Hi Vanfanel!
Did you ever resolve any of this? I have been hitting my head against the vsync (and pan using 'FBIOPAN_DISPLAY') in pure framebuffer code:
Code: Select all
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/fb.h>
#include <sys/mman.h>
int main(int argc, char* argv[])
{
int fbfd = 0;
struct fb_var_screeninfo vinfo_orig;
struct fb_var_screeninfo vinfo;
// Open the file for reading and writing
fbfd = open("/dev/fb0", O_RDWR);
if (!fbfd) {
printf("Error: cannot open framebuffer device.\n");
return(1);
}
printf("The framebuffer device was opened successfully.\n");
// Get variable screen information
if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
printf("Error reading variable information.\n");
}
// Store for reset
memcpy(&vinfo_orig, &vinfo, sizeof(struct fb_var_screeninfo));
// Set variable info
vinfo.xres = 320;
vinfo.yres = 240;
vinfo.xres_virtual = 320;
vinfo.yres_virtual = 480; // double the physical height
vinfo.bits_per_pixel = 8;
if (ioctl(fbfd, FBIOPUT_VSCREENINFO, &vinfo)) {
printf("Error setting variable information.\n");
}
long int screensize = vinfo.xres * vinfo.yres;
long int bufsize = vinfo.xres_virtual * vinfo.yres_virtual;
char *fbp = 0;
int vs = 0;
int y = 0;
// Map fb to user mem
fbp = (char*)mmap(0, bufsize, PROT_READ | PROT_WRITE, MAP_SHARED, fbfd, 0);
if ((int)fbp == -1) {
printf("Failed to mmap.\n");
}
else {
// draw a blue rect at the upper half of screen
memset(fbp, 1, screensize / 2);
// draw a red rect at the lower half of screen
memset(fbp + screensize / 2, 4, screensize / 2);
// draw a green rect at the upper half of 2nd screen
memset(fbp + screensize, 2, screensize / 2);
// draw a green rect at the lower half of 2nd screen
memset(fbp + screensize + screensize / 2, 2, screensize / 2);
sleep(2);
// change to show lower half
if (ioctl(fbfd, FBIO_WAITFORVSYNC, 0)) {
printf("VSync failed.\n");
}
vinfo.yoffset = vinfo.yres;
if (ioctl(fbfd, FBIOPAN_DISPLAY, &vinfo)) {
printf("Pan failed.\n");
}
// wait
sleep(2);
}
// Cleanup
munmap(fbp, screensize);
if (ioctl(fbfd, FBIOPUT_VSCREENINFO, &vinfo_orig)) {
printf("Error re-setting variable information.\n");
}
close(fbfd);
return 0;
}
...where both vsync and pan just fail (return -1)
The fb driver source here
https://github.com/raspberrypi/linux/bl ... m2708_fb.c looks like there would be no support for vsync - but I have not the faintest idea how the Linux drivers are built... Using the dispmanx (vc_dispmanx_update_submit_sync) the vsync seems to work fine.
Regards,
JP
http://raspberrycompote.blogspot.com/ - Low-level graphics and 'Coding Gold Dust'
