X Client requests fail for GTK based window - linux

Question

I have created a simple gstreamer+gtk based application to play video file. "filesrc", "decodebin", "autovideosink", "autoaudiosink" gstreamer elements are used for that.
Main window is created using gtk_window_new(GTK_WINDOW_TOPLEVEL) and drawing area is created using gtk_drawing_area_new(). Drawing window is embedded in main window.
To render on gtk drawing window, its handle is passed to gstreamer video plugin as overlay using gstreamer api gst_video_overlay_set_window_handle()
By doing so video is not rendered only audio gets played.
Instead of GTK window if i pass XCreateWindow() handle to gstreamer video plugin as overlay then everything works fine. But i have to create GTK based player.
Now, when i start debugging the issue i have found below details.
"autovideosink" plugin gets blocked on XNextEvent inside mainloop thread(Luckily i have source code and verified using logs)
Then using xtrace utility it was found that most of X Request gets failed(See below) whereas in case of XCreateWindow all such Request gets successful Response.
002:<:000f: 52: Request(1): CreateWindow depth=0x18 window=0x01600001 parent=0x01400007 x=0 y=0 width=640 height=368 border-width=0 class=InputOutput(0x0001) visual=0x00000021 value-list={background-pixel=0x00000000 border-pixel=0x00000000 backing-store=NotUseful(0x00) override-redirect=false(0x00) colormap=CopyFromParent(0x00000000)}
002:<:0010: 24: Request(16): InternAtom only-if-exists=true(0x01) name='_NET_WM_STATE'
002:>:000f:Error 8=Match: major=1, minor=0, bad=20971527
002:<:001d: 8: Request(3): GetWindowAttributes window=0x01600001
002:<:001e: 8: Request(14): GetGeometry drawable=0x01600001
002:>:001d:Error 3=Window: major=3, minor=0, bad=23068673
002:>:001e:Error 9=Drawable: major=14, minor=0, bad=23068673
I have no idea why these requests gets failed for GTK window. Whereas in my old system(ubuntu 14.04) i can run the same player very well. Current system is ubuntu 16.04
Any X Server related configuration setting doing that?
Please suggest some solution or any idea how to debug it further to catch the real cause.

Answer 1

Prototype:
XCreateWindow(display, parent, x, y, width, height, border_width, depth, class, visual, valuemask, attributes)
autovideosink mentioned in question is actually imxeglvivsink. imxeglvivsink creates child window with gtk-window as parent(Check second parameter of XCreateWindow api).
Now GDK default Visual used for Parent Windodw(GTK) were different from X default Visual and this is the reason X CreateWindow Request gets failed.
I solved this problem with 2 solutions.
Solution 1:
In imxeglvivsink, while creating child window i used 'CopyFromParent' flag for 'visual' parameter of XCreateWindow api. By doing so, Visual for Parent and Child matches and X request CreateWindow gets successful.
I didn't like this solution as i have to replace original imxeglvivsink library with my new library.
Solution 2:
My ultimate goal is still same. I have to keep same visual for parent and child window. In this solution i changed Visual of Parent window(GTK) to X Default Visual. I did this change at application level and i don't have any dependency of imxeglvivsink. Code snippet to change GDK visual is below:
static int change_visual(GtkWidget *widget)
{
int nitems_return;
Display *x_display = XOpenDisplay(NULL);
Visual *x_visual = XDefaultVisual(x_display, DefaultScreen(x_display));
GdkScreen *gdk_screen = gdk_screen_get_default();
GList *gdk_visual_list = gdk_screen_list_visuals(gdk_screen);
GList *l;
for (l = gdk_visual_list; l != NULL; l = l->next)
{
Visual *temp = gdk_x11_visual_get_xvisual((GdkVisual *)l->data);
if(temp->visualid == x_visual->visualid) break;
}
//l is pointing the visual which is similar to system x visual. Lets change it.
gtk_widget_set_visual (widget, (GdkVisual *)l->data);
return 0;
}
I know i don't take care if visualid don't match inside the for loop. For me i always find GDK visual same to X Default Visual.