X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fvideo%2Fconsole%2Ffbcon.h;h=71643f5ad94f487769d8615f9c265d5ebfa978d6;hb=9bf4aaab3e101692164d49b7ca357651eb691cb6;hp=a9d036b0ac426fc5dc1cefe6ffa90b203e1a39ca;hpb=db216c3d5e4c040e557a50f8f5d35d5c415e8c1c;p=linux-2.6.git

diff --git a/drivers/video/console/fbcon.h b/drivers/video/console/fbcon.h
index a9d036b0a..71643f5ad 100644
--- a/drivers/video/console/fbcon.h
+++ b/drivers/video/console/fbcon.h
@@ -36,7 +36,7 @@ struct display {
 };
 
 /* drivers/video/console/fbcon.c */
-extern char con2fb_map[MAX_NR_CONSOLES];
+extern signed char con2fb_map[MAX_NR_CONSOLES];
 extern int set_con2fb_map(int unit, int newidx);
 
     /*
@@ -67,40 +67,57 @@ extern int set_con2fb_map(int unit, int newidx);
      *  Scroll Method
      */
      
-/* Internal flags */
-#define __SCROLL_YPAN		0x001
-#define __SCROLL_YWRAP		0x002
-#define __SCROLL_YMOVE		0x003
-#define __SCROLL_YREDRAW	0x004
-#define __SCROLL_YMASK		0x00f
-#define __SCROLL_YFIXED		0x010
-#define __SCROLL_YNOMOVE	0x020
-#define __SCROLL_YPANREDRAW	0x040
-#define __SCROLL_YNOPARTIAL	0x080
-
-/* Only these should be used by the drivers */
-/* Which one should you use? If you have a fast card and slow bus,
-   then probably just 0 to indicate fbcon should choose between
-   YWRAP/YPAN+MOVE/YMOVE. On the other side, if you have a fast bus
-   and even better if your card can do fonting (1->8/32bit painting),
-   you should consider either SCROLL_YREDRAW (if your card is
-   able to do neither YPAN/YWRAP), or SCROLL_YNOMOVE.
-   The best is to test it with some real life scrolling (usually, not
-   all lines on the screen are filled completely with non-space characters,
-   and REDRAW performs much better on such lines, so don't cat a file
-   with every line covering all screen columns, it would not be the right
-   benchmark).
+/* There are several methods fbcon can use to move text around the screen:
+ *
+ *                     Operation   Pan    Wrap
+ *---------------------------------------------
+ * SCROLL_MOVE         copyarea    No     No
+ * SCROLL_PAN_MOVE     copyarea    Yes    No
+ * SCROLL_WRAP_MOVE    copyarea    No     Yes
+ * SCROLL_REDRAW       imageblit   No     No
+ * SCROLL_PAN_REDRAW   imageblit   Yes    No
+ * SCROLL_WRAP_REDRAW  imageblit   No     Yes
+ *
+ * (SCROLL_WRAP_REDRAW is not implemented yet)
+ *
+ * In general, fbcon will choose the best scrolling
+ * method based on the rule below:
+ *
+ * Pan/Wrap > accel imageblit > accel copyarea >
+ * soft imageblit > (soft copyarea)
+ *
+ * Exception to the rule: Pan + accel copyarea is
+ * preferred over Pan + accel imageblit.
+ *
+ * The above is typical for PCI/AGP cards. Unless
+ * overridden, fbcon will never use soft copyarea.
+ *
+ * If you need to override the above rule, set the
+ * appropriate flags in fb_info->flags.  For example,
+ * to prefer copyarea over imageblit, set
+ * FBINFO_READS_FAST.
+ *
+ * Other notes:
+ * + use the hardware engine to move the text
+ *    (hw-accelerated copyarea() and fillrect())
+ * + use hardware-supported panning on a large virtual screen
+ * + amifb can not only pan, but also wrap the display by N lines
+ *    (i.e. visible line i = physical line (i+N) % yres).
+ * + read what's already rendered on the screen and
+ *     write it in a different place (this is cfb_copyarea())
+ * + re-render the text to the screen
+ *
+ * Whether to use wrapping or panning can only be figured out at
+ * runtime (when we know whether our font height is a multiple
+ * of the pan/wrap step)
+ *
  */
-#define SCROLL_YREDRAW		(__SCROLL_YFIXED|__SCROLL_YREDRAW)
-#define SCROLL_YNOMOVE		(__SCROLL_YNOMOVE|__SCROLL_YPANREDRAW)
 
-/* SCROLL_YNOPARTIAL, used in combination with the above, is for video
-   cards which can not handle using panning to scroll a portion of the
-   screen without excessive flicker.  Panning will only be used for
-   whole screens.
- */
-/* Namespace consistency */
-#define SCROLL_YNOPARTIAL	__SCROLL_YNOPARTIAL
+#define SCROLL_MOVE	   0x001
+#define SCROLL_PAN_MOVE	   0x002
+#define SCROLL_WRAP_MOVE   0x003
+#define SCROLL_REDRAW	   0x004
+#define SCROLL_PAN_REDRAW  0x005
 
 extern int fb_console_init(void);