fbdev: Garbage collect fbdev scrolling acceleration, part 1 (from TODO list)

Scroll acceleration is disabled in fbcon by hard-wiring
p->scrollmode = SCROLL_REDRAW. Remove the obsolete code in fbcon.c
and fbdev/core/
Signed-off-by: Claudio Suarez <cssk@net-c.es>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YVXTYqszZix9TxjJ@gineta.localdomain

Documentation/gpu/todo.rst

@@ -314,16 +314,19 @@ Level: Advanced
 Garbage collect fbdev scrolling acceleration
 --------------------------------------------
 
-Scroll acceleration is disabled in fbcon by hard-wiring p->scrollmode =
-SCROLL_REDRAW. There's a ton of code this will allow us to remove:
+Scroll acceleration has been disabled in fbcon. Now it works as the old
+SCROLL_REDRAW mode. A ton of code was removed in fbcon.c and the hook bmove was
+removed from fbcon_ops.
+Remaining tasks:
 
-- lots of code in fbcon.c
-
-- a bunch of the hooks in fbcon_ops, maybe the remaining hooks could be called
+- a bunch of the hooks in fbcon_ops could be removed or simplified by calling
   directly instead of the function table (with a switch on p->rotate)
 
 - fb_copyarea is unused after this, and can be deleted from all drivers
 
+- after that, fb_copyarea can be deleted from fb_ops in include/linux/fb.h as
+  well as cfb_copyarea
+
 Note that not all acceleration code can be deleted, since clearing and cursor
 support is still accelerated, which might be good candidates for further
 deletion projects.

drivers/video/fbdev/core/bitblit.c

@@ -43,21 +43,6 @@ static void update_attr(u8 *dst, u8 *src, int attribute,
 	}
 }
 
-static void bit_bmove(struct vc_data *vc, struct fb_info *info, int sy,
-		      int sx, int dy, int dx, int height, int width)
-{
-	struct fb_copyarea area;
-
-	area.sx = sx * vc->vc_font.width;
-	area.sy = sy * vc->vc_font.height;
-	area.dx = dx * vc->vc_font.width;
-	area.dy = dy * vc->vc_font.height;
-	area.height = height * vc->vc_font.height;
-	area.width = width * vc->vc_font.width;
-
-	info->fbops->fb_copyarea(info, &area);
-}
-
 static void bit_clear(struct vc_data *vc, struct fb_info *info, int sy,
 		      int sx, int height, int width)
 {
@@ -393,7 +378,6 @@ static int bit_update_start(struct fb_info *info)
 
 void fbcon_set_bitops(struct fbcon_ops *ops)
 {
-	ops->bmove = bit_bmove;
 	ops->clear = bit_clear;
 	ops->putcs = bit_putcs;
 	ops->clear_margins = bit_clear_margins;

drivers/video/fbdev/core/fbcon.h

@@ -29,7 +29,6 @@ struct fbcon_display {
     /* Filled in by the low-level console driver */
     const u_char *fontdata;
     int userfont;                   /* != 0 if fontdata kmalloc()ed */
-    u_short scrollmode;             /* Scroll Method */
     u_short inverse;                /* != 0 text black on white as default */
     short yscroll;                  /* Hardware scrolling */
     int vrows;                      /* number of virtual rows */
@@ -52,8 +51,6 @@ struct fbcon_display {
 };
 
 struct fbcon_ops {
-	void (*bmove)(struct vc_data *vc, struct fb_info *info, int sy,
-		      int sx, int dy, int dx, int height, int width);
 	void (*clear)(struct vc_data *vc, struct fb_info *info, int sy,
 		      int sx, int height, int width);
 	void (*putcs)(struct vc_data *vc, struct fb_info *info,
@@ -152,62 +149,6 @@ static inline int attr_col_ec(int shift, struct vc_data *vc,
 #define attr_bgcol_ec(bgshift, vc, info) attr_col_ec(bgshift, vc, info, 0)
 #define attr_fgcol_ec(fgshift, vc, info) attr_col_ec(fgshift, vc, info, 1)
 
