This prevents screencopy applications from hanging because a failed
event never got sent when the output was disconnected or disabled after
the call to buffer().
The documentation for wayland-server.h says:
> Use of this header file is discouraged. Prefer including
> wayland-server-core.h instead, which does not include the server protocol
> header and as such only defines the library PI, excluding the deprecated API
> below.
Replacing wayland-server.h with wayland-server-core.h allows us to drop the
WL_HIDE_DEPRECATED declaration.
AFAIK this was always set to zero. Instead, compute wl_output mode flags on the
fly.
Technically this is a breaking change, but I don't think anybody uses this
field.
This commit matches sway's 2dc4978d8af326c310057ca8fd22a4c7f5d09335.
To help ensure a reproducible build (when debug info is disabled),
the meson build script now uses the -fmacro-prefix-map command line
argument supported by GCC to strip the build-path dependent bytes
of each __FILE__ string used by wlr_log and related functions.
A rather ugly algorithm is used to compute the relative path between
the build and source folders, because meson has no specific function
for this.
When the compiler does not support -fmacro-prefix-map, fall back
to shifting the start of each __FILE__ string by the length of the
relative path to the source directory.
This change tracks, for each wlr_seat_client, the most recent serial
numbers which were sent to the client. When the client makes a
selection request, wlroots now verifies that the serial number
associated with the selection request was actually provided to that
specific client. This ensures that the client that was most
recently interacted with always has priority for its copy selection
requests, and that no other clients can incorrectly use a larger serial
value and "steal" the role of having the copy selection.
Also, the code used to determine when a given selection is superseded
by a newer request uses < instead of <= to allow clients to make
multiple selection requests with the same serial number and have the
last one hold.
To limit memory use, a ring buffer is used to store runs of sequential
serial numbers, and all serial numbers earlier than the start of the
ring buffer are assumed to be valid. Faking very old serials is
unlikely to be disruptive.
Assuming all clients are correctly written, the only additional
constraint which this patch should impose is that serial numbers
are now bound to seats: clients may not receive a serial number
from an input event on one seat and then use that to request
copy-selection on another seat.
The backend doesn't need to handle transform changes, since everything is done
in software. In fact, all of the implementations were all identical and just
set the transform.
We could add support for hardware transforms, but:
- This would require a different field (something like hardware_transform)
- Not all combinations are possible because there often are hardware
limitations
- The Wayland protocol isn't ready for this (in particular xdg-output, see [1])
This belongs to a different patch series anyway.
[1]: https://patchwork.freedesktop.org/series/52324/
In addition to `button_count`, we keep track of the current buttons
pressed just as in `wlr_keyboard`.
Add `set_add` and `set_remove` to assist with this. These functions can
only be used with values greater than 0 (such as the button/key masks
for keyboards and pointers).
Partially addresses:
- https://github.com/swaywm/wlroots/issues/1716
- https://github.com/swaywm/wlroots/issues/1593
This commit introduces wlr_output_schedule_done and refactors the mechanism
used to send wl_output events to clients.
wlr_output_schedule_done schedules a wl_output.done event. This allows clients
to see wlr_output property changes as atomic.
This function is also useful for add-on interfaces like xdg_output which need
to trigger a wl_output.done event to apply their new state.
wlr_output_damage_make_current has been renamed to
wlr_output_damage_attach_render, since it's just a wrapper for
wlr_output_attach_render.
wlr_output_damage_swap_buffers has been removed completely. Instead,
wlr_output_damage now listens to successful wlr_output commits and updates its
internal state accordingly.
This updates the backend part of the output API. This is mostly renaming:
make_current becomes attach_render and swap_buffers becomes commit.
This also fixes the RDP backend to support NULL damage.
This is necessary for direct scan-out and other upcoming features. This patch
changes the output API to look like the wl_surface API.
Outputs now have some double-buffered state: the frame to be submitted
(currently only wlr_renderer frames are supported) and the damaged region.
To attach a pending frame, use wlr_output_attach_render. To set the pending
damaged region, use wlr_output_set_damage.
To submit the pending state, call wlr_output_commit. This will submit the
pending frame to the backend.
