求助：beryl问题

initt

开启beryl,程序之间切换流畅。
程序内部窗口切换不了（firefox中的标签页），只有最小化再最大化后才能切换过去....

运行glxgears,显示如下（intel 852/55集成显卡）：
debian:~# glxgears
libGL warning: 3D driver claims to not support visual 0x55
do_wait: drmWaitVBlank returned -1, IRQs don't seem to be working correctly.
Try running with LIBGL_THROTTLE_REFRESH and LIBL_SYNC_REFRESH unset.
5157 frames in 5.0 seconds = 1031.230 FPS
5326 frames in 5.0 seconds = 1065.129 FPS
5321 frames in 5.0 seconds = 1064.168 FPS
5345 frames in 5.0 seconds = 1068.876 FPS

急待解决，谢谢哥们了