what's "Adreno200-EGL(xxxx): eglLockWindowSurface: failed to map the memory for fd=yy offs=zz" " means?

in my application( only on ardeno200 gpu), after some time(3~4 min), my logcat start to log the error in the object...

es:

10-06 06:07:32.454: ERROR/Adreno200-EGL(14433): eglLockWindowSurface: failed to map the memory for fd=44 offs=3637248
10-06 06:07:32.504: ERROR/Adreno200-EGL(14433): eglLockWindowSurface: failed to map the memory for fd=46 offs=10067968
10-06 06:07:32.564: ERROR/Adreno200-EGL(14433): eglLockWindowSurface: failed to map the  memory for fd=44 offs=3637248
10-06 06:07:32.624: ERROR/Adreno200-EGL(14433): eglLockWindowSurface: failed to map the memory for fd=46 offs=10067968
10-06 06:07:32.684: ERROR/Adreno200-EGL(14433): eglLockWindowSurface: failed to map the  memory for fd=44 offs=3637248
10-06 06:07:32.734: ERROR/Adreno200-EGL(14433): eglLockWindowSurface: failed to map the memory for fd=46 offs=10067968
10-06 06:07:32.785: ERROR/Adreno200-EGL(14433): eglLockWindowSurface: failed to map the memory for fd=44 offs=3637248

i have found some other questio开发者_开发知识库n related on this error, but they don't apply on my case( one point out that i can't delete my textures on an another thread, not my case. the other point out that i may have loaded texture indefinitlely without freed them....not my case either, as i only load texture at start.)

it doesnt appear to be a memory issue by the way, as i have a lot of heap free ( i only use 5 mb) and the native allocation ( via ddms native heap monitor ) show like 120 mb allocated at creation time, then only 60~70 mb, fairly static, from the start to the error point(and even after). it also run indefinitely on other devices.....

i have currently no idea on how to deal with it, my best guess is to at least understand exaclty what that error is trying to tell me. i have searched for the source of the ardeno200 driver to find out myself, but without luck.