The open source OpenXR runtime
comp/window_direct_mode: Use XCB/Xlib interop.
Since there currently is no Vulkan extension that takes XCB handles to
aqcuire the display Xlib interop needs to be used.
Before this patch Monado was opening connections for both APIs, which
introduced overhead.
Even though all XCB handles can be casted to Xlib ones, this cannot be
done with the main xcb_connection_t / Display. In it's design the
interop between both APIs can create a xcb_connection_t from a XCB
handle, but not the other way round. So in an interop case the Xlib
connection is the main one, since it's on a higher level.
More information on this can be found here:
https://xcb.freedesktop.org/MixingCalls/
Unfortunately the clean solution for this would be to specify a Vulkan
extension that takes XCB handles. This would make sense since Vulkan
is aware of XCB in other parts of the API as well. In Mesa the Xlib
structs will be ultimately casted to XCB.
+25
-24
+1
-1
CMakeLists.txt
+1
-1
CMakeLists.txt
···
50
50
find_package(udev REQUIRED)
51
51
set(BUILD_DRIVER_V4L2 TRUE)
52
52
if(PKGCONFIG_FOUND)
53
-
pkg_check_modules(XCB xcb xcb-randr)
53
+
pkg_check_modules(XCB xcb xcb-randr x11-xcb)
54
54
55
55
pkg_search_module(WAYLAND wayland-client)
56
56
pkg_search_module(WAYLAND_SCANNER wayland-scanner)
+2
-1
meson.build
+2
-1
meson.build
···
81
81
82
82
# TODO: make these behave well when not present
83
83
x11 = dependency('x11', required: get_option('xlib'))
84
+
x11_xcb = dependency('x11-xcb', required: get_option('xlib'))
84
85
xcb = dependency('xcb', required: get_option('xcb'))
85
86
xcb_randr = dependency('xcb-randr', required: get_option('xcb'))
86
87
···
116
117
build_xcb = xcb.found()
117
118
endif
118
119
119
-
build_xcb_xrandr_direct = build_xcb and build_xlib and xcb_randr.found()
120
+
build_xcb_xrandr_direct = build_xcb and build_xlib and xcb_randr.found() and x11_xcb.found()
120
121
121
122
build_wayland = false
122
123
if get_option('wayland').enabled() or get_option('wayland').auto()
+21
-21
src/xrt/compositor/main/comp_window_direct_mode.cpp
+21
-21
src/xrt/compositor/main/comp_window_direct_mode.cpp
···
10
10
11
11
#include <xcb/xcb.h>
12
12
#include <xcb/randr.h>
13
+
#include <X11/Xlib-xcb.h>
13
14
#include <X11/extensions/Xrandr.h>
14
15
15
16
#include <map>
···
58
59
struct comp_window base = comp_window();
59
60
60
61
Display *dpy = nullptr;
61
-
xcb_connection_t *connection = nullptr;
62
62
xcb_screen_t *screen = nullptr;
63
63
64
64
std::map<uint32_t, xcb_randr_mode_info_t> randr_modes = {};
···
191
191
d->display = VK_NULL_HANDLE;
192
192
}
193
193
194
-
if (w_direct->connection) {
195
-
xcb_disconnect(w_direct->connection);
196
-
w_direct->connection = nullptr;
194
+
if (w_direct->dpy) {
195
+
XCloseDisplay(w_direct->dpy);
196
+
w_direct->dpy = nullptr;
197
197
}
198
198
199
199
delete reinterpret_cast<struct comp_window_direct *>(w);
···
228
228
return false;
229
229
}
230
230
231
+
xcb_connection_t *connection = XGetXCBConnection(w_direct->dpy);
232
+
231
233
xcb_screen_iterator_t iter =
232
-
xcb_setup_roots_iterator(xcb_get_setup(w_direct->connection));
234
+
xcb_setup_roots_iterator(xcb_get_setup(connection));
233
235
234
236
w_direct->screen = iter.data;
235
237
···
676
678
COMP_ERROR(w->base.c, "Could not open X display.");
677
679
return false;
678
680
}
679
-
680
-
//! @todo only open one connection and use XGetXCBConnection.
