Lorenzo Desole      2009-04-19 07:36:10 PDT

I am one of the developers of a multimedia application (My Media System MMS),
which uses SDL.

MMS is normally running in fullscreen mode but it switches it off before
launching external applications (mplayer, xine, etc.).

The problem with fullscreen is that when the latter is switched off either via
SDL_WM_ToggleFullScreen() or SDL_SetVideoMode(), SDL compares the current
screen sizes with the ones saved when the video system was initted, and if they
don't match, it calls XF86VidModeSwitchToMode() to switch to the old modeline.

This makes it impossible for external programs and for MMS itself to use RandR
to change the screen size, because next time fullscreen mode is turned off, it
bombs out with the following error:

X Error of failed request:  BadValue (integer parameter out of range for
operation)
Major opcode of failed request:  136 (XFree86-VidModeExtension)
Minor opcode of failed request:  10 (XF86VidModeSwitchToMode)
[...]

Obviously this happens only if the new screen resolution is smaller than the
original one and XF86VidModeSwitchToMode() can't succeed.

I couldn't find any way to inform SDL that the screen resolution it uses as
reference is no longer valid.

This can be fixed by adding "save_mode(this)" to
./src/video/x11/SDL_x11modes.c, API X11_EnterFullScreen(_THIS), like this:

int X11_EnterFullScreen(_THIS)
{
    int okay;
+    save_mode(this);

I can't rule out possible side effects, but I don't see any.

While I admit this is a minor issue for the general users, it is a major
showstopper for our program where the ability to change screen resolution and
refresh rate according to the movie being played, is very important.

Thanks in advance.