To migrate from the old API to the new one:
- Replace wlr_output_make_current calls by wlr_output_attach_render
- Replace wlr_output_swap_buffers calls by wlr_output_set_damage and
wlr_output_commit
The deleted includes are redundant, because other headers will include
the necessary files. Additionally, they cause build failures, because
including EGL/egl.h or EGL/eglext.h directly, instead of through
wlr/render/egl.h or wlr/render/interface.h, will mean that
MESA_EGL_NO_X11_HEADERS will not have been defined, and so the EGL
headers will attempt to pull in unnecessary X11 headers that may not
exist on the system.
For the headers produced by glgen.sh, the includes couldn't simply be
deleted, because no other header would include the EGL headers. Neither
wlr/render/egl.h or wlr/render/interface.h felt appropriate to include,
so I opted instead to copy the MESA_EGL_NO_X11_HEADERS definition before
the EGL includes.
* idle: enable the compositors to add custom idle timeouts
* idle: add a private constructor which also creates the resource
* idle: move resource creation to the idle implementation callback
This types adds a container for formats + modifiers.
A list that is of [format [modifier]] was chosen instead of
[format modifer] because that is how GBM accepts them.
Co-Authored-By: emersion <contact@emersion.fr>
Since the fullscreen request may be made before the toplevel's surface
is mapped, the requested fullscreen output needs to be stored so it
can be retrieved on map (along with the existing fullscreen property).
This commit makes the required changes for wlr_xdg_toplevel_v6.
Since the fullscreen request may be made before the toplevel's surface
is mapped, the requested fullscreen output needs to be stored so it
can be retrieved on map (along with the existing fullscreen property).
This commit makes the required changes for wlr_xdg_toplevel.
* wlr_output: Indicate modes link
* wlr_output: Introduce preferred flag
This indicates an outputs preferred mode.
* drm: Set preferred flag for an outputs preferred mode
This improves the way the output numbers are handled for the noop
backend. Instead of using the number of active outputs plus one, the
last used number is stored and new outputs will increment it. This
fixes the situation where you start with one output, create a second,
close the first, and create a third. Without this, both outputs will be
NOOP-2, which causes an issue since the identifier will also be
identical. With this, the last output is NOOP-3 and the outputs can be
distinguished.
This improves the way the output numbers are handled for the headless
backend. Instead of using the number of active outputs plus one, the
last used number is stored and new outputs will increment it. This
fixes the situation where you start with one output, create a second,
close the first, and create a third. Without this, both outputs will be
HEADLESS-2, which causes an issue since the identifier will also be
identical. With this, the last output is HEADLESS-3 and the outputs can
be distinguished.
This improves the way the output numbers are handled for the x11
backend. Instead of using the number of active outputs plus one, the
last used number is stored and new outputs will increment it. This
fixes the situation where you start with one output, create a second,
close the first, and create a third. Without this, both outputs will be
X11-2, which causes an issue since the identifier will also be
identical. With this, the last output is X11-3 and the outputs can be
distinguished.
This improves the way the output numbers are handled for the wayland
backend. Instead of using the number of active outputs plus one, the
last used number is stored and new outputs will increment it. This
fixes the situation where you start with one output, create a second,
close the first, and create a third. Without this, both outputs will be
`WL-2`, which causes an issue since the identifier will also be
identical. With this, the last output is `WL-3` and the outputs can be
distinguished.
On DRM resume, such as switching back to a TTY, the output needs to be
modeset to the current mode. However, wlr_output_set_mode will return
early when attempting to set the mode to the current mode. This just
steps around wlr_output_set_mode and calls drm_connector_set_mode
directly.
data-control: separate out a data_offer struct
This is a prerequisite to adding primary selection support.
data-control: separate out data_control_source
This is a prerequisite to adding primary selection support, since that
doesn't use wlr_data_source, but rather wlr_primary_selection_source.
Update the data-control protocol
data-control: add primary selection support
Merge create_offer and create_primary_offer
Extract code into data_control_source_destroy()
Fix pointer style
Move resource neutralization to destructor
Store wl_resource in the data_offer
Extract data_offer destruction into a function
It doesn't make sense to keep popups opened when unmapped. We also need to do
so in wlr_xdg_popup_destroy so that popups are destroyed in the correct order.
In order for a surface to be used as a cursor plane framebuffer, it
appears that requiring the buffer to be linear is sufficient.
GBM_BO_USE_SCANOUT is added in case GBM_BO_USE_LINEAR isn't sufficient
on untested hardware.
Fixes#1323
Removed wlr_drm_plane.cursor_bo as it does not serve any purpose
anymore.
