Wrong monitor positions reported on latest GTK3 release

[JakeStanger]

Sway Version: Git (dcdb727)
Wlroots Version: Git (325d84381)

Description:

The latest GTK 3.24 release (3.24.42) includes a fix described as "Fix monitor sizes".

https://gitlab.gnome.org/GNOME/gtk/-/commit/51b04c5007f89142ed5a1ab240c03d5800b86b3d

This seems to have inadvertently caused some issues on wlroots-based compositors, whereby the gdk_monitor_get_geometry function now returns 0, 0 for the position of every monitor.

This issue did not occur prior to the GTK update.

I have tested it on the following:

• Gnome 46.1
• KDE Plasma 6.0.4
• Sway (latest Git)
• Hyprland 0.40.0

On Gnome/KDE the positions are reported correctly, however the bug occurs on both Sway and Hyprland. I suspect this therefore may be wlroots related, but have opened the issue here first as per the wlroots repo instructions.

A basic reproduction can be seen with the following Python 3 script:

import gi
gi.require_version('Gdk', '3.0')
from gi.repository import Gdk


display = Gdk.Display.get_default()

def print_geometry(num):
    mon = display.get_monitor(num).get_geometry()
    print(mon.x, mon.y, mon.width, mon.height)

# add/remove entries according to the number of monitors (I have 3)
print_geometry(0)
print_geometry(1)
print_geometry(2)

Results in:

# incorrect
λ python gtk-test.py
0 0 2560 1440
0 0 1920 1080
0 0 2560 1440

In my case I have 3 horizontally aligned monitors, so I would expect the X positions to be offset by their widths according to their alignment:

# correct
λ python gtk-test.py
1080 0 2560 1440
0 0 1920 1080
2520 0 2560 1440

The effect of this is that the gdk_display_get_monitor_at_point function now returns the 1st monitor always.

If you need any more info, let me know.

[emersion]

wlroots sends 0,0 as the position via wl_output, because regular applications shouldn't care about the output layout and and wl_output doesn't expose enough information anyways. wlroots does send the correct position via xdg_output though. I suspect GTK doesn't wait for the done event when the monitor geometry is queried, and falls back to the wl_output partial data as a result?

Sounds like a GTK bug.

Can you run your demo with WAYLAND_DEBUG=client and post the logs?

[JakeStanger]

I suspect GTK doesn't wait for the done event when the monitor geometry is queried, and falls back to the wl_output partial data as a result?

The weird thing is the GTK commit seems to suggest the opposite?

The logs do seem to back up your theory though, I think. You can see zxdg_output_v1 is reporting the correct positions while wl_output just returns 0,0.