-    /*
-     *  Scroll Method
-     */
-     
-/* 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_MOVE	   0x001
-#define SCROLL_PAN_MOVE	   0x002
-#define SCROLL_WRAP_MOVE   0x003
-#define SCROLL_REDRAW	   0x004
-#define SCROLL_PAN_REDRAW  0x005
-
 #ifdef CONFIG_FB_TILEBLITTING
 extern void fbcon_set_tileops(struct vc_data *vc, struct fb_info *info);
 #endif

drivers/video/fbdev/core/fbcon_ccw.c

@@ -59,31 +59,12 @@ static void ccw_update_attr(u8 *dst, u8 *src, int attribute,
 	}
 }
 
-
-static void ccw_bmove(struct vc_data *vc, struct fb_info *info, int sy,
-		     int sx, int dy, int dx, int height, int width)
-{
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct fb_copyarea area;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
-
-	area.sx = sy * vc->vc_font.height;
-	area.sy = vyres - ((sx + width) * vc->vc_font.width);
-	area.dx = dy * vc->vc_font.height;
-	area.dy = vyres - ((dx + width) * vc->vc_font.width);
-	area.width = height * vc->vc_font.height;
-	area.height  = width * vc->vc_font.width;
-
-	info->fbops->fb_copyarea(info, &area);
-}
-
 static void ccw_clear(struct vc_data *vc, struct fb_info *info, int sy,
 		     int sx, int height, int width)
 {
-	struct fbcon_ops *ops = info->fbcon_par;
 	struct fb_fillrect region;
 	int bgshift = (vc->vc_hi_font_mask) ? 13 : 12;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
 
 	region.color = attr_bgcol_ec(bgshift,vc,info);
 	region.dx = sy * vc->vc_font.height;
@@ -140,7 +121,7 @@ static void ccw_putcs(struct vc_data *vc, struct fb_info *info,
 	u32 cnt, pitch, size;
 	u32 attribute = get_attribute(info, scr_readw(s));
 	u8 *dst, *buf = NULL;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
 
 	if (!ops->fontbuffer)
 		return;
@@ -229,7 +210,7 @@ static void ccw_cursor(struct vc_data *vc, struct fb_info *info, int mode,
 	int attribute, use_sw = vc->vc_cursor_type & CUR_SW;
 	int err = 1, dx, dy;
 	char *src;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
 
 	if (!ops->fontbuffer)
 		return;
@@ -387,7 +368,7 @@ static int ccw_update_start(struct fb_info *info)
 {
 	struct fbcon_ops *ops = info->fbcon_par;
 	u32 yoffset;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
 	int err;
 
 	yoffset = (vyres - info->var.yres) - ops->var.xoffset;
@@ -402,7 +383,6 @@ static int ccw_update_start(struct fb_info *info)
 
 void fbcon_rotate_ccw(struct fbcon_ops *ops)
 {
-	ops->bmove = ccw_bmove;
 	ops->clear = ccw_clear;
 	ops->putcs = ccw_putcs;
 	ops->clear_margins = ccw_clear_margins;

drivers/video/fbdev/core/fbcon_cw.c

@@ -44,31 +44,12 @@ static void cw_update_attr(u8 *dst, u8 *src, int attribute,
 	}
 }
 
-
-static void cw_bmove(struct vc_data *vc, struct fb_info *info, int sy,
-		     int sx, int dy, int dx, int height, int width)
-{
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct fb_copyarea area;
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
-
-	area.sx = vxres - ((sy + height) * vc->vc_font.height);
-	area.sy = sx * vc->vc_font.width;
-	area.dx = vxres - ((dy + height) * vc->vc_font.height);
-	area.dy = dx * vc->vc_font.width;
-	area.width = height * vc->vc_font.height;
-	area.height  = width * vc->vc_font.width;
-
-	info->fbops->fb_copyarea(info, &area);
-}
-
 static void cw_clear(struct vc_data *vc, struct fb_info *info, int sy,
 		     int sx, int height, int width)
 {
-	struct fbcon_ops *ops = info->fbcon_par;
 	struct fb_fillrect region;
 	int bgshift = (vc->vc_hi_font_mask) ? 13 : 12;
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vxres = info->var.xres;
 
 	region.color = attr_bgcol_ec(bgshift,vc,info);
 	region.dx = vxres - ((sy + height) * vc->vc_font.height);
@@ -125,7 +106,7 @@ static void cw_putcs(struct vc_data *vc, struct fb_info *info,
 	u32 cnt, pitch, size;
 	u32 attribute = get_attribute(info, scr_readw(s));
 	u8 *dst, *buf = NULL;
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vxres = info->var.xres;
 
