#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <linux/fb.h>
#include <sys/ioctl.h>
#define MXCFB_SET_GBL_ALPHA _IOW('F', 0x21, struct mxcfb_gbl_alpha)
struct mxcfb_gbl_alpha {
int enable;
int alpha;
};
int main(void)
{
int fd;
int done = 0;
struct mxcfb_gbl_alpha g_alpha;
fd = open("/dev/fb2", O_RDWR, 0);
g_alpha.alpha = 255;
g_alpha.enable = 1;
// ioctl(fd, MXCFB_SET_GBL_ALPHA, done, &g_alpha);
ioctl(fd, MXCFB_SET_GBL_ALPHA, &g_alpha);
printf("done=%d\n", done);
//close(fd);
printf("Bye!\n");
return 0;
}

(II) imx(1): Output DISP3 BG connected
(II) imx(1): Using sloppy heuristic for initial modes
(II) imx(1): Output DISP3 BG using initial mode builtin
(==) imx(1): DPI set to (96, 96)
(II) imx(0): bitsPerPixel=16 depth=16 defaultVisual=TrueColor
(II) imx(0): rgbOffset=11,5,0 rgbMask=0x0000f800,0x000007e0,0x0000001f
(II) imx(0): physAddr=0x7e000000 fbStart=0x2b170000 = 0x2b170000 + 0x00000000
(II) imx(0): reserve 4177920 bytes of frame buffer for screen
(II) imx(0): reserve same number of bytes for XRandR rotated screen at offset 4177920
(II) EXA(0): Driver allocated offscreen pixmaps
(II) EXA(0): Driver registered support for the following operations:
(II) Solid
(II) Copy
(II) Composite (RENDER acceleration)
(II) UploadToScreen
(II) DownloadFromScreen
(II) imx(0): Driver handles allocation of pixmaps
(II) imx(0): Offscreen pixmap area of 24608K bytes
(II) imx(0): IMX EXA acceleration setup successful
(==) imx(0): Backing store disabled
(==) imx(0): DPMS enabled
(II) imx(0): RandR 1.2 enabled, ignore the following RandR disabled message.
(==) imx(0): DPMS enabled
(II) imx(0): initial screen size = 1280x800
(--) RandR disabled
(II) imx(1): bitsPerPixel=16 depth=16 defaultVisual=TrueColor
(II) imx(1): rgbOffset=11,5,0 rgbMask=0x0000f800,0x000007e0,0x0000001f
(II) imx(1): physAddr=0x71000000 fbStart=0x2d189000 = 0x2d189000 + 0x00000000
(II) imx(1): reserve 4177920 bytes of frame buffer for screen
(II) imx(1): reserve same number of bytes for XRandR rotated screen at offset 4177920
(II) EXA(1): Driver allocated offscreen pixmaps
(II) EXA(1): Driver registered support for the following operations:
(II) Solid
(II) Copy
(II) Composite (RENDER acceleration)
(II) UploadToScreen
(II) DownloadFromScreen
(II) imx(1): Driver handles allocation of pixmaps
(II) imx(1): Offscreen pixmap area of 3990K bytes
(II) imx(1): IMX EXA acceleration setup successful
(==) imx(1): Backing store disabled
(==) imx(1): DPMS enabled
(II) imx(1): RandR 1.2 enabled, ignore the following RandR disabled message.
(==) imx(1): DPMS enabled
(II) imx(1): initial screen size = 800x480