linux/fbdev.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <sys/types.h>
   5 #include <sys/stat.h>
   6 #include <fcntl.h>
   7 #include <sys/ioctl.h>
   8 #include <sys/mman.h>
   9 #include <unistd.h>
  10 #include <linux/fb.h>
  11 #include <linux/matroxfb.h>
  12
  13 #include "fbdev.h"
  14
  15 #define FBDEV_MAX_BUFFERS 3
  16
  17 struct vout_fbdev {
  18         int     fd;
  19         void    *mem;
  20         size_t  mem_size;
  21         struct  fb_var_screeninfo fbvar_old;
  22         struct  fb_var_screeninfo fbvar_new;
  23         int     buffer_write;
  24         int     fb_size;
  25         int     buffer_count;
  26         int     top_border, bottom_border;
  27 };
  28
  29 void *vout_fbdev_flip(struct vout_fbdev *fbdev)
  30 {
  31         int draw_buf;
  32
  33         if (fbdev->buffer_count < 2)
  34                 return fbdev->mem;
  35
  36         draw_buf = fbdev->buffer_write;
  37         fbdev->buffer_write++;
  38         if (fbdev->buffer_write >= fbdev->buffer_count)
  39                 fbdev->buffer_write = 0;
  40
  41         fbdev->fbvar_new.yoffset =
  42                 (fbdev->top_border + fbdev->fbvar_new.yres + fbdev->bottom_border) * draw_buf +
  43                 fbdev->top_border;
  44
  45         ioctl(fbdev->fd, FBIOPAN_DISPLAY, &fbdev->fbvar_new);
  46
  47         return (char *)fbdev->mem + fbdev->fb_size * fbdev->buffer_write;
  48 }
  49
  50 void vout_fbdev_wait_vsync(struct vout_fbdev *fbdev)
  51 {
  52         int arg = 0;
  53         ioctl(fbdev->fd, FBIO_WAITFORVSYNC, &arg);
  54 }
  55
  56 int vout_fbdev_resize(struct vout_fbdev *fbdev, int w, int h,
  57                       int left_border, int right_border, int top_border, int bottom_border, int no_dblbuf)
  58 {
  59         int w_total = left_border + w + right_border;
  60         int h_total = top_border + h + bottom_border;
  61         size_t mem_size;
  62         int ret;
  63
  64         // unblank to be sure the mode is really accepted
  65         ioctl(fbdev->fd, FBIOBLANK, FB_BLANK_UNBLANK);
  66
  67         if (fbdev->fbvar_new.bits_per_pixel != 16 ||
  68                         w != fbdev->fbvar_new.xres ||
  69                         h != fbdev->fbvar_new.yres ||
  70                         w_total != fbdev->fbvar_new.xres_virtual ||
  71                         h_total > fbdev->fbvar_new.yres_virtual ||
  72                         left_border != fbdev->fbvar_new.xoffset) {
  73                 fbdev->fbvar_new.xres = w;
  74                 fbdev->fbvar_new.yres = h;
  75                 fbdev->fbvar_new.xres_virtual = w_total;
  76                 fbdev->fbvar_new.yres_virtual = h_total;
  77                 fbdev->fbvar_new.xoffset = left_border;
  78                 fbdev->fbvar_new.bits_per_pixel = 16;
  79                 printf(" switching to %dx%d@16\n", w, h);
  80                 ret = ioctl(fbdev->fd, FBIOPUT_VSCREENINFO, &fbdev->fbvar_new);
  81                 if (ret == -1) {
  82                         perror("FBIOPUT_VSCREENINFO ioctl");
  83                         return -1;
  84                 }
  85         }
  86
  87         fbdev->buffer_count = FBDEV_MAX_BUFFERS; // be optimistic
  88         if (no_dblbuf)
  89                 fbdev->buffer_count = 1;
  90
  91         if (fbdev->fbvar_new.yres_virtual < h_total * fbdev->buffer_count) {
  92                 fbdev->fbvar_new.yres_virtual = h_total * fbdev->buffer_count;
  93                 ret = ioctl(fbdev->fd, FBIOPUT_VSCREENINFO, &fbdev->fbvar_new);
  94                 if (ret == -1) {
  95                         fbdev->buffer_count = 1;
  96                         fprintf(stderr, "Warning: failed to increase virtual resolution, "
  97                                         "doublebuffering disabled\n");
  98                 }
  99         }
 100
 101         fbdev->fb_size = w_total * h_total * 2;
 102         fbdev->top_border = top_border;
 103         fbdev->bottom_border = bottom_border;
 104
 105         mem_size = fbdev->fb_size * fbdev->buffer_count;
 106         if (fbdev->mem_size >= mem_size)
 107                 return 0;
 108
 109         if (fbdev->mem != NULL)
 110                 munmap(fbdev->mem, fbdev->mem_size);
 111
 112         fbdev->mem = mmap(0, mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev->fd, 0);
