
This also allows us to use the "outputs_to_destroy_notify_id" as a
simple set and rename it to "outputs".
While at it, also use g_hash_table_destroy() instead of
g_hash_table_unref() since destroy is more clear than unref and does the
same thing in this case.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1230
When hotplugging a new monitor, we recreate all the MetaWaylandOutputs
and need to emit leave events to the surfaces for the old wl_outputs and
enter events for the newly created ones.
There's a race condition though: We might update the monitors a surface
is on (and thus emit enter/leave events for the wl_outputs) before the
Wayland client is registered with the new wl_output (ie. the
bind_output() callback of MetaWaylandOutput was called), which means we
don't send an enter event to the client in surface_entered_output().
Since MetaWaylandSurface now has the MetaWaylandOutput in its outputs
hashtable, it thinks the client has been notified and won't send any
more enter events.
To fix that, make MetaWaylandOutput emit a new signal "output-bound"
when a client bound to the output and make all surfaces which are on
that output listen to the signal. In the signal handler compare the
newly added client to the client the surface belongs to, and if it's the
same one, send an enter event to that client.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1230
The "output-destroyed" signal is used for notifying MetaWaylandSurfaces
that an output they are shown just got invalid (for example because a
monitor hotplug happened).
While we delay the destroying of outputs by 10 seconds since commit
1923db97 because of a race-condition, it doesn't make sense to wait 10
seconds until we let surfaces know that an output was destroyed.
So move the emission of the "output-destroyed" signal to
make_output_inert(), which is called before we start the 10 seconds
delay.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1230
When tiling, we want to set the tile monitor. To not have to do this
from the call site, make meta_window_tile() fall back to the current
monitor if nothing set it prior to the call.
This will make it more convenient for test cases to test tiling
behavior.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
The test tests that (for both X11 and Wayland) that:
* The client unmaximizes after mapping maximized to a predictable size
* That the client unmaximizes to the same size after toggling maximize
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
This makes sure that a client has properly responded to a configure
event it itself triggered. In practice, this is just two 'wait'
commands, with a 'dispatch' in between, which is needed because a single
one does not reliably include the two way round trip happening when e.g.
responding to a unmaximize configure event triggered by a unmaximize
request.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
The 'assert_size' command checks that the size of the window, both
client side and compositor side, corresponds to an expected size set by
the test case.
The size comparison can only be done when the window is using 'csd', in
order for both the client and server to have the same amount of
understanding of the title bar. For ssd, the client cannot know how
large the title bar, thus cannot verify the full window size.
Sizes can be specified to mean the size of the monitor divided by a
number. This is that one can make sure a window is maximized or
fullscreened correctly.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
Gtk is quite buggy and "fluid" in how it handles the shadow margins for
windows under X11. The "size" of the window fluctuate between including and
excluding a shadow margin in a way that causes issues, as there are no
atomic update of any state going on.
In order to avoid running into those particular issues now, lets get rid
of shadows so the margins are always zero, when the client is using the
X11 backend.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
To get some kind of consistency between what 'resize' means for the
compositor and the client, make the size correspond to the "frame rect"
of the window, i.e. the window geometry in the Wayland case, and the
window size including the titlebar in the X11 case.
This is so that the window size later can be reliably compared both in
the compositor and in the client using the same expected dimensions.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
When toying with the test client to try to reproduce issues (e.g.
writing commands on stdin to create and manipulate windows), when you
write a command incorrectly you'll get a warning printed to standard
out. The problem, however, is that it doesn't include a line break in
the end, meaning when you type the correct command, it won't be on a new
line.
Fix this minor annoyance by adding line breaks to all warning messages.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
The test client could already understand the resize command, but they
could not be added to metatests as the command was not properly plumbed
via the test runner. Establish the plumbing for the resize command so
that resize tests can be added.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1171
This removes ClutterAnimation and related tests. ClutterAnimation has
been deprecated for a long time, and replacements exist and are used by
e.g. GNOME Shell since a while back.
This also disables a few relatively unrelated interactive tests, as they
rely on ClutterAnimation to implement some animations they use to
illustrate what they actually test.