 	if (!ops->fontbuffer)
 		return;
@@ -212,7 +193,7 @@ static void cw_cursor(struct vc_data *vc, struct fb_info *info, int mode,
 	int attribute, use_sw = vc->vc_cursor_type & CUR_SW;
 	int err = 1, dx, dy;
 	char *src;
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vxres = info->var.xres;
 
 	if (!ops->fontbuffer)
 		return;
@@ -369,7 +350,7 @@ static void cw_cursor(struct vc_data *vc, struct fb_info *info, int mode,
 static int cw_update_start(struct fb_info *info)
 {
 	struct fbcon_ops *ops = info->fbcon_par;
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vxres = info->var.xres;
 	u32 xoffset;
 	int err;
 
@@ -385,7 +366,6 @@ static int cw_update_start(struct fb_info *info)
 
 void fbcon_rotate_cw(struct fbcon_ops *ops)
 {
-	ops->bmove = cw_bmove;
 	ops->clear = cw_clear;
 	ops->putcs = cw_putcs;
 	ops->clear_margins = cw_clear_margins;

drivers/video/fbdev/core/fbcon_rotate.h

@@ -11,15 +11,6 @@
 #ifndef _FBCON_ROTATE_H
 #define _FBCON_ROTATE_H
 
-#define GETVYRES(s,i) ({                           \
-        (s == SCROLL_REDRAW || s == SCROLL_MOVE) ? \
-        (i)->var.yres : (i)->var.yres_virtual; })
-
-#define GETVXRES(s,i) ({                           \
-        (s == SCROLL_REDRAW || s == SCROLL_MOVE || !(i)->fix.xpanstep) ? \
-        (i)->var.xres : (i)->var.xres_virtual; })
-
-
 static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
 {
 	u32 tmp = (y * pitch) + x, index = tmp / 8,  bit = tmp % 8;

drivers/video/fbdev/core/fbcon_ud.c

@@ -44,33 +44,13 @@ static void ud_update_attr(u8 *dst, u8 *src, int attribute,
 	}
 }
 
-
-static void ud_bmove(struct vc_data *vc, struct fb_info *info, int sy,
-		     int sx, int dy, int dx, int height, int width)
-{
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct fb_copyarea area;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
-
-	area.sy = vyres - ((sy + height) * vc->vc_font.height);
-	area.sx = vxres - ((sx + width) * vc->vc_font.width);
-	area.dy = vyres - ((dy + height) * vc->vc_font.height);
-	area.dx = vxres - ((dx + width) * vc->vc_font.width);
-	area.height = height * vc->vc_font.height;
-	area.width  = width * vc->vc_font.width;
-
-	info->fbops->fb_copyarea(info, &area);
-}
-
 static void ud_clear(struct vc_data *vc, struct fb_info *info, int sy,
 		     int sx, int height, int width)
 {
-	struct fbcon_ops *ops = info->fbcon_par;
 	struct fb_fillrect region;
 	int bgshift = (vc->vc_hi_font_mask) ? 13 : 12;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
+	u32 vxres = info->var.xres;
 
 	region.color = attr_bgcol_ec(bgshift,vc,info);
 	region.dy = vyres - ((sy + height) * vc->vc_font.height);
@@ -162,8 +142,8 @@ static void ud_putcs(struct vc_data *vc, struct fb_info *info,
 	u32 mod = vc->vc_font.width % 8, cnt, pitch, size;
 	u32 attribute = get_attribute(info, scr_readw(s));
 	u8 *dst, *buf = NULL;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
+	u32 vxres = info->var.xres;
 
 	if (!ops->fontbuffer)
 		return;
@@ -259,8 +239,8 @@ static void ud_cursor(struct vc_data *vc, struct fb_info *info, int mode,
 	int attribute, use_sw = vc->vc_cursor_type & CUR_SW;
 	int err = 1, dx, dy;
 	char *src;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
+	u32 vxres = info->var.xres;
 
