Sheng Yu wrote: > I have been tracking for a bug that makes my program crashing when > calling function glXMakeCurrent. > My program runs with multi-displays, ':0.0', ':1.0', ':1.1', ':2.0', > ':2.1'. When glXMakeCurrent() is called > to switch rendering context from ':0.0' to either ':1.0', ':1.1' or > ':2.0', ':2.1', the program runs fine. > However, if the rendering context is switch from ':1.1' to ':2.0', > the program crashes with with a > segmentation fault. > > The interesting thing I found when debugging is the window ID and > root window ID for each display: > display:':0.0',screen: 0, root window id: 315, window id: 71303171 > display:':1.0',screen: 0, root window id: 595, window id: 2097156 > display:':1.1',screen: 1, root window id: 597, window id: 4194308 > display:':2.0',screen: 0, root window id: 595, window id: 2097156 > display:':2.1',screen: 1, root window id: 597, window id: 4194308 > > It seems that X Server 1 and 2 assign window ID with the same > strategy, which is different from X Server 0. > I am wondering whether it is causing the crashing, which indicates > problems in X Server settings. I have > been digging into the source of X Server and I cannot find how the > window ID is assigned. Could someone > tell me which file I should look into? Thanks a lot!
The X server doesn't assign individual XIDs (except for resources which are created internally by the server, e.g. the root window). Each client is assigned a block of XIDs upon connection, and the client (i.e. Xlib) allocates XIDs from this block. It would be more clear if you print the XIDs in hexadecimal: display:':0.0',screen: 0, root window id: 13b, window id: 4400003 display:':1.0',screen: 0, root window id: 253, window id: 200004 display:':1.1',screen: 1, root window id: 255, window id: 400004 display:':2.0',screen: 0, root window id: 253, window id: 200004 display:':2.1',screen: 1, root window id: 255, window id: 400004 The most significant 11 bits of the XID indicate the client, leaving 21 bits for each client, giving each client 2^21 (= 2,097,152) XIDs. In any case, I doubt that this has anything to do with your problems with OpenGL. -- Glynn Clements <[email protected]> _______________________________________________ xorg mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/xorg
