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fbdev: Add Tile Blitting support

PATCH In review Antonino A. Daplas 3 participants 5 messages Sep 9, 2004 – Sep 10, 2004

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Antonino A. Daplas

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PATCH 7/7 fbdev: Add Tile Blitting support

Hopefully, this patch fixes one last major regression for one particular driver, namely matroxfb. This drier has 2 versions, one for the kernel and another as a '2.4 backport' patch.

This patch adds a tileblitting extension to fbcon. This extension, in summary, is basically a forward-port of the 2.4 fbdev/fbcon framework to 2.6 but without the fbcon dependency. Tile blitting is similar to bitblit, except that the basic unit is a tile (a bitmap of x-by-y dimensions). The display, instead of being described in terms of pixels and scanlines, are described as a region further subdivided into rectangular sections. In fbcon parlance, a tile is a character.

Besides a possible fix for matroxfb, tileblitting can be advantageous for hardware that supports some kind of fontcaching mechanism. Also, in the unlikely chance that the console begins supporting multicolored fonts, tileblitting is probably more optimal than bitblitting because bitblitting will need to push more data through the bus.

To enable support for this extension, a driver needs to:

- enable CONFIG_FB_TILEBLITTING
- set FBINFO_MISC_TILEBLITTING in info->flags
- set the required function pointers in struct fb_tileops. The required operations are:

- void (*fb_settile)(struct fb_info *info, struct fb_tilemap *map);

tells driver about the tile characteristics (dimensions, bitdepth) and about the tilemap which is an array of bitmaps: display->fontdata

- void (*fb_tilecopy)(struct fb_info *info, struct fb_tilearea *area);

move a rectangular section of tiles (bmove)

- void (*fb_tilefill)(struct fb_info *info, struct fb_tilerect *rect);

fill a rectangular section with a tile (clear)

- void (*fb_tileblit)(struct fb_info *info, struct fb_tileblit *blit);

copy an array of tiles to a rectangular section (putcs)

- void (*fb_tilecursor)(struct fb_info *info, struct fb_tilecursor *cursor);

cursor function

Changes:

Addition of this extension necessitates cleanup of fbcon.c. The basic drawing functions in fbcon are bmove, clear, putcs and cursor (the fbcon_* set). The fbcon_* set are just wrappers to accel_* set. However, usage is not consistent, some functions call the fbcon_* set, others call the accel_* set.

With this patch, a new fbcon-specific structure (struct fbcon_ops) is created. Depending on the setting of the hardware, this struct contains pointers to either the tileblitting set or the bitblitting set (formerly the accel_* set). The tileblitting set is new in this patch.

The vast majority of functions in fbcon will need to only call the fbcon_* set. In turn, it calls functions in struct fbcon_ops. Knowledge of the blitting type is not required.

The accel_* set is renamed to bit_* and is moved into a separate file, bitblit.c. The tile blitting set is in tileblit.c.

In my case at least, the cleanup did produce an unexpected but beneficial side effect, a little more speedup. Not much, < 5%.

Petr, if you have comments, suggestions, or you think this is a bad idea, let me know.