As interactive tests currently are more or less untestable due to any
interaction with them crashing, as well as they in practice means
rewriting the tests using non-deprecated animation APIs, they are not
ported right now. To actually port the interactive tests, it needs to be
possible to fist interact with them.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1192
When memfd_create isn't used, the file isn't sealed. Therefore, we
should skip test_readonly_seals on the fallback case. This fixes
compilation error on FreeBSD 12, which does not support memfd_create.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1229
We were iterating through evcodes, but using API that expects Clutter button
numbers. Instead of transforming those to Clutter numbers to have those translated
back, use the inner seat API that already takes evcodes.
Fixes stuck buttons keys after a virtual device is destroyed while those are
pressed.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1239
Move to center uses all monitors for calculating work area.
This can lead to an unexpected behaviour on some monitor
configurations resulting in current window being split between
monitors. We should move window to the center of the active display.
Closes https://gitlab.gnome.org/GNOME/mutter/-/issues/1073
Inhibiting remote access means any current remote access session is
terminated, and no new ones can be created, until remote access is
uninhibited. The inhibitation is ref counted, meaning there can be more
than one inhibitor.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1212
When resizing an X11 window with client side decorations, the shadow is
clipped by the frame bounds so that we don't need to paint the shadow
under the opaque areas covered by the window and its frame.
When the X11 client uses the EMWH synchronization mechanism (like all
gtk-3 based clients), the actual window may not be updated so that the
actual window and it frame may be behind the expected window frame
bounds, which gives the impression of de-synchronized shadows.
To avoid the issue, keep a copy of the frame bounds as a cache and only
update it when the client is not frozen so that the clipping occurs on
the actual content.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/1178https://gitlab.gnome.org/GNOME/mutter/merge_requests/1214
It takes coordinates in stage coordinate space, and will result in
a screen cast stream consisting of that area, but scaled up by the scale
factor of the view that overlaps with the area and has the highest scale
factor.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1207
Will be used by the stage to not paint the overlays. We skip all
overlays since overlays are only ever used for pointer cursors when the
hardware cursors cannot or should not be used.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1207
These phase callbacks are not intended to be inovked when something
secondary is painting the stage, such as a screen cast stream, or
similar. Thus, only invoke the callbacks when there is a view associated
with the paint context, which will not be the case for offscreen
painting.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1207
If there is a paint context available (i.e. for the phases that are
during the actual stage paint), pass it along the callbacks, so that
the callback implementations can change their operation depending on the
paint context state.
This also means we can get the current view from the paint context,
instead of the temporarily used field in the instance struct.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1207
A paint flag affects a paint operation in ways defined by the flags.
Currently no flags are defined, so no semantical changes are defined
yet. Eventually a flag aiming to avoid painting of cursors is going to
be added, so that screen cast streams can decide whether to include a
cursor or not.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1207
If drmModePageFlip() or custom_page_flip_func fails, process_page_flip() was
forgetting to undo the ref taken for that call. This would leak page_flip_data.
The reference counting works like this:
- when created, ref count is 1
- when calling drmModePageFlip, ref count is increased to 2
- new: if flip failed, ref count is decreased back to 1
- if calling schedule_retry_page_flip(), it takes a ref internally
- if calling mode_set_fallback(), it takes a ref internally
- all return FALSE paths have an explicit unref
- return TRUE path has an explicit unref
This issue was found by code inspection and while debugging an unrelated issue
with debug prints sprinkled around. I am not aware of any end-user visible
issues being fixed by this, as the leak is small and probably very rare.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1209
When testing a laptop with intel and DisplayLink devices, attempting to set the
DL output as the only active output resulted in GNOME/Wayland freezing. The
main event loop was running fine, but nothing on screen would get updated once
the DL output become the only one. This patch fixes that issue.
DisplayLink USB 3 devices use an out-of-tree kernel DRM driver called EVDI.
EVDI can sometimes fail drmModePageFlip(). For me, the flip fails reliably when
hotplugging the DL dock and when changing display configuration to DL only.