✦ λ WAYLAND_DEBUG=client python gtk-test.py 
[1891687.525]  -> wl_display@1.get_registry(new id wl_registry@2)
[1891687.538]  -> wl_display@1.sync(new id wl_callback@3)
[1891687.614] wl_display@1.delete_id(3)
[1891687.621] wl_registry@2.global(1, "wp_tearing_control_manager_v1", 1)
[1891687.627] wl_registry@2.global(2, "wp_fractional_scale_manager_v1", 1)
[1891687.634] wl_registry@2.global(3, "zxdg_output_manager_v1", 3)
[1891687.637]  -> wl_registry@2.bind(3, "zxdg_output_manager_v1", 3, new id [unknown]@4)
[1891687.641]  -> wl_display@1.sync(new id wl_callback@5)
[1891687.645] wl_registry@2.global(4, "wp_cursor_shape_manager_v1", 1)
[1891687.648] wl_registry@2.global(5, "zwp_idle_inhibit_manager_v1", 1)
[1891687.652] wl_registry@2.global(6, "zwp_relative_pointer_manager_v1", 1)
[1891687.657] wl_registry@2.global(7, "zxdg_decoration_manager_v1", 1)
[1891687.661] wl_registry@2.global(8, "wp_alpha_modifier_v1", 1)
[1891687.665] wl_registry@2.global(9, "zwlr_gamma_control_manager_v1", 1)
[1891687.668] wl_registry@2.global(10, "ext_foreign_toplevel_list_v1", 1)
[1891687.671] wl_registry@2.global(11, "zwp_pointer_gestures_v1", 3)
[1891687.675]  -> wl_registry@2.bind(11, "zwp_pointer_gestures_v1", 1, new id [unknown]@6)
[1891687.678] wl_registry@2.global(12, "zwlr_foreign_toplevel_manager_v1", 3)
[1891687.682] wl_registry@2.global(13, "zwp_keyboard_shortcuts_inhibit_manager_v1", 1)
[1891687.686]  -> wl_registry@2.bind(13, "zwp_keyboard_shortcuts_inhibit_manager_v1", 1, new id [unknown]@7)
[1891687.690] wl_registry@2.global(14, "zwp_text_input_manager_v3", 1)
[1891687.694] wl_registry@2.global(15, "zwp_pointer_constraints_v1", 1)
[1891687.698] wl_registry@2.global(16, "zwlr_output_power_manager_v1", 1)
[1891687.703] wl_registry@2.global(17, "xdg_activation_v1", 1)
[1891687.706]  -> wl_registry@2.bind(17, "xdg_activation_v1", 1, new id [unknown]@8)
[1891687.710] wl_registry@2.global(18, "ext_idle_notifier_v1", 1)
[1891687.714] wl_registry@2.global(19, "ext_session_lock_manager_v1", 1)
[1891687.718] wl_registry@2.global(20, "zwp_input_method_manager_v2", 1)
[1891687.721] wl_registry@2.global(21, "zwp_virtual_keyboard_manager_v1", 1)
[1891687.725] wl_registry@2.global(22, "zwlr_virtual_pointer_manager_v1", 2)
[1891687.729] wl_registry@2.global(23, "zwlr_output_manager_v1", 4)
[1891687.732] wl_registry@2.global(24, "hyprland_toplevel_export_manager_v1", 2)
[1891687.736] wl_registry@2.global(25, "zwp_text_input_manager_v1", 1)
[1891687.740] wl_registry@2.global(26, "hyprland_global_shortcuts_manager_v1", 1)
[1891687.744] wl_registry@2.global(27, "zwlr_screencopy_manager_v1", 3)
[1891687.748] wl_registry@2.global(28, "wl_shm", 1)
[1891687.751]  -> wl_registry@2.bind(28, "wl_shm", 1, new id [unknown]@9)
[1891687.755] wl_registry@2.global(29, "wl_drm", 2)
[1891687.758] wl_registry@2.global(30, "zwp_linux_dmabuf_v1", 4)
[1891687.763] wl_registry@2.global(31, "wl_compositor", 6)
[1891687.766]  -> wl_registry@2.bind(31, "wl_compositor", 3, new id [unknown]@10)
[1891687.771] wl_registry@2.global(32, "wl_subcompositor", 1)
[1891687.774]  -> wl_registry@2.bind(32, "wl_subcompositor", 1, new id [unknown]@11)
[1891687.777] wl_registry@2.global(33, "wl_data_device_manager", 3)
[1891687.780]  -> wl_registry@2.bind(33, "wl_data_device_manager", 3, new id [unknown]@12)
