Since output layout is destroyed when the wayland display is destroyed
we run into a destroy listener order problem: Either the display starts
destroying the outputs first, in which case we're good: The existing
handling will clean up. However, things go wrong if the display decides
to destroy the output layout first. In this case, sway will hold
invalid references to the output layout as part of each output so that
when it finally goes to destroy them, sway will dereference destroyed
output layout bits.
Ref: https://github.com/swaywm/sway/pull/6844#issuecomment-1843599513
With recent wlroots changes, backends which don't support output
modes can now support being disabled.
We were always marking mode-less outputs as disabled. Stop doing
that, check whether the output takes up some space in the layout
instead.
In case a display is unplugged, the sway output may be removed from the
userdata before the gamma_control can be reset. In this case we can't
schedule a commit on the output, simply return within the function.
backtrace full:
#0 handle_gamma_control_set_gamma (listener=0x4856a8 <server+616>, data=0x7ffce1ed59c0) at ../sway/desktop/output.c:1105
server = 0x485440 <server>
event = 0x7ffce1ed59c0
output = 0x0
#1 0x00007f430d1dca0c in wl_signal_emit_mutable ()
from /nix/store/ky1g6ylzr2m4bq8fy0gzrnqmjr6948k5-wayland-1.22.0/lib/libwayland-server.so.0
No symbol table info available.
#2 0x00007f430d142370 in gamma_control_destroy (gamma_control=0x29eb9b0) at ../types/wlr_gamma_control_v1.c:37
manager = 0x27e33e0
output = 0x2a10770
event = {output = 0x2a10770, control = 0x0}
#3 0x00007f430d14239b in gamma_control_handle_output_destroy (listener=<optimized out>, data=<optimized out>)
at ../types/wlr_gamma_control_v1.c:59
gamma_control = <optimized out>
#4 0x00007f430d1dca0c in wl_signal_emit_mutable ()
from /nix/store/ky1g6ylzr2m4bq8fy0gzrnqmjr6948k5-wayland-1.22.0/lib/libwayland-server.so.0
No symbol table info available.
#5 0x00007f430d12a0e0 in wlr_output_destroy (output=output@entry=0x2a10770) at ../types/output/output.c:384
cursor = <optimized out>
tmp_cursor = <optimized out>
layer = <optimized out>
tmp_layer = <optimized out>
#6 0x00007f430d114ecf in disconnect_drm_connector (conn=conn@entry=0x2a10770) at ../backend/drm/drm.c:1757
__PRETTY_FUNCTION__ = "disconnect_drm_connector"
#7 0x00007f430d117078 in scan_drm_connectors (drm=drm@entry=0x1eebab0, event=event@entry=0x7ffce1ed5c1c) at ../backend/drm/drm.c:1597
c = <optimized out>
wlr_conn = 0x2a10770
drm_conn = 0x2e760d0
conn_id = <optimized out>
index = 4
i = 4
res = 0x2e761f0
seen_len = 5
seen = {true, true, true, true, true, false}
new_outputs_len = 0
new_outputs = 0x7ffce1ed5ab0
conn = <optimized out>
tmp_conn = <optimized out>
index = <optimized out>
#8 0x00007f430d113425 in handle_dev_change (listener=0x1eebbb0, data=0x7ffce1ed5c18) at ../backend/drm/backend.c:157
drm = 0x1eebab0
change = 0x7ffce1ed5c18
#9 0x00007f430d1dca0c in wl_signal_emit_mutable ()
from /nix/store/ky1g6ylzr2m4bq8fy0gzrnqmjr6948k5-wayland-1.22.0/lib/libwayland-server.so.0
No symbol table info available.
#10 0x00007f430d111696 in handle_udev_event (fd=<optimized out>, mask=<optimized out>, data=<optimized out>)
at ../backend/session/session.c:213
event = {type = WLR_DEVICE_HOTPLUG, {hotplug = {connector_id = 0, prop_id = 0}}}
devnum = <optimized out>
dev = 0x1ed9460
session = <optimized out>
udev_dev = 0x2e70db0
sysname = 0x2e73c60 "card0"
devnode = <optimized out>
action = 0x7f430d6677b5 "change"
seat = <optimized out>
__PRETTY_FUNCTION__ = "handle_udev_event"
#11 0x00007f430d1de8e2 in wl_event_loop_dispatch ()
from /nix/store/ky1g6ylzr2m4bq8fy0gzrnqmjr6948k5-wayland-1.22.0/lib/libwayland-server.so.0
No symbol table info available.
#12 0x00007f430d1dc445 in wl_display_run () from /nix/store/ky1g6ylzr2m4bq8fy0gzrnqmjr6948k5-wayland-1.22.0/lib/libwayland-server.so.0
No symbol table info available.
#13 0x000000000041daa5 in server_run (server=server@entry=0x485440 <server>) at ../sway/server.c:338
No locals.
#14 0x000000000041cf4d in main (argc=<optimized out>, argv=0x7ffce1ed5fe8) at ../sway/main.c:415
verbose = false
debug = false
validate = false
allow_unsupported_gpu = false
config_path = 0x0
c = <optimized out>
where event->output->data is NULL:
(gdb) p event->output->data
$5 = (void *) 0x0
Check whether output->damage_ring.current is empty before calling
wlr_output_attach_render(). Saves us from having to un-do that
via wlr_output_rollback().
fixes#7394
Test cases:
* zwlr_output_configuration_head_v1_set_adaptive_sync 0->0, no change
* 0->1, enabled
* 1->0, disabled
* 1->1, no change
Similar tests with an incapable display resulted in `"Adaptive sync
failed, ignoring"` messages as expected.