Relevant analysis (taken from the PR description):
While trying to implement a fix for #1323, I found that when exporting
the rendered surface into a DMA-BUF and reimporting it with
`GBM_BO_USE_CURSOR`, the resulting object does not appear to be valid.
After some digging (turning on drm-kms debugging and switching to legacy
mode), I managed to extract the following error: ```
[drm:__setplane_check.isra.1 [drm]] Invalid pixel format AR24
little-endian (0x34325241), modifier 0x100000000000001 ``` The format
itself refers to ARGB8888 which is the same format as
`renderer->gbm_format` used in master to create the cursor bo. However,
using `gbm_bo_create` with `GBM_BO_USE_CURSOR` results in a modifier of
0. A modifier of zero represents a linear buffer while the modifier of
the surface that is rendered to is `I915_FORMAT_MOD_X_TILED` (see
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/include/uapi/drm/drm_fourcc.h?h=v4.20.6#n263).
In order to fix this mismatch in modifier, I added the
`GBM_BO_USE_LINEAR` to the render surface and everything started to work
just fine. I wondered however, whether the export and import is really
necessary. I then decided to test if the back buffer of the render
surface works as well, and at least on my hardware (Intel HD 530 and
Intel UHD 620) it does. This is the patch in this PR and this requires
no exporting and importing.
I have to note that I cheated in order to import DMA_BUFs into a cursor
bo when doing the first tests, since on import the Intel drivers check
that the cursor is 64x64. This is strange since cursor sizes other than
64x64 have been around for quite some time now
(https://lists.freedesktop.org/archives/mesa-commit/2014-June/050268.html).
Removing this check made everything work fine. I later (while writing
this PR) found out that `__DRI_IMAGE_USE_CURSOR` (to which
`GBM_BO_USE_CURSOR` translates) has been deprecated in mesa
(https://gitlab.freedesktop.org/mesa/mesa/blob/master/include/GL/internal/dri_interface.h#L1296),
which makes me wonder what the usecase of `GBM_BO_USE_CURSOR` is. The
reason we never encountered this is that when specifying
`GBM_BO_USE_WRITE`, a dumb buffer is created trough DRM and the usage
flag never reaches the Intel driver directly. The relevant code is in
https://gitlab.freedesktop.org/mesa/mesa/blob/master/src/gbm/backends/dri/gbm_dri.c#L1011-1089
. From this it seems that as long as the size, format and modifiers are
right, any surface can be used as a cursor.
We create the EGL config with GBM_FORMAT_ARGB8888, but then initialize GBM BOs
with GBM_FORMAT_XRGB8888. This mismatch confuses Mesa.
Instead, we can always use GBM_FORMAT_ARGB8888, and use DRM_FORMAT_XRGB8888
when calling drmModeAddFB2.
Fixes https://github.com/swaywm/wlroots/issues/1438
Frame events group logically connected pointer events. It makes sense to make
the backend responsible for sending frame events, since once the events are
split (ie. once the frame events are stripped) it's not easy to figure out
which events belongs to which frame again.
This is also how Weston handles frame events.
Fixes https://github.com/swaywm/wlroots/issues/1468
This makes compositors able to block and/or customize set_selection requests
coming from clients. For instance, it's possible for a compositor to disable
rich selection content (by removing all MIME types except text/plain). This
commit implements the design proposed in [1].
Two new events are added to wlr_seat: request_set_selection and
request_set_primary_selection. Compositors need to listen to these events and
either destroy the source or effectively set the selection.
Fixes https://github.com/swaywm/wlroots/issues/1138
[1]: https://github.com/swaywm/wlroots/issues/1367#issuecomment-442403454
The noop backend is similar to headless, but it doesn't contain a
renderer. It can be used as a place to stash views for when there's no
physical outputs connected.
In particular, modified public creator and destructor function names,
added a display destroy listener, safely extract user data from
resources, send correct time (in usecs) in rootston, etc.
This is a common interface that can be used for all primary selection
protocols, as discussed in [1]. A new function wlr_seat_set_primary_selection
is added to set the primary selection for all protocols.
The seat now owns again the source, and resets the selection to NULL when
destroyed.