Signed-off-by Antonino Daplas <[email protected]>

---

 drivers/video/Kconfig            |   18 +
 drivers/video/console/Makefile   |    3
 drivers/video/console/bitblit.c  |  370 ++++++++++++++++++++++
 drivers/video/console/fbcon.c    |  637 +++++++++++----------------------------
 drivers/video/console/fbcon.h    |   26 +
 drivers/video/console/tileblit.c |  146 ++++++++
 drivers/video/fbmem.c            |    4
 include/linux/fb.h               |   83 +++++
 8 files changed, 842 insertions(+), 445 deletions(-)
drivers/video/console/bitblit.c +370 -0
diff -uprN linux-2.6.9-rc1-mm4-orig/drivers/video/console/bitblit.c linux-2.6.9-rc1-mm4/drivers/video/console/bitblit.c
@@ -0,0 +1,370 @@
+/*
+ *  linux/drivers/video/console/bitblit.c -- BitBlitting Operation
+ *
+ *  Originally from the 'accel_*' routines in drivers/video/console/fbcon.c
+ *
+ *      Copyright (C) 2004 Antonino Daplas <adaplas @pol.net>
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License.  See the file COPYING in the main directory of this archive for
+ *  more details.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fb.h>
+#include <linux/vt_kern.h>
+#include <linux/console.h>
+#include <asm/types.h>
+#include "fbcon.h"
+
+/*
+ * Accelerated handlers.
+ */
+#define FBCON_ATTRIBUTE_UNDERLINE 1
+#define FBCON_ATTRIBUTE_REVERSE   2
+#define FBCON_ATTRIBUTE_BOLD      4
+
+static inline int real_y(struct display *p, int ypos)
+{
+	int rows = p->vrows;
+
+	ypos += p->yscroll;
+	return ypos < rows ? ypos : ypos - rows;
+}
+
+
+static inline int get_attribute(struct fb_info *info, u16 c)
+{
+	int attribute = 0;
+
+	if (fb_get_color_depth(info) == 1) {
+		if (attr_underline(c))
+			attribute |= FBCON_ATTRIBUTE_UNDERLINE;
+		if (attr_reverse(c))
+			attribute |= FBCON_ATTRIBUTE_REVERSE;
+		if (attr_bold(c))
+			attribute |= FBCON_ATTRIBUTE_BOLD;
+	}
+
+	return attribute;
+}
+
+static inline void update_attr(u8 *dst, u8 *src, int attribute,
+			       struct vc_data *vc)
+{
+	int i, offset = (vc->vc_font.height < 10) ? 1 : 2;
+	int width = (vc->vc_font.width + 7) >> 3;
+	unsigned int cellsize = vc->vc_font.height * width;
+	u8 c;
+
+	offset = cellsize - (offset * width);
+	for (i = 0; i < cellsize; i++) {
+		c = src[i];
+		if (attribute & FBCON_ATTRIBUTE_UNDERLINE && i >= offset)
+			c = 0xff;
+		if (attribute & FBCON_ATTRIBUTE_BOLD)
+			c |= c >> 1;
+		if (attribute & FBCON_ATTRIBUTE_REVERSE)
+			c = ~c;
+		dst[i] = c;
+	}
+}
+
+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)
+{
+	int bgshift = (vc->vc_hi_font_mask) ? 13 : 12;
+	struct fb_fillrect region;
+
+	region.color = attr_bgcol_ec(bgshift, vc);
+	region.dx = sx * vc->vc_font.width;
+	region.dy = sy * vc->vc_font.height;
+	region.width = width * vc->vc_font.width;
+	region.height = height * vc->vc_font.height;
+	region.rop = ROP_COPY;
+
+	info->fbops->fb_fillrect(info, &region);
+}
+
+static void bit_putcs(struct vc_data *vc, struct fb_info *info,
+		      const unsigned short *s, int count, int yy, int xx,
+		      int fg, int bg)
+{
+	void (*move_unaligned)(struct fb_info *info, struct fb_pixmap *buf,
+			       u8 *dst, u32 d_pitch, u8 *src, u32 idx,
+			       u32 height, u32 shift_high, u32 shift_low,
+			       u32 mod);
+	void (*move_aligned)(struct fb_info *info, struct fb_pixmap *buf,
+			     u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch,
+			     u32 height);
