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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <math.h>
#include <time.h>
#include <errno.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include <linux/fb.h>
int64_t systemTime()
{
struct timespec t;
t.tv_sec = t.tv_nsec = 0;
clock_gettime(CLOCK_MONOTONIC, &t);
return (int64_t)(t.tv_sec)*1000000000LL + t.tv_nsec;
}
int main(int argc, char** argv)
{
char const * const device_template[] = {
"/dev/graphics/fb%u",
"/dev/fb%u",
0 };
int fd = -1;
int i=0;
char name[64];
while ((fd==-1) && device_template[i]) {
snprintf(name, 64, device_template[i], 0);
fd = open(name, O_RDWR, 0);
i++;
}
if (fd < 0)
return -errno;
struct fb_fix_screeninfo finfo;
if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
return -errno;
struct fb_var_screeninfo info;
if (ioctl(fd, FBIOGET_VSCREENINFO, &info) == -1)
return -errno;
info.reserved[0] = 0;
info.reserved[1] = 0;
info.reserved[2] = 0;
info.xoffset = 0;
info.yoffset = 0;
info.bits_per_pixel = 16;
info.activate = FB_ACTIVATE_NOW;
if (ioctl(fd, FBIOPUT_VSCREENINFO, &info) == -1) {
printf("FBIOPUT_VSCREENINFO failed (%d x %d)\n",
info.xres_virtual, info.yres_virtual);
return 0;
}
if (ioctl(fd, FBIOGET_VSCREENINFO, &info) == -1)
return -errno;
uint64_t denominator = (uint64_t)( info.upper_margin + info.lower_margin + info.yres )
* ( info.left_margin + info.right_margin + info.xres )
* info.pixclock;
int refreshRate = denominator ? (1000000000000000LLU / denominator) : 0;
float xdpi = (info.xres * 25.4f) / info.width;
float ydpi = (info.yres * 25.4f) / info.height;
float fps = refreshRate / 1000.0f;
printf( "using (fd=%d)\n"
"id = %s\n"
"xres = %d px\n"
"yres = %d px\n"
"xres_virtual = %d px\n"
"yres_virtual = %d px\n"
"bpp = %d\n"
"r = %2u:%u\n"
"g = %2u:%u\n"
"b = %2u:%u\n",
fd,
finfo.id,
info.xres,
info.yres,
info.xres_virtual,
info.yres_virtual,
info.bits_per_pixel,
info.red.offset, info.red.length,
info.green.offset, info.green.length,
info.blue.offset, info.blue.length
);
printf( "width = %d mm (%f dpi)\n"
"height = %d mm (%f dpi)\n"
"refresh rate = %.2f Hz\n",
info.width, xdpi,
info.height, ydpi,
fps
);
printf("upper_margin=%d, lower_margin=%d, left_margin=%d, right_margin=%d, pixclock=%d, finfo.smem_len=%d\n",
info.upper_margin, info.lower_margin, info.left_margin, info.right_margin, info.pixclock, finfo.smem_len);
if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
return -errno;
if (finfo.smem_len <= 0)
return -errno;
/*
* Open and map the display.
*/
uint16_t* buffer = (uint16_t*) mmap(
0, finfo.smem_len,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd, 0);
if (buffer == MAP_FAILED)
return -errno;
// at least for now, always clear the fb
memset(buffer, 0, finfo.smem_len);
memset(buffer, 0xff, 320*(info.yres_virtual/2)*2);
int l,t,w,h;
l=0;
t=0;
w=320;
h=480;
info.reserved[0] = 0x54445055; // "UPDT";
info.reserved[1] = (uint16_t)l | ((uint32_t)t << 16);
info.reserved[2] = (uint16_t)(l+w) | ((uint32_t)(t+h) << 16);
int err;
int c = 0;
int64_t time = systemTime();
while (1) {
info.activate = FB_ACTIVATE_VBL;
info.yoffset = 0;
ioctl(fd, FBIOPUT_VSCREENINFO, &info);
info.activate = FB_ACTIVATE_VBL;
info.yoffset = info.yres_virtual/2;
err = ioctl(fd, FBIOPUT_VSCREENINFO, &info);
c+=2;
if (c==60*2) {
int64_t now = systemTime();
time = now - time;
printf("refresh rate = %f Hz\n", (c*1000000000.0 / (double)time));
c = 0;
time = now;
}
}
return 0;
}
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