Mutter has a workaround for failing flips, it just calls drmModeSetCrtc() and
that succeeds.
What does not work reliably in the fallback path is Mutter keeping track of the
pageflip. Since drmModePageFlip() failed, there will not be a pageflip event
coming and instead Mutter queues a callback in its stead. When you have more
than one output, some other output repainting will attempt to swap buffers and
calls wait_for_pending_flips() which has the side-effect of dispatching any
queued flip callbacks. With multiple outputs, you don't get stuck (unless they
all fail the exact same way at the same time?). When you have only one output,
it cannot proceed to repaint and buffer swap because the pageflip is not marked
complete yet. Nothing dispatches the flip callback, leading to the freeze.
The flip callback is intended to be an idle callback, implemented with a
GSource. It is supposed to be called as soon as execution returns to the main
event loop. The setup of the GSource is incomplete, so it will never dispatch.
Fix the GSource setup by setting its ready-time to be always in the past. That
gets it dispatched on the next cycle of the main event loop. This is now the
default behavior for all sources created by meta_kms_add_source_in_impl().
Sources that need a delay continue to do that by overriding the ready-time
explicitly.
An alternative solution could have been to implement GSource prepare and check
callbacks returning TRUE. However, since meta_kms_add_source_in_impl() is used
by flip retry code as well, and that code needs a delay through the ready-time,
I was afraid I might break the flip retry code. Hence I decided to use
ready-time instead.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1209
According to the XSetSelectionOwner libX11 documentation:
[...] If the owner window it has specified in the request is later
destroyed, the owner of the selection automatically reverts to None,
but the last-change time is not affected.
This is indeed visible through the selection_timestamp field in
XFixesSelectionNotify events.
Use this to check whether the selection time is recent-ish (thus
likely coming from an explicit XSetSelectionOwner request) and honor
the client intent by setting a "NULL" owner. If the selection time
is too old, it's definitely an indication of the owner client being
closed, the scenario where we do want the clipboard manager to take
over.
This fixes two usecases:
- X11 LibreOffice / WPS clear the selection each time before copying
its own content. Mutter's clipboard manager would see each of those
as a hint to take over, competing with the client over selection
ownership. This would simply no longer happen
- Password managers may want to clear the selection, which would be
frustrated by our clipboard manager.
There's a slight window of opportunity for the heuristics to fail
though, if a X11 client sets the selection and closes within 50ms, we
would miss the clipboard manager taking over.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1206
The X11 selection source was being preserved after unsetting its
ownership. This is no leak as it would be eventually replaced by
another source, or destroyed on finalize. But it's pointless to
keep it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1206
Test the two modes of MetaAnonymousFile, MAPMODE_SHARED and
MAPMODE_PRIVATE and make sure they don't leak data to other FDs when
writing to an FD provided by `meta_anonymous_file_get_fd` even though
the data of both FDs is residing in the same chunk of memory.
We do all the reading tests using mmap instead of read() since using
read() on shared FDs is going to move the read cursor of the fd. That
means using read() once on the shared FD returned by
meta_anonymous_file_get_fd() in MAPMODE_PRIVATE breaks every subsequent
read() call.
Also test the fallback code of MetaAnonymousFile in case `memfd_create`
isn't used for the same issues.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1012
Add MetaAnonymousFile, an abstraction around anonymous read-only files.
Files can be created by calling meta_anonymous_file_new(), passing the
data of the file. Subsequent calls to meta_anonymous_file_open_fd()
return a fd that's ready to be sent over the socket.
When mapmode is META_ANONYMOUS_FILE_MAPMODE_PRIVATE the fd is only
guaranteed to be mmap-able readonly with MAP_PRIVATE but does not
require duplicating the file for each resource when memfd_create is
available. META_ANONYMOUS_FILE_MAPMODE_SHARED may be used when the
client must be able to map the file with MAP_SHARED but it also means
that the file has to be duplicated even when memfd_create is available.
Pretty much all of this code was written for weston by Sebastian Wick,
see https://gitlab.freedesktop.org/wayland/weston/merge_requests/240.