[1891687.783] wl_registry@2.global(34, "zwlr_export_dmabuf_manager_v1", 1)
[1891687.787] wl_registry@2.global(35, "zwlr_data_control_manager_v1", 2)
[1891687.792] wl_registry@2.global(36, "zwp_primary_selection_device_manager_v1", 1)
[1891687.796]  -> wl_registry@2.bind(36, "zwp_primary_selection_device_manager_v1", 1, new id [unknown]@13)
[1891687.800] wl_registry@2.global(37, "wp_viewporter", 1)
[1891687.804] wl_registry@2.global(38, "xdg_wm_base", 6)
[1891687.806] wl_registry@2.global(39, "wl_seat", 9)
[1891687.809] wl_registry@2.global(40, "wp_presentation", 1)
[1891687.812] wl_registry@2.global(41, "zwlr_layer_shell_v1", 4)
[1891687.815] wl_registry@2.global(42, "org_kde_kwin_server_decoration_manager", 1)
[1891687.818]  -> wl_registry@2.bind(42, "org_kde_kwin_server_decoration_manager", 1, new id [unknown]@14)
[1891687.827] wl_registry@2.global(43, "wp_drm_lease_device_v1", 1)
[1891687.831] wl_registry@2.global(44, "zwp_tablet_manager_v2", 1)
[1891687.834]  -> wl_registry@2.bind(44, "zwp_tablet_manager_v2", 1, new id [unknown]@15)
[1891687.837] wl_registry@2.global(45, "zxdg_exporter_v1", 1)
[1891687.841]  -> wl_registry@2.bind(45, "zxdg_exporter_v1", 1, new id [unknown]@16)
[1891687.844] wl_registry@2.global(46, "zxdg_importer_v1", 1)
[1891687.848]  -> wl_registry@2.bind(46, "zxdg_importer_v1", 1, new id [unknown]@17)
[1891687.852] wl_registry@2.global(47, "zxdg_exporter_v2", 1)
[1891687.856] wl_registry@2.global(48, "zxdg_importer_v2", 1)
[1891687.860] wl_registry@2.global(49, "wp_single_pixel_buffer_manager_v1", 1)
[1891687.863] wl_registry@2.global(50, "xwayland_shell_v1", 1)
[1891687.866] wl_registry@2.global(51, "wl_output", 4)
[1891687.871]  -> wl_registry@2.bind(51, "wl_output", 2, new id [unknown]@18)
[1891687.897]  -> zxdg_output_manager_v1@4.get_xdg_output(new id zxdg_output_v1@19, wl_output@18)
[1891687.901]  -> wl_display@1.sync(new id wl_callback@20)
[1891687.905] wl_registry@2.global(52, "wl_output", 4)
[1891687.908]  -> wl_registry@2.bind(52, "wl_output", 2, new id [unknown]@21)
[1891687.913]  -> zxdg_output_manager_v1@4.get_xdg_output(new id zxdg_output_v1@22, wl_output@21)
[1891687.917]  -> wl_display@1.sync(new id wl_callback@23)
[1891687.921] wl_registry@2.global(53, "wl_output", 4)
[1891687.924]  -> wl_registry@2.bind(53, "wl_output", 2, new id [unknown]@24)
[1891687.929]  -> zxdg_output_manager_v1@4.get_xdg_output(new id zxdg_output_v1@25, wl_output@24)
[1891687.933]  -> wl_display@1.sync(new id wl_callback@26)
[1891687.937] wl_callback@3.done(486)
[1891687.971]  -> wl_shm@9.create_pool(new id wl_shm_pool@3, fd 10, 2304)
[1891688.102]  -> wl_shm_pool@3.resize(6912)
[1891688.156]  -> wl_shm_pool@3.resize(16128)
[1891688.235]  -> wl_shm_pool@3.resize(34560)
[1891688.369]  -> wl_shm_pool@3.resize(71424)
[1891688.630]  -> wl_shm_pool@3.resize(145152)
[1891689.298]  -> wl_shm_pool@3.resize(292608)
[1891690.131]  -> wl_shm_pool@3.resize(587520)
[1891692.996]  -> wl_registry@2.bind(39, "wl_seat", 5, new id [unknown]@27)
[1891694.971]  -> wl_compositor@10.create_surface(new id wl_surface@28)
[1891694.982]  -> zwp_primary_selection_device_manager_v1@13.get_device(new id zwp_primary_selection_device_v1@29, wl_seat@27)
[1891694.987]  -> wl_data_device_manager@12.get_data_device(new id wl_data_device@30, wl_seat@27)
