Re: [AD] fbcon driver color depth

[Evert Glebbeek <eglebbk@xxxxxxxxxx>]

On Saturday 06 January 2007 21:44, Evert Glebbeek wrote:
> I'll see if I can hack something together then... been a while, so I may 
be 
> a bit rusty. I also won't be able to test it, but I'm sure someone else 
> can do that for me.

Patch attached. I actually also added a resolution getter while I was at 
it.
Tested in so far as I can say that it compiles on my system (so not 
actually tested at all). I'm not sure it does the right thing when it 
comes to loading the driver as a module.

I find the code a bit hackish, in particular because the fbdev graphics 
driver now inserts part of itself into the system driver. Ugly, but cannot 
be helped that I can see.
Tests and comments welcome!

Evert

Index: src/linux/fbcon.c
===================================================================
--- src/linux/fbcon.c	(revision 7690)
+++ src/linux/fbcon.c	(working copy)
@@ -97,6 +97,8 @@
 
 static char fb_desc[256] = EMPTY_STRING;     /* description string */
 
+static int fb_mode_read = FALSE;             /* has orig_mode been read? */
+
 static struct fb_fix_screeninfo fix_info;    /* read-only video mode info */
 static struct fb_var_screeninfo orig_mode;   /* original video mode info */
 static struct fb_var_screeninfo my_mode;     /* my video mode info */
@@ -188,6 +190,33 @@
 
 
 
+/* __al_linux_get_fb_color_depth:
+ *  Get the colour depth of the framebuffer
+ */
+int __al_linux_get_fb_color_depth(void)
+{
+   if ( (!fb_mode_read) && (fb_open_device() != 0) )
+      return 0;
+   return orig_mode.bits_per_pixel;
+}
+
+
+
+/* __al_linux_get_fb_resolution:
+ *  Get the resolution of the framebuffer
+ */
+int __al_linux_get_fb_resolution(int *width, int *height)
+{
+   if ( (!fb_mode_read) && (fb_open_device() != 0) )
+      return -1;
+
+   *width = orig_mode.xres;
+   *height = orig_mode.yres;
+   return 0;
+}
+
+
+
 /* fb_init:
  *  Sets a graphics mode.
  */
@@ -199,7 +228,7 @@
    char tmp[16];
 
    /* open framebuffer and store info in global variables */
-   if (fb_open_device() != 0)
+   if ( (!fb_mode_read) && (fb_open_device() != 0) )
       return NULL;
 
    /* look for a nice graphics mode in several passes */
@@ -548,6 +577,7 @@
    }
 
    TRACE(PREFIX_I "fb device %s opened successfully.\n", fname);
+   fb_mode_read = TRUE;
    return 0;
 }
 
@@ -1105,8 +1135,15 @@
  */
 void _module_init(int system_driver)
 {
-   if (system_driver == SYSTEM_LINUX)
+   if (system_driver == SYSTEM_LINUX) {
       _unix_register_gfx_driver(GFX_FBCON, &gfx_fbcon, TRUE, TRUE);
+      /* Register resolution and colour depth getters.
+       * This is a bit ugly because these are actually part of the
+       * system driver rather than the graphics driver...
+       */
+      system_linux.desktop_color_depth = __al_linux_get_fb_color_depth;
+      system_linux.get_desktop_resolution = __al_linux_get_fb_resolution;
+   }
 }
 
 #endif      /* ifdef ALLEGRO_MODULE */
Index: src/linux/lsystem.c
===================================================================
--- src/linux/lsystem.c	(revision 7690)
+++ src/linux/lsystem.c	(working copy)
@@ -42,6 +42,13 @@
 #endif
 
 
+#if (defined ALLEGRO_LINUX_FBCON) && (!defined ALLEGRO_WITH_MODULES)
+/* Functions for querying the framebuffer, for the fbcon driver */
+extern int __al_linux_get_fb_color_depth(void);
+extern int __al_linux_get_fb_resolution(int *width, int *height);
+#endif
+
+
 static int  sys_linux_init(void);
 static void sys_linux_exit(void);
 static void sys_linux_message (AL_CONST char *msg);
@@ -86,8 +93,13 @@
    NULL, /* get_vtable */
    __al_linux_set_display_switch_mode,
    __al_linux_display_switch_lock,
+#if (defined ALLEGRO_LINUX_FBCON) && (!defined ALLEGRO_WITH_MODULES)
+   __al_linux_get_fb_color_depth,
+   __al_linux_get_fb_resolution,
+#else
    NULL, /* desktop_color_depth */
    NULL, /* get_desktop_resolution */
+#endif
    NULL, /* get_gfx_safe_mode */
    _unix_yield_timeslice,
 #ifdef HAVE_LIBPTHREAD