Co-authored-by: Sebastian Wick <sebastian@sebastianwick.net>
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1012
Instead of having everything clumped at MetaWaylandDataManager,
split the primary selection to its own struct. This manager is
handled separately from wl_data_device_manager and other selection
managers, so they would be able to interoperate between them, even.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1193
This is still an openly defined struct, as we will need accessed
by "subclasses". Same principle applies than with the
MetaWaylandDataSource refactor, this is not meant to introduce
functional changes, so just go with it.
On the bright side, the interactions are now clearer, so it could
be made saner in the future.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1193
The split wasn't 100% clean, and some extra private API had to be
added for it (but well, looking at the API, it's already evident
there's a cleanup/streamlining task due). This is meant to be a
refactor with no functional changes, so just go with it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1193
We already have a signal callback that translates selection ownership changes to
data_device/primary .selection events. Given both will be run when a data source
is being replaced, and this event emission being deleted is kinda short sighted
in that in only knows about Wayland, rely entirely on MetaSelection::owner-changed
emission.
Fixes spurious .selection(null) events being sent when a compositor-local source
takes over the selection without the focus changing (eg. screenshot to clipboard).
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1160https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1204
We are meant to send a .cancelled event after the drop is performed
in certain situations, but only for version>3 clients. Since this is
all version 3 business, only set the drop_performed flag for v3
clients. This drops the need to perform version checks at the time
of cancelling (which is present for other usecases in v1).
Fixes emission of wl_data_source.cancelled for v1 clients.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1177https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1203
For the cases where we read a fixed size from the selection (eg. imposing
limits for the clipboard manager), g_input_stream_read_bytes_async() might
not read up to this given size if the other side is spoonfeeding it content.
Cater for multiple read/write cycles here, until (maximum) transfer size is
reached.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
Flushing the X11 selection output stream may happen synchronously or
implicitly, in which case there is not a task to complete. Check there
is actually a task before returning errors. We additionally set the
pipe_error flag, so future operations will fail with an error, albeit
with a more generic message.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
If a write_async() comes up while we are flushing on the background,
the task will be queued, but not deemed a reason on itself to keep
flushing (and finish the task) after a property delete event.
To fix this, do not ever queue up write_async tasks (this leaves
priv->pending_task only used for flush(), so the "flush to end"
behavior in the background is consistent). We only start a
background flush if there's reasons to do it, but the tasks are
immediately finished.
All data will still be ensured to be transfered on flush/close,
this makes the caller in this situation still able to reach to it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
It does not make sense to check for the stream not being closed,
this might happen multiple times during the lifetime of the stream
for a single transfer. We want to notify the INCR transfer just
once.
Check for the explicit conditions that we want, that the remaining
data is bigger than we can transfer at once, and that we are not
yet within the INCR transfer.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
The stream automatically flushes after data size exceeds the
size we deem for INCR chunks, but we still try to copy it all.
Actually limit the data we copy, and leave the rest for future
INCR chunks.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
INCR transfers are mandated to finish with a final 0-size XChangeProperty
roundtrip after the final data chunk. Actually honor this and ensure we
iterate just once more for this.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
This seemed to work under the assumption that a flush() call can
only result in one INCR roundtrip. This is evidently not true, so
we should hold things off until all pending data is actually flushed.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
If say we want 32bit data, but have 2 bytes stored, we would simply
ignore flush requests. Allow (and don't clear) the needs_flush flag
if we have less than the element size accumulated.
Instead handle this in can_flush(), so it's triggered whenever we
have enough data to fill 1 element, or if the stream is closing
(seems a broken situation, but triggered by the caller).
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
XMaxRequestSize/XMaxExtendedRequestSize are documented to return
the maximum size in 4-byte units, whereas we are comparing this
to byte lenghts. We can afford 4x the data here.
Since I don't know the payload size of the XChangeProperty request,
be generous and allot 400 bytes for it, we have some to spare.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1198
When closing the lid of a laptop, we reconfigure all the monitors in order
to update the CRTCs and (if enabled) the global UI scaling factor.