 113         if (fbdev->mem == MAP_FAILED && fbdev->buffer_count > 1) {
 114                 fprintf(stderr, "Warning: can't map %zd bytes, doublebuffering disabled\n", fbdev->mem_size);
 115                 fbdev->buffer_count = 1;
 116                 mem_size = fbdev->fb_size;
 117                 fbdev->mem = mmap(0, mem_size, PROT_WRITE|PROT_READ, MAP_SHARED, fbdev->fd, 0);
 118         }
 119         if (fbdev->mem == MAP_FAILED) {
 120                 fbdev->mem = NULL;
 121                 fbdev->mem_size = 0;
 122                 perror("mmap framebuffer");
 123                 return -1;
 124         }
 125
 126         fbdev->mem_size = mem_size;
 127         return 0;
 128 }
 129
 130 void vout_fbdev_clear(struct vout_fbdev *fbdev)
 131 {
 132         memset(fbdev->mem, 0, fbdev->mem_size);
 133 }
 134
 135 void vout_fbdev_clear_lines(struct vout_fbdev *fbdev, int y, int count)
 136 {
 137         int stride = fbdev->fbvar_new.xres_virtual * fbdev->fbvar_new.bits_per_pixel / 8;
 138         int i;
 139
 140         if (y + count > fbdev->top_border + fbdev->fbvar_new.yres)
 141                 count = fbdev->top_border + fbdev->fbvar_new.yres - y;
 142
 143         if (y >= 0 && count > 0)
 144                 for (i = 0; i < fbdev->buffer_count; i++)
 145                         memset((char *)fbdev->mem + fbdev->fb_size * i + y * stride, 0, stride * count);
 146 }
 147
 148 int vout_fbdev_get_fd(struct vout_fbdev *fbdev)
 149 {
 150         return fbdev->fd;
 151 }
 152
 153 struct vout_fbdev *vout_fbdev_init(const char *fbdev_name, int *w, int *h, int no_dblbuf)
 154 {
 155         struct vout_fbdev *fbdev;
 156         int req_w, req_h;
 157         int ret;
 158
 159         fbdev = calloc(1, sizeof(*fbdev));
 160         if (fbdev == NULL)
 161                 return NULL;
 162
 163         fbdev->fd = open(fbdev_name, O_RDWR);
 164         if (fbdev->fd == -1) {
 165                 fprintf(stderr, "%s: ", fbdev_name);
 166                 perror("open");
 167                 goto fail_open;
 168         }
 169
 170         ret = ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->fbvar_old);
 171         if (ret == -1) {
 172                 perror("FBIOGET_VSCREENINFO ioctl");
 173                 goto fail;
 174         }
 175
 176         fbdev->fbvar_new = fbdev->fbvar_old;
 177
 178         req_w = fbdev->fbvar_new.xres;
 179         if (*w != 0)
 180                 req_w = *w;
 181         req_h = fbdev->fbvar_new.yres;
 182         if (*h != 0)
 183                 req_h = *h;
 184
 185         ret = vout_fbdev_resize(fbdev, req_w, req_h, 0, 0, 0, 0, no_dblbuf);
 186         if (ret != 0)
 187                 goto fail;
 188
 189         printf("%s: %ix%i@%d\n", fbdev_name, fbdev->fbvar_new.xres, fbdev->fbvar_new.yres,
 190                 fbdev->fbvar_new.bits_per_pixel);
 191         *w = fbdev->fbvar_new.xres;
 192         *h = fbdev->fbvar_new.yres;
 193
 194         memset(fbdev->mem, 0, fbdev->mem_size);
 195
 196         // some checks
 197         ret = 0;
 198         ret = ioctl(fbdev->fd, FBIO_WAITFORVSYNC, &ret);
 199         if (ret != 0)
 200                 fprintf(stderr, "Warning: vsync doesn't seem to be supported\n");
 201
 202         if (fbdev->buffer_count > 1) {
 203                 fbdev->buffer_write = 0;
 204                 fbdev->fbvar_new.yoffset = fbdev->fbvar_new.yres * (fbdev->buffer_count - 1);
 205                 ret = ioctl(fbdev->fd, FBIOPAN_DISPLAY, &fbdev->fbvar_new);
 206                 if (ret != 0) {
 207                         fbdev->buffer_count = 1;
 208                         fprintf(stderr, "Warning: can't pan display, doublebuffering disabled\n");
 209                 }
 210         }
 211
 212         printf("fbdev initialized.\n");
 213         return fbdev;
 214
 215 fail:
 216         close(fbdev->fd);
 217 fail_open:
 218         free(fbdev);
 219         return NULL;
 220 }
 221
 222 void vout_fbdev_finish(struct vout_fbdev *fbdev)
 223 {
 224         ioctl(fbdev->fd, FBIOPUT_VSCREENINFO, &fbdev->fbvar_old);
 225         if (fbdev->mem != MAP_FAILED)
 226                 munmap(fbdev->mem, fbdev->mem_size);
 227         if (fbdev->fd >= 0)
 228                 close(fbdev->fd);
 229         fbdev->mem = NULL;
 230         fbdev->fd = -1;
 231         free(fbdev);
 232 }
 233