[1]: https://github.com/swaywm/wlroots/issues/1367#issuecomment-442403454
This commits completely refactors wlr_gtk_primary_selection. The goal is to
remove gtk-primary-selection state from the seat and better handle inert
resources where it makes sense.
wlr_seat_client.primary_selection_devices has been removed and replaced by
wlr_gtk_primary_selection_device. This allows us to make offers inert when the
current selection is replaced.
wlr_seat_set_primary_selection has been removed because it relied on wlr_seat
instead of wlr_gtk_primary_selection_device_manager. A new function,
wlr_gtk_primary_selection_device_manager_set_selection (candidate for the
longest function name in wlroots) has been added. It doesn't take a serial
anymore as serial checking only makes sense for set_selection requests coming
from Wayland clients (serial checking is now done in the Wayland interface
implementation).
Since wlr_gtk_primary_selection_device_manager is now required to set the
selection, a new function wlr_xwayland_set_gtk_primary_selection_device_manager
(candidate number two for longest function name) has been added.
Devices are now made inert when the seat goes away.
Future work includes removing the last primary selection bits from the seat,
mainly wlr_seat.primary_selection_source and wlr_seat.events.primary_selection,
replacing those with new fields in wlr_gtk_primary_selection_device. Or maybe
we could keep those in the seat and replace them with a re-usable interface
(for future zwp_primary_selection_v1 support). We need to think how we'll sync
these three protocols (GTK, X11 and wayland-protocols).
See https://github.com/swaywm/wlroots/issues/1388
wlr_subsurface_from_wlr_surface can return NULL if the wl_surface is still
alive and if the wl_subsurface has been destroyed. Make sure we check for NULL.
Fixes https://github.com/swaywm/sway/issues/3195
This commit makes it possible for a single client to have multiple data devices
for the same seat. This fixes issues with Firefox.
This mainly removes wlr_data_source.offer. We make sure we create one data
offer per device. We now make the offer inert when the source is destroyed.
Fixes the second half of https://github.com/swaywm/wlroots/issues/1041
The read format is dependent on the output, so we first need to make it
current. This fixes a race condition in wlr-screencopy-v1 where a dmabuf
client would cause EGL_NO_SURFACE to be bound at the time when
screencopy needs to query for the preferred format, causing GL errors.
When a client was creating multiple data devices for the same seat, we were
only creating one resource. This is a protocol error.
Instead, create one offer per data device.
This commit also makes offers inert when their source is destroyed.
Fixes part of https://github.com/swaywm/wlroots/issues/1041
Supersedes https://github.com/swaywm/wlroots/pull/1113
The renderer redesign is going to need the render fd before the backend
is fully started, so we have to move the wl registry code to when the
backend is created instead of when it is started.
We also need to stash the wl_keyboard and emit it to library users
later, once they've added their listeners and started the backend.
We were assuming GL_BGRA_EXT was always supported.
We now check that it's supported for rendering. We fail if it isn't because
this format is specified as "always supported" by the Wayland protocol.
We also check if it's supported for reading pixels. A new preferred_read_format
function returns the preferred format that can be used to read pixels. This is
used by the screencopy protocol.
There was a missing copy_drm_surface_mgpu call in drm_connector_schedule_frame
so we asked for a pageflip with an unknown BO, resulting in ENOENT.
Additionally, this commit makes schedule_frame return a bool indicating
failures. This allows schedule_frame_handle_idle_timer to only set
frame_pending to true if a frame has been successfully scheduled. Thus, if a
pageflip fails, rendering won't be blocked forever anymore.
In case a pageflip is already pending, true is returned because a frame has
already been scheduled and will be sent sometime soon.
shm_open is a POSIX function creating an in-memory file. Using it simplifies
the code and removes the dependency on XDG_RUNTIME_DIR. The only downside is
that we need to generate a random name for the shm file.
If a client uses an older version of the dmabuf protocol, use the
`formats` event instead of `modifiers` (since that didn't exist in older
versions).
With a bit of necessary guessing, support dmabuf importing even when
EGL_EXT_image_dma_buf_import_modifiers isn't present instead of
failing up front.
The compositor acts as a relay between applications using the text-input protocol and input methods using the input-method protocol.
This change implements the basic but useful support for input-method, leaving out grabs as well as popups.
Since the source doesn't always come from a client, this field
doesn't make sense. It is replaced by a new "finalized" field in
wlr_client_data_source. This is used to make sure set_actions is
not sent after start_drag has been sent.
A check in data_offer_choose_action has been removed: if an offer
has been sent then start_drag has been called, no need to check.
I also wanted to add a check for wl_data_source.offer, but it
turns out (1) this isn't in the spec (2) it breaks GTK+.
This is some preliminary work for Firefox on Wayland compatibility.