[1891695.030]  -> wl_compositor@10.create_surface(new id wl_surface@31)
[1891695.034]  -> zwp_tablet_manager_v2@15.get_tablet_seat(new id zwp_tablet_seat_v2@32, wl_seat@27)
[1891695.040]  -> wl_display@1.sync(new id wl_callback@33)
[1891695.164] wl_display@1.delete_id(5)
[1891695.168] wl_display@1.delete_id(20)
[1891695.171] wl_display@1.delete_id(23)
[1891695.174] wl_display@1.delete_id(26)
[1891695.176] wl_display@1.delete_id(33)
[1891695.179] wl_callback@5.done(486)
[1891695.182] wl_shm@9.format(0)
[1891695.185] wl_shm@9.format(1)
[1891695.187] wl_shm@9.format(875709016)
[1891695.190] wl_shm@9.format(875708993)
[1891695.193] wl_shm@9.format(875710274)
[1891695.196] wl_shm@9.format(842094674)
[1891695.199] wl_shm@9.format(842088786)
[1891695.202] wl_shm@9.format(892426322)
[1891695.205] wl_shm@9.format(892420434)
[1891695.207] wl_shm@9.format(909199186)
[1891695.210] wl_shm@9.format(1211384408)
[1891695.213] wl_shm@9.format(1211384385)
[1891695.216] wl_shm@9.format(942948952)
[1891695.218] wl_shm@9.format(942948929)
[1891695.221] org_kde_kwin_server_decoration_manager@14.default_mode(2)
[1891695.225] wl_output@18.geometry(0, 0, 600, 340, 0, "ASUSTek COMPUTER INC", "PA278QV", 0)
[1891695.232] wl_output@18.mode(1, 2560, 1440, 74924)
[1891695.235] wl_output@18.scale(1)
[1891695.238] wl_output@18.done()
[1891695.250] zxdg_output_v1@19.name("DP-1")
[1891695.253] zxdg_output_v1@19.description("ASUSTek COMPUTER INC PA278QV M4LMQS060475 (DP-1)")
[1891695.256] zxdg_output_v1@19.logical_position(1920, 0)
[1891695.260] zxdg_output_v1@19.logical_size(2560, 1440)
[1891695.263] wl_output@18.done()
[1891695.267] wl_callback@20.done(486)
[1891695.270] wl_output@21.geometry(0, 0, 600, 340, 0, "AOC", "27V2G5", 0)
[1891695.276] wl_output@21.mode(1, 1920, 1080, 74973)
[1891695.279] wl_output@21.scale(1)
[1891695.282] wl_output@21.done()
[1891695.287] zxdg_output_v1@22.name("DP-2")
[1891695.290] zxdg_output_v1@22.description("AOC 27V2G5 0x00000E39 (DP-2)")
[1891695.293] zxdg_output_v1@22.logical_position(0, 360)
[1891695.296] zxdg_output_v1@22.logical_size(1920, 1080)
[1891695.299] wl_output@21.done()
[1891695.303] wl_callback@23.done(486)
[1891695.306] wl_output@24.geometry(0, 0, 600, 340, 0, "AOC", "Q27P2W", 0)
[1891695.311] wl_output@24.mode(1, 2560, 1440, 74968)
[1891695.315] wl_output@24.scale(1)
[1891695.318] wl_output@24.done()
[1891695.322] zxdg_output_v1@25.name("DP-3")
[1891695.325] zxdg_output_v1@25.description("AOC Q27P2W ASEP69A000495 (DP-3)")
[1891695.328] zxdg_output_v1@25.logical_position(4480, 0)
[1891695.332] zxdg_output_v1@25.logical_size(2560, 1440)
[1891695.335] wl_output@24.done()
[1891695.339] wl_callback@26.done(486)
[1891695.342] wl_seat@27.name("seat0")
[1891695.345] wl_seat@27.capabilities(3)
[1891695.349]  -> wl_seat@27.get_pointer(new id wl_pointer@26)
[1891695.356]  -> zwp_pointer_gestures_v1@6.get_swipe_gesture(new id zwp_pointer_gesture_swipe_v1@23, wl_pointer@26)
[1891695.359]  -> zwp_pointer_gestures_v1@6.get_pinch_gesture(new id zwp_pointer_gesture_pinch_v1@20, wl_pointer@26)
[1891695.363]  -> wl_seat@27.get_keyboard(new id wl_keyboard@5)
[1891695.368] wl_callback@33.done(486)
[1891695.371]  -> wl_registry@2.bind(38, "xdg_wm_base", 6, new id [unknown]@33)
0 0 2560 1440
0 0 1920 1080
0 0 2560 1440