X11: Wrong initial size in tiling WM (+ solution?)

[SDLBugzilla]

This bug report was migrated from our old Bugzilla tracker.

These attachments are available in the static archive:

• patch for X11_Wait(Un)Mapped (speculative.diff, text/plain, 2011-07-14 01:01:14 +0000, 2385 bytes)
• Same patch, but for SDL2 (bug1246.patch, application/octet-stream, 2012-06-21 02:43:05 +0000, 2366 bytes)

Reported in version: 1.2.14
Reported for operating system, platform: Linux, x86

Comments on the original bug report:

On 2011-07-14 01:01:14 +0000, Tony Lainson wrote:

Created attachment 646
patch for X11_Wait(Un)Mapped

SDL 1.2 often fails to observe a resize event if it happens just as the window is being created. No SDL_VIDEORESIZE event is sent to the application. Any extra space remains black.

X11_WaitMapped() (in src/video/x11/SDL_x11modes.c) drops resize events that arrive before the window is mapped (StructureNotifyMask selects both MapNotify and ConfigureNotify events). I think that might be a problem if the window manager resizes the window before mapping it. Neither of the WMs I tried actually do that, but I've attached a patch anyway.

The real problem is in try_mitshm() (src/video/x11/SDL_x11image.c): XSync is called with the "discard" parameter set to True, which nukes everything in the event queue. Is there a reason for that? Would anything break if we changed it to False?

The XSync(blah, True) calls in other files look deliberate. They make me uneasy, but I don't know what (if anything) should be done about them. In any case, I haven't seen the resize bug since I changed True to False in try_mitshm().

I'm not at all familiar with SDL 1.3, but it looks like the only surviving problem is the XSync in the SHM code (which I haven't tried to trigger). Nice work!

On 2011-12-29 01:44:00 +0000, Sam Lantinga wrote:

I'm hesitant to change X11 behavior in SDL 1.2. Thanks for the patch though!

On 2012-06-21 02:43:05 +0000, driedfruit wrote:

Created attachment 883
Same patch, but for SDL2

Made against 6335:fbb84f5b985f