possible progress on XO-1 camera issues

[John Gilmore]

> #10 0xb67fae59 in gst_xvimagesink_xvimage_put (xvimagesink=0x8364160)
>     at xvimagesink.c:864
>         src = {x = 134867456, y = 140758336, w = -1259457208, h = 1}
>         dst = {x = 137730309, y = 3, w = 0, h = 137691184}
>         result = {x = 0, y = 0, w = 322, h = 241}
>         draw_border = 322
>         __PRETTY_FUNCTION__ = "gst_xvimagesink_xvimage_put"
> 
> The src.w value is in the same range as the Xlib function addresses;
> -1259457208 is 0x4B11CAB8 and as can be seen from the call frame #9
> the XSync function is at 0x4b0eccf7.  The other values seem
> irrational.  This may be evidence that the stack has been corrupted
> somewhere else, or the values not initialised.

Just to rule out going too far down a blind alley...

Try adding a printf of these values to the code there, rather than or
in addition to using GDB.  GDB may not be 100% reliable when accessing
variables from optimized code.  (I used to maintain GDB, and I worked
very hard to make it never lie to you, but that precept hasn't always
been followed in the intervening decade, and optimizations have also
gotten a lot more complicated.)

Or try compiling that code without -O and see if that changes either
its behavior, or what the debugger reports.

	John