To do this, we try first to reuse the current configuration for the usable
monitors, but if we have only monitor enabled and this one is on the laptop
lid we just end up creating a new configuration where the primary monitor is
the laptop one (as per find_primary_monitor() in MetaMonitorConfigManager),
but ignoring the user parameters.
In case the user selected a different resolution / scaling compared to the
default one, while the laptop lid is closed we might change the monitors
layout, causing applications to rescale or reposition.
To avoid this, when creating the monitors configuration from the current
current state, in case we have only one monitor available and that one is
the laptop panel, let's just reuse this configuration.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1200
Try to bypass compositing if there is a fullscreen toplevel window with
a buffer compatible with the primary plane of the monitor it is
fullscreen on. Only non-mirrored is currently supported; as well as
fullscreened on a single monitor. It should be possible to extend with
more cases, but this starts small.
It does this by introducing a new MetaCompositor sub type
MetaCompositorNative specific to the native backend, which derives from
MetaCompositorServer, containing functionality only relevant for when
running on top of the native backend.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
We need to coordinate with MetaCompositor during pre-paint so that we
have control over whether MetaLater callbacks happen first, or the
MetaCompositor pre-paint logic.
In order to do so, make MetaLater listen to a new signal "pre-paint" on
MetaCompositor, that is called MetaCompositors own pre-paint handling.
This fixes an issue where the top window actor was calculated after the
MetaCompositor pre-paint handling, meaning the top actor being painted
was out-of-date.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
Since the order of destruction during MetaDisplay tear down is a bit
unordered, there are pieces that try to destruct its compositing
dependent pieces (i.e. queued MetaLater callbacks) after MetaCompositor
has been cleaned up, meaning we need to put some slightly awkward NULL
checks to avoid crashing.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
MetaCompositor is the place in mutter that manages the higher level
state of compositing, such as handling what happens before and after
paint. In order for other units that depend on having a compositor
instance active, but should be initialized before the X11 implementation
of MetaCompositor registers as a X11 compositing manager, split the
initialization of compositing into two steps:
1) Instantiate the object - only construct the instance, making it
possible for users to start listening to signals etc
2) Manage - this e.g. establishes the compositor as the X11 compositing
manager and similar things.
This will enable us to put compositing dependent scattered global
variables into a MetaCompositor owned object.
For now, compositor management is internally done by calling a new
`meta_compositor_do_manage()`, as right now we can't change the API of
`meta_compositor_manage()` as it is public. For the next version, manual
management of compositing will removed from the public API, and only
managed internally.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
While at it, fix some style inconsistencies, for now use a single
singleton struct instead of multiple static variables, and
other non-functional cleanups. Semantically, there is no changes
introduced.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
This will check whether the current backing buffer is compatible with
the primary plane of the passed CoglOnscreen. Since this will extend the
time before a buffer is released, the MetaWaylandBufferRef is swapped
and orphaned if a new buffer is committed before the previous one was
released. It'll eventually be released, usually by the next page flip
callback.
Currently implemented for EGLImage and DMA-BUF buffer types.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
Advertising support for modifiers means we will most likely not not be
able to scan out client buffers directly, meaning it just as likely that
we won't be able to scan out even fullscreen windows without atomic KMS.
When we have atomic support, we should advertise support for modifiers
if atomic is used to drive the CRTCs, as we by then can check whether we
can scan out directly, place in an overlay plane, etc.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
While this is fairly incomplete, as to check things fully we need to use
TEST_ONLY in atomic to try out a complete assignment on the device, but
this works well enough for legacy non-modifier cases.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
Instead of always swapping buffers and flipping the back buffer, make it
possible to scan out a provided buffer directly without swapping any EGL
buffers.
A buffer is passed as an object implementing the empty CoglScanout
interface. It is only possible to do this in the native backend; and the
interface is implemented by MetaDrmBufferGbm. When directly scanned out,
instead of calling gbm_surface_lock_front_buffer() to get the gbm_bo and
fbid, get it directly from the MetaDrmBufferGbm, and use that to create
the page flip KMS update.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
