We were crashing in the error codepath [1] when
wlr_drm_create_lease() fails.
To fix this, delay the creation of the wlr_drm_lease_v1 until the
request is granted. Previously we were allocating that struct early
without populating the drm_lease field. However that means we ended
up with a half-constructed struct in the error codepath which is
annoying to handle.
[1]: https://github.com/swaywm/sway/issues/7204#issuecomment-1269797356
On first commit, require a new buffer if the compositor called a
mode-setting function, even if the mode won't change. This makes it
so the swapchain is created now.
Stop trying to check whether the backend supports buffer-less modesets
because that makes everything more complicated. For instance, the
DRM backend doesn't need a new buffer if the previous DRM master left
the output enabled.
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3499
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3502
Some compositors want to have full control over the buffers attached
to the output, and don't want to use the internal swapchain. Such
compositors include KWinFT (allocates its buffers on its own) and
gamescope (uses a headless output without any buffers).
Let's just make output_ensure_buffer() a no-op in that case.
When starting up, the compositor might call wlr_output_set_mode()
with a mode which is already the current one. wlroots will detect
this and make the wlr_output_set_mode() call a no-op. During the
next wlr_output_commit() call, wlroots will perform an atomic
commit without the ALLOW_MODESET flag.
This is an issue, because some drivers need ALLOW_MODESET even if
the mode is the same. For instance, if the FB stride or modifier
changed, some drivers require a modeset.
Add a new flag "allow_artifacts" which is set when the compositor
calls mode-setting functions. Use this flag to figure out whether
we want to perform atomic commits with ALLOW_MODESET.
(The name "allow_artifacts" is picked because ALLOW_MODESET is a
misnomer, see [1].)
[1]: https://patchwork.freedesktop.org/patch/505107/
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3499
Instead of using low-level wl_shm_buffer and wlr_dmabuf_v1_buffer
APIs, use the unified wlr_buffer APIs. That way it doesn't matter
what the exact wlr_buffer implementation is used, any which provides
the necessary capabilities (data_ptr or dmabuf) would work.
Simplifies the logic a bit, and will make the transition to wlr_shm
easier.
There doesn't appear to be any good reason to warp the cursor to
the top-left corner when all outputs are disconnected; it's no more
valid than any other (x,y) point in that case.
The real-world case here is a user with a single external monitor
turning it off (which apparently counts as disconnected depending
on the connection type/hardware). For that user, it's desirable to
have the cursor remain in its original location when the monitor
is turned back on.
It should be considered a bug if a compositor sets a non-finite
cursor position, so fail loudly (in debug builds) if that happens.
The existing check in wlr_cursor_warp_closest() is now redundant,
and would silently hide such bugs, so remove it.
In wlr_output_attach_render(), stop setting
wlr_output.pending.buffer. This removes one footgun: using the
wlr_buffer at that stage is invalid, because rendering operations
haven't been flushed to the GPU yet. We need to wait until
output_clear_back_buffer() for the wlr_buffer to be used safely.
Instead, set wlr_output.pending.buffer in wlr_output_test() and
wlr_output_commit().
Additionally, move the output_clear_back_buffer() from
wlr_output_commit_state() to wlr_output_commit(). This reduces the
number of calls in the failure path.
We can just use pending.buffer instead. It's completely fine to
call wlr_swapchain_set_buffer_submitted() with a buffer which
doesn't come from the swapchain, in which case it's a no-op.
This is documented to reset the gamma LUT, but we don't handle this
properly.
While at it, make sure we leave wlr_output.pending in a good state
on allocation failure.
wlr_buffer.c is difficult to read because it contains a mixed bag
of unrelated things: base buffer type, buffer implementations,
buffer resource factory, and client buffer.
Split each of these into their own file.
valgrind said (on exit from labwc):
Invalid write of size 8
at 0x487DEAF: wl_list_remove (wayland-util.c:56)
by 0x487DF80: wl_signal_emit_mutable (wayland-server.c:2182)
by 0x48CD6B7: backend_destroy.part.0.lto_priv.0 (backend.c:41)
by 0x48DC19D: multi_backend_destroy (backend.c:58)
by 0x4880286: UnknownInlinedFun (wayland-server.c:2315)
by 0x4880286: wl_display_destroy (wayland-server.c:1170)
by 0x112491: UnknownInlinedFun (server.c:485)
by 0x112491: main (main.c:110)
Address 0x1f9d0210 is 112 bytes inside a block of size 136 free'd
at 0x484426F: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
by 0x487DF6D: wl_signal_emit_mutable (wayland-server.c:2179)
by 0x48CD6B7: backend_destroy.part.0.lto_priv.0 (backend.c:41)
by 0x48DC19D: multi_backend_destroy (backend.c:58)
by 0x4880286: UnknownInlinedFun (wayland-server.c:2315)
by 0x4880286: wl_display_destroy (wayland-server.c:1170)
by 0x112491: UnknownInlinedFun (server.c:485)
by 0x112491: main (main.c:110)
Block was alloc'd at
at 0x4846A73: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
by 0x4918D4E: drm_lease_device_v1_create (wlr_drm_lease_v1.c:639)
by 0x48D3B00: wlr_multi_for_each_backend (backend.c:249)
by 0x49191D2: wlr_drm_lease_v1_manager_create (wlr_drm_lease_v1.c:706)
by 0x111EE9: UnknownInlinedFun (server.c:384)
by 0x111EE9: main (main.c:92)
dac040f87f mistakenly renamed
xdg_surface_destroy listener, which was listening to *unmap* events, to
xdg_surface_unmap. The actual fix, however, is to listen to destroy
events. This fixes various crashes.
If the first test in output_ensure_buffer() fails with modifiers we
replace the swapchain with a modifierless swapchain and try again.
However if that fails as well the output is currently stuck without
modifiers until the next modeset.
To fix this, destroy the modifierless swapchain if the test using it
fails. The next output_attach_back_buffer() call will create a swapchain
that allows modifiers when needed.