+	unsigned short charmask = vc->vc_hi_font_mask ? 0x1ff : 0xff;
+	unsigned int width = (vc->vc_font.width + 7) >> 3;
+	unsigned int cellsize = vc->vc_font.height * width;
+	unsigned int maxcnt = info->pixmap.size/cellsize;
+	unsigned int scan_align = info->pixmap.scan_align - 1;
+	unsigned int buf_align = info->pixmap.buf_align - 1;
+	unsigned int shift_low = 0, mod = vc->vc_font.width % 8;
+	unsigned int shift_high = 8, pitch, cnt, size, k;
+	unsigned int idx = vc->vc_font.width >> 3;
+	unsigned int attribute = get_attribute(info, scr_readw(s));
+	struct fb_image image;
+	u8 *src, *dst, *buf = NULL;
+
+	if (attribute) {
+		buf = kmalloc(cellsize, GFP_KERNEL);
+		if (!buf)
+			return;
+	}
+
+	image.fg_color = fg;
+	image.bg_color = bg;
+
+	image.dx = xx * vc->vc_font.width;
+	image.dy = yy * vc->vc_font.height;
+	image.height = vc->vc_font.height;
+	image.depth = 1;
+
+	if (info->pixmap.outbuf && info->pixmap.inbuf) {
+		move_aligned = fb_iomove_buf_aligned;
+		move_unaligned = fb_iomove_buf_unaligned;
+	} else {
+		move_aligned = fb_sysmove_buf_aligned;
+		move_unaligned = fb_sysmove_buf_unaligned;
+	}
+	while (count) {
+		if (count > maxcnt)
+			cnt = k = maxcnt;
+		else
+			cnt = k = count;
+
+		image.width = vc->vc_font.width * cnt;
+		pitch = ((image.width + 7) >> 3) + scan_align;
+		pitch &= ~scan_align;
+		size = pitch * image.height + buf_align;
+		size &= ~buf_align;
+		dst = fb_get_buffer_offset(info, &info->pixmap, size);
+		image.data = dst;
+		if (mod) {
+			while (k--) {
+				src = vc->vc_font.data + (scr_readw(s++)&
+							  charmask)*cellsize;
+
+				if (attribute) {
+					update_attr(buf, src, attribute, vc);
+					src = buf;
+				}
+
+				move_unaligned(info, &info->pixmap, dst, pitch,
+					       src, idx, image.height,
+					       shift_high, shift_low, mod);
+				shift_low += mod;
+				dst += (shift_low >= 8) ? width : width - 1;
+				shift_low &= 7;
+				shift_high = 8 - shift_low;
+			}
+		} else {
+			while (k--) {
+				src = vc->vc_font.data + (scr_readw(s++)&
+							  charmask)*cellsize;
+
+				if (attribute) {
+					update_attr(buf, src, attribute, vc);
+					src = buf;
+				}
+
+				move_aligned(info, &info->pixmap, dst, pitch,
+					     src, idx, image.height);
+				dst += width;
+			}
+		}
+		info->fbops->fb_imageblit(info, &image);
+		image.dx += cnt * vc->vc_font.width;
+		count -= cnt;
+	}
+
+	if (buf)
+		kfree(buf);
+}
+
+static void bit_clear_margins(struct vc_data *vc, struct fb_info *info,
+			      int bottom_only)
+{
+	int bgshift = (vc->vc_hi_font_mask) ? 13 : 12;
+	unsigned int cw = vc->vc_font.width;
+	unsigned int ch = vc->vc_font.height;
+	unsigned int rw = info->var.xres - (vc->vc_cols*cw);
+	unsigned int bh = info->var.yres - (vc->vc_rows*ch);
+	unsigned int rs = info->var.xres - rw;
+	unsigned int bs = info->var.yres - bh;
+	struct fb_fillrect region;
+
+	region.color = attr_bgcol_ec(bgshift, vc);
+	region.rop = ROP_COPY;
+
+	if (rw && !bottom_only) {
+		region.dx = info->var.xoffset + rs;
+		region.dy = 0;
+		region.width = rw;
+		region.height = info->var.yres_virtual;
+		info->fbops->fb_fillrect(info, &region);
+	}
+
+	if (bh) {
+		region.dx = info->var.xoffset;
+		region.dy = info->var.yoffset + bs;
+		region.width = rs;
+		region.height = bh;
+		info->fbops->fb_fillrect(info, &region);
+	}
+}
+
+static void bit_cursor(struct vc_data *vc, struct fb_info *info,