 	if (!ops->fontbuffer)
 		return;
@@ -410,8 +390,8 @@ static int ud_update_start(struct fb_info *info)
 {
 	struct fbcon_ops *ops = info->fbcon_par;
 	int xoffset, yoffset;
-	u32 vyres = GETVYRES(ops->p->scrollmode, info);
-	u32 vxres = GETVXRES(ops->p->scrollmode, info);
+	u32 vyres = info->var.yres;
+	u32 vxres = info->var.xres;
 	int err;
 
 	xoffset = vxres - info->var.xres - ops->var.xoffset;
@@ -429,7 +409,6 @@ static int ud_update_start(struct fb_info *info)
 
 void fbcon_rotate_ud(struct fbcon_ops *ops)
 {
-	ops->bmove = ud_bmove;
 	ops->clear = ud_clear;
 	ops->putcs = ud_putcs;
 	ops->clear_margins = ud_clear_margins;

drivers/video/fbdev/core/tileblit.c

@@ -16,21 +16,6 @@
 #include <asm/types.h>
 #include "fbcon.h"
 
-static void tile_bmove(struct vc_data *vc, struct fb_info *info, int sy,
-		       int sx, int dy, int dx, int height, int width)
-{
-	struct fb_tilearea area;
-
-	area.sx = sx;
-	area.sy = sy;
-	area.dx = dx;
-	area.dy = dy;
-	area.height = height;
-	area.width = width;
-
-	info->tileops->fb_tilecopy(info, &area);
-}
-
 static void tile_clear(struct vc_data *vc, struct fb_info *info, int sy,
 		       int sx, int height, int width)
 {
@@ -133,7 +118,6 @@ void fbcon_set_tileops(struct vc_data *vc, struct fb_info *info)
 	struct fb_tilemap map;
 	struct fbcon_ops *ops = info->fbcon_par;
 
-	ops->bmove = tile_bmove;
 	ops->clear = tile_clear;
 	ops->putcs = tile_putcs;
 	ops->clear_margins = tile_clear_margins;

drivers/video/fbdev/skeletonfb.c

@@ -505,15 +505,15 @@ void xxxfb_fillrect(struct fb_info *p, const struct fb_fillrect *region)
 }
 
 /**
- *      xxxfb_copyarea - REQUIRED function. Can use generic routines if
- *                       non acclerated hardware and packed pixel based.
+ *      xxxfb_copyarea - OBSOLETE function.
  *                       Copies one area of the screen to another area.
+ *                       Will be deleted in a future version
  *
  *      @info: frame buffer structure that represents a single frame buffer
  *      @area: Structure providing the data to copy the framebuffer contents
  *	       from one region to another.
  *
- *      This drawing operation copies a rectangular area from one area of the
+ *      This drawing operation copied a rectangular area from one area of the
  *	screen to another area.
  */
 void xxxfb_copyarea(struct fb_info *p, const struct fb_copyarea *area) 
@@ -645,9 +645,9 @@ static const struct fb_ops xxxfb_ops = {
 	.fb_setcolreg	= xxxfb_setcolreg,
 	.fb_blank	= xxxfb_blank,
 	.fb_pan_display	= xxxfb_pan_display,
-	.fb_fillrect	= xxxfb_fillrect, 	/* Needed !!! */
-	.fb_copyarea	= xxxfb_copyarea,	/* Needed !!! */
-	.fb_imageblit	= xxxfb_imageblit,	/* Needed !!! */
+	.fb_fillrect	= xxxfb_fillrect,	/* Needed !!!   */
+	.fb_copyarea	= xxxfb_copyarea,	/* Obsolete     */
+	.fb_imageblit	= xxxfb_imageblit,	/* Needed !!!   */
 	.fb_cursor	= xxxfb_cursor,		/* Optional !!! */
 	.fb_sync	= xxxfb_sync,
 	.fb_ioctl	= xxxfb_ioctl,

include/linux/fb.h

@@ -262,7 +262,7 @@ struct fb_ops {
 
 	/* Draws a rectangle */
 	void (*fb_fillrect) (struct fb_info *info, const struct fb_fillrect *rect);
-	/* Copy data from area to another */
+	/* Copy data from area to another. Obsolete. */
 	void (*fb_copyarea) (struct fb_info *info, const struct fb_copyarea *region);
 	/* Draws a image to the display */
 	void (*fb_imageblit) (struct fb_info *info, const struct fb_image *image);