681
-
w->connection = xcb_connect(nullptr, nullptr);
682
-
return !xcb_connection_has_error(w->connection);
681
+
return true;
683
682
}
684
683
685
684
static VkResult
···
743
742
static void
744
743
comp_window_direct_get_randr_outputs(struct comp_window_direct *w)
745
744
{
745
+
xcb_connection_t *connection = XGetXCBConnection(w->dpy);
746
746
xcb_randr_query_version_cookie_t version_cookie =
747
-
xcb_randr_query_version(w->connection, XCB_RANDR_MAJOR_VERSION,
747
+
xcb_randr_query_version(connection, XCB_RANDR_MAJOR_VERSION,
748
748
XCB_RANDR_MINOR_VERSION);
749
749
xcb_randr_query_version_reply_t *version_reply =
750
-
xcb_randr_query_version_reply(w->connection, version_cookie, NULL);
750
+
xcb_randr_query_version_reply(connection, version_cookie, NULL);
751
751
752
752
if (version_reply == nullptr) {
753
753
COMP_ERROR(w->base.c, "Could not get RandR version.");
···
766
766
767
767
xcb_generic_error_t *error = nullptr;
768
768
xcb_intern_atom_cookie_t non_desktop_cookie = xcb_intern_atom(
769
-
w->connection, 1, strlen("non-desktop"), "non-desktop");
769
+
connection, 1, strlen("non-desktop"), "non-desktop");
770
770
xcb_intern_atom_reply_t *non_desktop_reply =
771
-
xcb_intern_atom_reply(w->connection, non_desktop_cookie, &error);
771
+
xcb_intern_atom_reply(connection, non_desktop_cookie, &error);
772
772
773
773
if (error != nullptr) {
774
774
COMP_ERROR(w->base.c, "xcb_intern_atom_reply returned error %d",
···
787
787
}
788
788
789
789
xcb_randr_get_screen_resources_cookie_t resources_cookie =
790
-
xcb_randr_get_screen_resources(w->connection, w->screen->root);
790
+
xcb_randr_get_screen_resources(connection, w->screen->root);
791
791
xcb_randr_get_screen_resources_reply_t *resources_reply =
792
-
xcb_randr_get_screen_resources_reply(w->connection,
793
-
resources_cookie, nullptr);
792
+
xcb_randr_get_screen_resources_reply(connection, resources_cookie,
793
+
nullptr);
794
794
xcb_randr_output_t *xcb_outputs =
795
795
xcb_randr_get_screen_resources_outputs(resources_reply);
796
796
···
804
804
805
805
for (int i = 0; i < count; i++) {
806
806
xcb_randr_get_output_info_cookie_t output_cookie =
807
-
xcb_randr_get_output_info(w->connection, xcb_outputs[i],
807
+
xcb_randr_get_output_info(connection, xcb_outputs[i],
808
808
XCB_CURRENT_TIME);
809
809
xcb_randr_get_output_info_reply_t *output_reply =
810
-
xcb_randr_get_output_info_reply(w->connection,
811
-
output_cookie, nullptr);
810
+
xcb_randr_get_output_info_reply(connection, output_cookie,
811
+
nullptr);
812
812
813
813
// Only outputs with an available mode should be used
814
814
// (it is possible to see 'ghost' outputs with non-desktop=1).
···
828
828
// Find the first output that has the non-desktop property set.
829
829
xcb_randr_get_output_property_cookie_t prop_cookie;
830
830
prop_cookie = xcb_randr_get_output_property(
831
-
w->connection, xcb_outputs[i], non_desktop_reply->atom,
831
+
connection, xcb_outputs[i], non_desktop_reply->atom,
832
832
XCB_ATOM_NONE, 0, 4, 0, 0);
833
833
xcb_randr_get_output_property_reply_t *prop_reply = nullptr;
834
834
prop_reply = xcb_randr_get_output_property_reply(
835
-
w->connection, prop_cookie, &error);
835
+
connection, prop_cookie, &error);
836
836
if (error != nullptr) {
837
837
COMP_ERROR(w->base.c,
838
838
"xcb_randr_get_output_property_reply "