This desynchronizes our rendering loop with the vblank cycle.
In case a compositor doesn't swap buffers but schedules a frame,
emitting a frame event immediately enters a busy-loop.
Instead, ask the backend to send a frame when appropriate. On
Wayland we can just register a frame callback on our surface. On
DRM we can do a no-op pageflip.
Fixes#617Fixesswaywm/sway#2748
This calculates and returns the effective damage of the surface in
surface coordinates, including the client damage (in buffer
coordinates), and damage induced by resize or move events.
When a pageflip is pending, we'll get a DRM event for the connector
in the future. We don't want to free the connector immediately
otherwise we'll use-after-free in the pageflip handler.
This commit adds a new state, "DISAPPEARED". This asks the pageflip
handler to destroy the output after it's done pageflipping.
Originally I asumed tilt_x and tilt_y are very unlikely to change
independent, I was proven wrong.
And while investigating Krita not using the Erasor tool, I found a bug,
which is unrelated though.
* Rename the constraint_create signal to new_constraint for
consistency
* Move the constraint_destroy signal to the constraint itself
* Use rotate_child_position instead of duplicating logic
* Fix inert constraint resource handling
* Style fixes
Sessions can now be retrieved from a backend in a more general manner.
Multi-backend gets back its `session` field that contains the session
if one was created, removing the interfacing from multi backend with the
drm backend directly. This adds the possibility to use sessions even
without the drm backend.
It additionally fixes the bug that 2 session objects got created when
WLR_BACKENDS were set to "libinput,drm".
To allow vt switching without drm backend (and drm fd) on logind, start
listening to PropertiesChanged signals from dbus and parse the session
"Active" property when no master fd was created (this does not change
current drm backend behaviour in any way).
To prevent wl_keyboard keymap being written to by clients, use a unique
file descriptor for each wl_keyboard resource.
Reference: weston, commit 76829fc4eaea329d2a525c3978271e13bd76c078
This commit allows outputs that need a CRTC to steal it from
user-disabled outputs. Note that in the case there are enough
CRTCs, disabled outputs don't loose it (so there's no modeset
and plane initialization needed after DPMS). CRTC allocation
still prefers to keep the old configuration, even if that means
allocating an extra CRTC to a disabled output.
CRTC reallocation now happen when enabling/disabling an output as
well as when trying to modeset. When enabling an output without a
CRTC, we realloc to try to steal a CRTC from a disabled output
(that doesn't really need the CRTC). When disabling an output, we
try to give our CRTC to an output that needs one. Modesetting is
similar to enabling.
A new DRM connector field has been added: `desired_enabled`.
Outputs without CRTCs get automatically disabled. This field keeps
track of the state desired by the user, allowing to automatically
re-enable outputs when a CRTC becomes free.
This required some changes to the allocation algorithm. Previously,
the algorithm tried to keep the previous configuration even if a
new configuration with a better score was possible (it only changed
configuration when the old one didn't work anymore). This is now
changed and the old configuration (still preferred) is only
retained without considering new possibilities when it's perfect
(all outputs have CRTCs).
User-disabled outputs now have `possible_crtcs` set to 0, meaning
they can only retain a previous CRTC (not acquire a new one). The
allocation algorithm has been updated to do not bump the score
when assigning a CRTC to a disabled output.
sx, sy used to store the buffer offset of the drag surface which was
then be added (by rootston) to the drag icon position.
Buffer offsets are handled already in surface_intersect_output
(output.c) so they were added twice for dnd surfaces.
This commit handles better situations in which the number of
connected outputs is greater than the number of available CRTCs.
It'll enable as many outputs as possible, and transfer CRTCs to
outputs that need one on unplug.
This changes CRTC and plane reallocation to happen after scanning
DRM connectors instead of on modeset.
This cleanups CRTCs and planes on unplug to allow them to be
re-used for other outputs.
On modeset, if an output doesn't have a CRTC, the desired mode is
saved and used later when the output gains a CRTC.
Future work includes giving priority to enabled outputs over
disabled ones for CRTC allocation. This requires the compositor to
know about all outputs (even outputs without CRTCs) to properly
modeset outputs enabled in the compositor config file and disable
outputs disabled in the config file.
This is so we can potentially add comments to it, and so if a user looks
at the installed header, they can see the /* #undef WLR_HAS_FEATURE */
line to see every option, even if not available.