+		       struct display *p, int mode, int fg, int bg)
+{
+	struct fb_cursor cursor;
+	unsigned short charmask = vc->vc_hi_font_mask ? 0x1ff : 0xff;
+	int w = (vc->vc_font.width + 7) >> 3, c;
+	int y = real_y(p, vc->vc_y);
+	int attribute;
+	char *src;
+
+ 	c = scr_readw((u16 *) vc->vc_pos);
+	attribute = get_attribute(info, c);
+	src = vc->vc_font.data + ((c & charmask) * (w * vc->vc_font.height));
+	if (attribute) {
+		u8 *dst;
+
+		dst = kmalloc(w * vc->vc_font.height, GFP_ATOMIC);
+		if (!dst)
+			return;
+		if (info->cursor.data)
+			kfree(info->cursor.data);
+		info->cursor.data = dst;
+		update_attr(dst, src, attribute, vc);
+		src = dst;
+	}
+
+	cursor.image.data = src;
+	cursor.set = FB_CUR_SETCUR;
+	cursor.image.depth = 1;
+
+	switch (mode) {
+	case CM_ERASE:
+		if (info->cursor.rop == ROP_XOR) {
+			info->cursor.enable = 0;
+			info->cursor.rop = ROP_COPY;
+			info->fbops->fb_cursor(info, &cursor);
+		}
+		break;
+	case CM_MOVE:
+	case CM_DRAW:
+		info->cursor.enable = 1;
+        	info->cursor.rop = ROP_XOR;
+
+		if (info->cursor.image.fg_color != fg ||
+		    info->cursor.image.bg_color != bg) {
+			cursor.image.fg_color = fg;
+			cursor.image.bg_color = bg;
+			cursor.set |= FB_CUR_SETCMAP;
+		}
+
+		if ((info->cursor.image.dx != (vc->vc_font.width * vc->vc_x)) ||
+		    (info->cursor.image.dy != (vc->vc_font.height * y))) {
+			cursor.image.dx = vc->vc_font.width * vc->vc_x;
+			cursor.image.dy = vc->vc_font.height * y;
+			cursor.set |= FB_CUR_SETPOS;
+		}
+
+		if (info->cursor.image.height != vc->vc_font.height ||
+		    info->cursor.image.width != vc->vc_font.width) {
+			cursor.image.height = vc->vc_font.height;
+			cursor.image.width = vc->vc_font.width;
+			cursor.set |= FB_CUR_SETSIZE;
+		}
+
+		if (info->cursor.hot.x || info->cursor.hot.y) {
+			cursor.hot.x = cursor.hot.y = 0;
+			cursor.set |= FB_CUR_SETHOT;
+		}
+
+		if ((cursor.set & FB_CUR_SETSIZE) ||
+		    ((vc->vc_cursor_type & 0x0f) != p->cursor_shape)
+		    || info->cursor.mask == NULL) {
+			char *mask = kmalloc(w*vc->vc_font.height, GFP_ATOMIC);
+			int cur_height, size, i = 0;
+			u8 msk = 0xff;
+
+			if (!mask)
+				return;
+
+			if (info->cursor.mask)
+				kfree(info->cursor.mask);
+			info->cursor.mask = mask;
+			p->cursor_shape = vc->vc_cursor_type & 0x0f;
+			cursor.set |= FB_CUR_SETSHAPE;
+
+			switch (vc->vc_cursor_type & 0x0f) {
+			case CUR_NONE:
+				cur_height = 0;
+				break;
+			case CUR_UNDERLINE:
+				cur_height = (vc->vc_font.height < 10) ? 1 : 2;
+				break;
+			case CUR_LOWER_THIRD:
+				cur_height = vc->vc_font.height/3;
+				break;
+			case CUR_LOWER_HALF:
+				cur_height = vc->vc_font.height >> 1;
+				break;
+			case CUR_TWO_THIRDS:
+				cur_height = (vc->vc_font.height << 1)/3;
+				break;
+			case CUR_BLOCK:
+			default:
+				cur_height = vc->vc_font.height;
+				break;
+			}
+			size = (vc->vc_font.height - cur_height) * w;
+			while (size--)
+				mask[i++] = ~msk;
+			size = cur_height * w;
+			while (size--)
+				mask[i++] = msk;
+		}
+		info->fbops->fb_cursor(info, &cursor);
+		break;
+	}
+}
+
+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;
+	ops->cursor = bit_cursor;
+}
+
+EXPORT_SYMBOL(fbcon_set_bitops);
+
+MODULE_AUTHOR("Antonino Daplas <[email protected]>");
+MODULE_DESCRIPTION("Bit Blitting Operation");
+MODULE_LICENSE("GPL");
+
drivers/video/console/fbcon.c +195 -442

