QEglContext::createSurface() failed in embedded Qt 4.8.0

[Kaijun]

When I run hello_es2 built in embedded Qt 4.8.0 and SGX Gaphics_SDK_4_05_00_03 in BB xM board, it failed with
QEglContext::createSurface(): Unable to create EGL surface, error = 0x300b, then I set windowDrawable to zero in

surf = eglCreateWindowSurface
(context->display(), context->config(), windowDrawable, props);

it works, it seems there is a bug in createNativeWindow(static_cast<QWidget *>(device), &windowDrawable) of qgl_qws.cpp.

But when I run my application,
myapp -qws -display powervr
it failed in the second call to eglCreateWindowSurface with
QEglContext::createSurface(): Unable to create EGL surface, error = 0x3003.
I have patched Qt as someone suggested (https://e2e.ti.com/support/dsp/omap_...f/447/t/101221)
and set powervr.ini to
WindowSystem=libpvrQWSWSEGL.so.

In the second and later calls, I created sub-QGLWidgets shared with main windows. My application used to work in Qt 4.7.4. and old SGX SDK. Here is my config
WSEGL settings
[default]
WindowSystem=libpvrQWSWSEGL.so
------
ARM CPU information
Processor : ARMv7 Processor rev 2 (v7l)
BogoMIPS : 996.71
Features : swp half thumb fastmult vfp edsp thumbee neon vfpv3
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x3
CPU part : 0xc08
CPU revision : 2

Hardware : OMAP3 Beagle Board
Revision : 0020
Serial : 0000000000000000
------
SGX driver information
Version 1.6.16.4117 (release) /home/tang/Projects/OE/setup-scripts/build/tmp-angstrom_v2012_05-eglibc/work/beagleboard-angstrom-linux-gnueabi/omap3-sgx-modules-4.05.00.03-r125b/Graphics_SDK_4_05_00_03/GFX_Linux_KM
System Version String: SGX revision = 1.2.5
------
Framebuffer settings

mode "1360x768-60"
# D: 72.010 MHz, H: 47.375 kHz, V: 59.968 Hz
geometry 1360 768 1360 2304 32
timings 13887 80 48 3 9 32 10
rgba 8/16,8/8,8/0,8/24
endmode

Frame buffer device information:
Name : omapfb
Address : 0x86000000
Size : 12582912
Type : PACKED PIXELS
Visual : TRUECOLOR
XPanStep : 1
YPanStep : 1
YWrapStep : 0
LineLength : 5440
Accelerator : No
------
Rotation settings
0
------
Kernel Module information
Module Size Used by
bufferclass_ti 5064 0
omaplfb 11963 0
pvrsrvkm 148853 2 bufferclass_ti,omaplfb
sdmak 4622 0
lpm_omap3530 6967 0
dsplinkk 128609 1 lpm_omap3530
cmemk 22859 0
------
Boot settings
console=tty0 console=ttyO2,115200n8 consoleblank=1 mem=128M@0x80000000 psplash=false omapdss.debug=y loglevel=8 mpurate=1000 buddy=none camera=lbcm3m1 vram=32M omapfb.mode=dvi:1360x768MR-24@60 omapfb.vram=0:12M,1:12M,2:8M omapdss.def_disp=dvi root=/dev/mmcblk0p2 rw rootfstype=ext3 rootwait
------
Linux Kernel version
Linux beagleboard 2.6.37 #1 Fri May 29 16:26:50 BST 2015 armv7l GNU/Linux

I have tried different vram size, I don't know why it still fails.
Any idea?