Implement the tablet-v2 tablet tool's implicit grab semantics for
buttons and tip.
This avoids losing focus (to other [sub]surfaces) when a button is held,
or the tip is down.
This should help when the device is used close to a surface's border and
would otherwise have to be very precise.
This introduces -DWLR_USE_UNSTABLE and adds information regarding the
stability status to all headers. I started with a conservative set of
headers to mark as stable:
- types/wlr_matrix.h
- util/edges.h
- util/log.h
- util/region.h
- xcursor.h
Whenever a new surface is created, we have to update the cursor focus,
even if there's no input event. So, we generate one motion event, and
reuse the code to update the proper cursor focus. We need to do this
for all surface roles - toplevels, popups, subsurfaces.
Fixes#1162
153f37bdf5 (#1145) removed the
wlr_xwayland_is_unamanged function while fixing OR, because it was
belieived that it's supposed to work around the broken OR handling.
This was a misunderstanding. is_unmanaged is (while sort of a hack)
intended to work around inherent differences between "real" X sessions
and our Xwayland/wayland situation.
The main reason it exists is to support applications like rofi and dzen,
while not handing focus to other OR windows (which should *not* be
required).
Traditionally, these applications just grabbed input from X and didn't
need to be focused by any logic in the WM. Which of course doesn't work
in wayland compositors. So we have to give them focus in some way.
Giving *every* OR window focus, breaks other applications that don't
expect focus to change.
A testcase that was pointed out to me where wlr_xwayland_is_unamanged was
breaking things is https://github.com/swaywm/sway/issues/2128 (syncplay,
gitk, gitgui)
Supposedly it broke using keyboard to navigate the menus.
I can't reproduce this with this patch. The popups can be navigated as
long as the parent has focus.
Implement the basic logic for tablet-v2 tablet_pad's grabs. And plug in
the default grab.
Features like "holding" the focus should be implemented via grabs, like
they are for pointer and keyboard.
The override_redirect flag can change on configure notify and
on map notify. This adds an event to know when it changes.
This removes wlr_xwayland_surface_is_unmanaged which was wrongly
using the window type to decide whether the view should be
unmanaged.
A similar patch was proposed to Weston, but has never been
merged upstream [1].
[1]: https://patchwork.freedesktop.org/patch/211161/
There were a few issues after rebase, that the merge algorithm didn't
throw at my face:
wlr_output did a check on the actual role, not a string anymore, so that
had to go to allow tablet-v2 to set cursor surfaces.
A few L_DEBUG/L_ERRORs were still around
There was a user-after-free in tablet-group free()ing, probably after
insufficient testing from a previous feedback pass
The previous naming was based on the input-device capability names from
libinput.
With code that uses the libinput_tablet_tool and mapping into tablet-v2,
this is confusing, so the name is changed to follow the names used in
the protocol.
This adds the management code to manage tablet tools lifetimes from
libinput.
It follows the suggestion made in the tablet-unstable-v2.xml to destroy
tablet_tools once all tablets that it got into contact with were removed
from the system. This is implemented via a refcount.
If a tool is *not* unique, it will be destroyed on proximity out. This
is libinput specific and mentioned in libinput docs that tools will not
be found again, so we shouldn't keep a reference to them.
Also they can't be on other tablets as well, because they cannot be
tracked.
The naming in this commit is a bit off (to not break things).
The wlr names stay the same, tablet_tool is the libinput_device with
capaiblity LIBINPUT_DEVICE_CAP_TABLET_TOOL which is more akin to
"tablet" in the tablet-unstable-v2 protocol.
The struct that corresponds to the tablet_tool in tablet-unstable-v2 is
called tablet_tool_tool, a rename should be done at some point in the
future.
To begin with, no-op updates are unnecessary, so this patch is an
improvement on its own.
Then, this fixes hotplugging issues with xwayland. xwayland waits
for both wl_output and xdg_output to send a "done" event. However,
it doesn't handle well desynchronized "done" updates: if xdg-output
sends "done" twice, the second one will wait for the next wl_output
"done" event. This is an issue when the first is a no-op and the
second is a real update: the second isn't applied. I've considered
patching xwayland instead, but it seems pretty complicated.
It is common to want to iterate an xdg-surface's popups separately from
the toplevel and subsurfaces. For example, popups are typically rendered
on top of most other surfaces.
wlr_xdg_surface_for_each_surface continues to iterate both surfaces and
popups to maintain backwards compatibility.