987 lines not on this page · raw message

drivers/video/console/fbcon.h +25 -1
diff -uprN linux-2.6.9-rc1-mm4-orig/drivers/video/console/fbcon.h linux-2.6.9-rc1-mm4/drivers/video/console/fbcon.h
@@ -48,6 +48,19 @@ struct display {
     struct fb_videomode *mode;
 };
 
+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,
+		      const unsigned short *s, int count, int yy, int xx,
+		      int fg, int bg);
+	void (*clear_margins)(struct vc_data *vc, struct fb_info *info,
+			      int bottom_only);
+	void (*cursor)(struct vc_data *vc, struct fb_info *info,
+		       struct display *p, int mode, int fg, int bg);
+};
     /*
      *  Attribute Decoding
      */

@@ -72,6 +85,13 @@ struct display {
 #define attr_blink(s) \
 	((s) & 0x8000)
 	
+/* Font */
+#define REFCOUNT(fd)	(((int *)(fd))[-1])
+#define FNTSIZE(fd)	(((int *)(fd))[-2])
+#define FNTCHARCNT(fd)	(((int *)(fd))[-3])
+#define FNTSUM(fd)	(((int *)(fd))[-4])
+#define FONT_EXTRA_WORDS 4
+
     /*
      *  Scroll Method
      */

@@ -129,5 +149,9 @@ struct display {
 #define SCROLL_PAN_REDRAW  0x005
 
 extern int fb_console_init(void);
-
+#ifdef CONFIG_FB_TILEBLITTING
+extern void fbcon_set_tileops(struct vc_data *vc, struct fb_info *info,
+			      struct display *p, struct fbcon_ops *ops);
+#endif
+extern void fbcon_set_bitops(struct fbcon_ops *ops);
 #endif /* _VIDEO_FBCON_H */
drivers/video/console/Makefile +2 -1
diff -uprN linux-2.6.9-rc1-mm4-orig/drivers/video/console/Makefile linux-2.6.9-rc1-mm4/drivers/video/console/Makefile
@@ -24,7 +24,8 @@ obj-$(CONFIG_PROM_CONSOLE)        += pro
 obj-$(CONFIG_STI_CONSOLE)         += sticon.o sticore.o
 obj-$(CONFIG_VGA_CONSOLE)         += vgacon.o
 obj-$(CONFIG_MDA_CONSOLE)         += mdacon.o
-obj-$(CONFIG_FRAMEBUFFER_CONSOLE) += fbcon.o font.o
+obj-$(CONFIG_FRAMEBUFFER_CONSOLE) += fbcon.o bitblit.o font.o
+obj-$(CONFIG_FB_TILEBLITTING)     += tileblit.o
 
 obj-$(CONFIG_FB_STI)              += sticore.o
drivers/video/console/tileblit.c +146 -0

146 lines not on this page · raw message

drivers/video/fbmem.c +4 -0
diff -uprN linux-2.6.9-rc1-mm4-orig/drivers/video/fbmem.c linux-2.6.9-rc1-mm4/drivers/video/fbmem.c
@@ -368,6 +368,9 @@ int fb_prepare_logo(struct fb_info *info
 
 	memset(&fb_logo, 0, sizeof(struct logo_data));
 
+	if (info->flags & FBINFO_MISC_TILEBLITTING)
+		return 0;
+
 	if (info->fix.visual == FB_VISUAL_DIRECTCOLOR) {
 		depth = info->var.blue.length;
 		if (info->var.red.length < depth)

@@ -669,6 +672,7 @@ fb_cursor(struct fb_info *info, struct f
 	cursor.image.cmap.blue = info->cursor.image.cmap.blue;
 	cursor.image.cmap.transp = info->cursor.image.cmap.transp;
 	cursor.data = NULL;
+	cursor.flash = 0;
 
 	if (cursor.set & FB_CUR_SETCUR)
 		info->cursor.enable = 1;
drivers/video/Kconfig +18 -0
diff -uprN linux-2.6.9-rc1-mm4-orig/drivers/video/Kconfig linux-2.6.9-rc1-mm4/drivers/video/Kconfig
@@ -49,6 +49,24 @@ config FB_MODE_HELPERS
 	  your driver does not take advantage of this feature, choosing Y will
 	  just increase the kernel size by about 5K.
 
+config FB_TILEBLITTING
+       bool "Enable Tile Blitting Support"
+       depends on FB
+       default n
+       ---help---
+         This enables tile blitting.  Tile blitting is a drawing technique
+	 where the screen is divided into rectangular sections (tiles), whereas
+	 the standard blitting divides the screen into pixels. Because the
+	 default drawing element is a tile, drawing functions will be passed
+	 parameters in terms of number of tiles instead of number of pixels.
+	 For example, to draw a single character, instead of using bitmaps,
+	 an index to an array of bitmaps will be used.  To clear or move a
+	 rectangular section of a screen, the rectangle willbe described in
+	 terms of number of tiles in the x- and y-axis.
+
+	 This is particularly important to one driver, the matroxfb.  If
+	 unsure, say N.
+
 config FB_CIRRUS
 	tristate "Cirrus Logic support"
 	depends on FB && (ZORRO || PCI)
include/linux/fb.h +82 -1

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#1 lore raw
Quoted 6 lines · Antonino A. Daplas

In my case at least, the cleanup did produce an unexpected but beneficial side effect, a little more speedup. Not much, < 5%.

