ui/console: Remove dpy_cursor_define_supported()

Remove dpy_cursor_define_supported() as it brings no benefit today and
it has a few inherent problems.

All graphical displays except egl-headless support cursor composition
without DMA-BUF, and egl-headless is meant to be used in conjunction
with another graphical display, so dpy_cursor_define_supported()
always returns true and meaningless.

Even if we add a new display without cursor composition in the future,
dpy_cursor_define_supported() will be problematic as a cursor display
fix for it because some display devices like virtio-gpu cannot tell the
lack of cursor composition capability to the guest and are unable to
utilize the value the function returns. Therefore, all non-headless
graphical displays must actually implement cursor composition for
correct cursor display.

Another problem with dpy_cursor_define_supported() is that it returns
true even if only some of the display listeners support cursor
composition, which is wrong unless all display listeners that lack
cursor composition is headless.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Phil Dennis-Jordan <phil@philjordan.eu>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-ID: <20240715-cursor-v3-4-afa5b9492dbf@daynix.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/display/qxl-render.c

@@ -307,10 +307,6 @@ int qxl_render_cursor(PCIQXLDevice *qxl, QXLCommandExt *ext)
         return 1;
     }
 
-    if (!dpy_cursor_define_supported(qxl->vga.con)) {
-        return 0;
-    }
-
     if (qxl->debug > 1 && cmd->type != QXL_CURSOR_MOVE) {
         fprintf(stderr, "%s", __func__);
         qxl_log_cmd_cursor(qxl, cmd, ext->group_id);

hw/display/vmware_vga.c

@@ -904,10 +904,8 @@ static uint32_t vmsvga_value_read(void *opaque, uint32_t address)
         caps |= SVGA_CAP_RECT_FILL;
 #endif
 #ifdef HW_MOUSE_ACCEL
-        if (dpy_cursor_define_supported(s->vga.con)) {
-            caps |= SVGA_CAP_CURSOR | SVGA_CAP_CURSOR_BYPASS_2 |
-                    SVGA_CAP_CURSOR_BYPASS;
-        }
+        caps |= SVGA_CAP_CURSOR | SVGA_CAP_CURSOR_BYPASS_2 |
+                SVGA_CAP_CURSOR_BYPASS;
 #endif
         ret = caps;
         break;

include/ui/console.h

@@ -324,7 +324,6 @@ void dpy_text_update(QemuConsole *con, int x, int y, int w, int h);
 void dpy_text_resize(QemuConsole *con, int w, int h);
 void dpy_mouse_set(QemuConsole *con, int x, int y, bool on);
 void dpy_cursor_define(QemuConsole *con, QEMUCursor *cursor);
-bool dpy_cursor_define_supported(QemuConsole *con);
 bool dpy_gfx_check_format(QemuConsole *con,
                           pixman_format_code_t format);
 

ui/console.c

@@ -1001,19 +1001,6 @@ void dpy_cursor_define(QemuConsole *c, QEMUCursor *cursor)
     }
 }
 
-bool dpy_cursor_define_supported(QemuConsole *con)
-{
-    DisplayState *s = con->ds;
-    DisplayChangeListener *dcl;
-
-    QLIST_FOREACH(dcl, &s->listeners, next) {
-        if (dcl->ops->dpy_cursor_define) {
-            return true;
-        }
-    }
-    return false;
-}
-
 QEMUGLContext dpy_gl_ctx_create(QemuConsole *con,
                                 struct QEMUGLParams *qparams)
 {