Petr, if you have comments, suggestions, or you think this is a bad idea, let me know.

It looks like good idea to me. Though I still do not see benefits 2.6.x fbcon provides over 2.4.x.

BTW, there is still bad bug with software scrollback and multihead (it is here since I remember): redraw_screen sets redraw to 0 when old_console == new_console, but fbcon uses con_switch() method for deciding whether software scrollback should be reinitialized or not. As software scrollback is per-system and not per-fbdev thing, this has rather nasty consequences - when both fbdevs have different xres, console user can crash system (con2fb /dev/fb1 /dev/tty11; set xres fb0 != xres fb1; chvt 11; chvt 10; chvt 11; hit alt-shift-pgup or force vt11 to scroll; crash, some kernel data structures were overwritten with 0x0720...).
Petr Vandrovec

author
#2 lore raw
Quoted 9 lines · Petr Vandrovec
Quoted 5 lines · Antonino A. Daplas

In my case at least, the cleanup did produce an unexpected but beneficial side effect, a little more speedup. Not much, < 5%.

Petr, if you have comments, suggestions, or you think this is a bad idea, let me know.

It looks like good idea to me. Though I still do not see benefits 2.6.x fbcon provides over 2.4.x.

Too late for that :-). Personally, minus the stability and bugs, I prefer 2.6 over 2.4.

Quoted 11 lines

BTW, there is still bad bug with software scrollback and multihead (it is here since I remember): redraw_screen sets redraw to 0 when old_console == new_console, but fbcon uses con_switch() method for deciding whether software scrollback should be reinitialized or not. As software scrollback is per-system and not per-fbdev thing, this has rather nasty consequences - when both fbdevs have different xres, console user can crash system (con2fb /dev/fb1 /dev/tty11; set xres fb0 != xres fb1; chvt 11; chvt 10; chvt 11; hit alt-shift-pgup or force vt11 to scroll; crash, some kernel data structures were overwritten with 0x0720...).

I just tried it now, but can't elicit a crash (2.6.9-rc1-mm4 + my patches). I'll try to examine this in more detail this weekend.

Tony

#3 lore raw
In reply to Antonino A. Daplas
Quoted 9 lines · Antonino A. Daplas
drivers/video/Kconfig +3 -0
@@ -49,6 +49,24 @@ config FB_MODE_HELPERS
 	  your driver does not take advantage of this feature, choosing Y will
 	  just increase the kernel size by about 5K.
 
+config FB_TILEBLITTING
+       bool "Enable Tile Blitting Support"
+       depends on FB

drivers/video/Kconfig config FB_MODE_HELPERS · line 64

Quoted 10 lines
drivers/video/Kconfig +10 -0
+       default n
+       ---help---
+         This enables tile blitting.  Tile blitting is a drawing technique
+	 where the screen is divided into rectangular sections (tiles), whereas
+	 the standard blitting divides the screen into pixels. Because the
+	 default drawing element is a tile, drawing functions will be passed
+	 parameters in terms of number of tiles instead of number of pixels.
+	 For example, to draw a single character, instead of using bitmaps,
+	 an index to an array of bitmaps will be used.  To clear or move a
+	 rectangular section of a screen, the rectangle willbe described in

                                                        ^^^^^^
							will be

drivers/video/Kconfig config FB_MODE_HELPERS · line 67

Quoted 3 lines
drivers/video/Kconfig +3 -0
+	 terms of number of tiles in the x- and y-axis.
+
+	 This is particularly important to one driver, the matroxfb.  If

                                                       ^^^^^^^^^^^^
						       matroxfb?

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

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author
#4 lore raw
Quoted 6 lines · Geert Uytterhoeven
Quoted 2 lines

move a + rectangular section of a screen, the rectangle willbe described
in

                                                        ^^^^^^
							will be
Quoted 7 lines

drivers/video/Kconfig config FB_MODE_HELPERS · line 67

Quoted 3 lines
drivers/video/Kconfig +3 -0
+	 terms of number of tiles in the x- and y-axis.
+
+	 This is particularly important to one driver, the matroxfb.  If

                                                       ^^^^^^^^^^^^
						       matroxfb?

Which proves that documentation is the last thing I check :-)

Thanks.

Tony