[PATCH] Fix VT mode change vs. fbcon

[Benjamin Herrenschmidt]

Hi Linus !

This patch implements what we discussed earlier to fix the
switch bewteen KD_GRAPHICS and KD_TEXT.

It has been tested for a few days now and appear to resolve
the problem for affected users.

James: I know you have some objections, I don't fully agree
with them, and I want that in asap now, that bug has been
plaguing fbdev since the very beginning and it's time to get
rid of that and my corresponding todolist entry. You are
welcome to propose a patch on top of this one if you feel
you can make things cleaner. The approach of adding a parameter
to con_blank() is Linus idea btw :)

I didn't add a separate function as that would have made the
butchering of drivers/char/vt beyond what I want to deal with
in 2.6.

Ben.

===== drivers/char/vt.c 1.61 vs edited =====
--- 1.61/drivers/char/vt.c	Thu Feb 19 14:43:03 2004
+++ edited/drivers/char/vt.c	Fri Feb 27 17:27:09 2004
@@ -2743,12 +2743,12 @@
      *  Called only if powerdown features are allowed.
      */
     switch (vesa_blank_mode) {
-	case VESA_NO_BLANKING:
-	    c->vc_sw->con_blank(c, VESA_VSYNC_SUSPEND+1);
+    case VESA_NO_BLANKING:
+	    c->vc_sw->con_blank(c, VESA_VSYNC_SUSPEND+1, 0);
 	    break;
-	case VESA_VSYNC_SUSPEND:
-	case VESA_HSYNC_SUSPEND:
-	    c->vc_sw->con_blank(c, VESA_POWERDOWN+1);
+    case VESA_VSYNC_SUSPEND:
+    case VESA_HSYNC_SUSPEND:
+	    c->vc_sw->con_blank(c, VESA_POWERDOWN+1, 0);
 	    break;
     }
 }
@@ -2776,7 +2776,7 @@
 	if (entering_gfx) {
 		hide_cursor(currcons);
 		save_screen(currcons);
-		sw->con_blank(vc_cons[currcons].d, -1);
+		sw->con_blank(vc_cons[currcons].d, -1, 1);
 		console_blanked = fg_console + 1;
 		set_origin(currcons);
 		return;
@@ -2794,7 +2794,7 @@
 
 	save_screen(currcons);
 	/* In case we need to reset origin, blanking hook returns 1 */
-	i = sw->con_blank(vc_cons[currcons].d, 1);
+	i = sw->con_blank(vc_cons[currcons].d, 1, 0);
 	console_blanked = fg_console + 1;
 	if (i)
 		set_origin(currcons);
@@ -2808,14 +2808,14 @@
 	}
 
     	if (vesa_blank_mode)
-		sw->con_blank(vc_cons[currcons].d, vesa_blank_mode + 1);
+		sw->con_blank(vc_cons[currcons].d, vesa_blank_mode + 1, 0);
 }
 
 
 /*
  * Called by timer as well as from vt_console_driver
  */
-void unblank_screen(void)
+void do_unblank_screen(int leaving_gfx)
 {
 	int currcons;
 
@@ -2839,13 +2839,24 @@
 	}
 
 	console_blanked = 0;
-	if (sw->con_blank(vc_cons[currcons].d, 0))
+	if (sw->con_blank(vc_cons[currcons].d, 0, leaving_gfx))
 		/* Low-level driver cannot restore -> do it ourselves */
 		update_screen(fg_console);
 	if (console_blank_hook)
 		console_blank_hook(0);
 	set_palette(currcons);
 	set_cursor(fg_console);
+}
+
+/*
+ * This is called by the outside world to cause a forced unblank, mostly for
+ * oopses. Currently, I just call do_unblank_screen(0), but we could eventually
+ * call it with 1 as an argument and so force a mode restore... that may kill
+ * X or at least garbage the screen but would also make the Oops visible...
+ */
+void unblank_screen(void)
+{
+	do_unblank_screen(0);
 }
 
 /*
===== drivers/char/vt_ioctl.c 1.34 vs edited =====
--- 1.34/drivers/char/vt_ioctl.c	Wed Feb 25 21:31:13 2004
+++ edited/drivers/char/vt_ioctl.c	Fri Feb 27 17:27:21 2004
@@ -497,7 +497,7 @@
 		 */
 		acquire_console_sem();
 		if (arg == KD_TEXT)
-			unblank_screen();
+			do_unblank_screen(1);
 		else
 			do_blank_screen(1);
 		release_console_sem();
@@ -1103,7 +1103,7 @@
 	if (old_vc_mode != vt_cons[new_console]->vc_mode)
 	{
 		if (vt_cons[new_console]->vc_mode == KD_TEXT)
-			unblank_screen();
+			do_unblank_screen(1);
 		else
 			do_blank_screen(1);
 	}
@@ -1138,7 +1138,7 @@
 			if (old_vc_mode != vt_cons[new_console]->vc_mode)
 			{
 				if (vt_cons[new_console]->vc_mode == KD_TEXT)
-					unblank_screen();
+					do_unblank_screen(1);
 				else
 					do_blank_screen(1);
 			}
===== drivers/video/fbmem.c 1.90 vs edited =====
--- 1.90/drivers/video/fbmem.c	Mon Feb 16 23:42:15 2004
+++ edited/drivers/video/fbmem.c	Fri Feb 27 17:25:21 2004
@@ -943,7 +943,8 @@
 {
 	int err;
 
-	if (memcmp(&info->var, var, sizeof(struct fb_var_screeninfo))) {
+	if ((var->activate & FB_ACTIVATE_FORCE) ||
+	    memcmp(&info->var, var, sizeof(struct fb_var_screeninfo))) {
 		if (!info->fbops->fb_check_var) {
 			*var = info->var;
 			return 0;
===== drivers/video/console/fbcon.c 1.109 vs edited =====
--- 1.109/drivers/video/console/fbcon.c	Mon Feb 16 05:22:04 2004
+++ edited/drivers/video/console/fbcon.c	Fri Feb 27 17:47:24 2004
@@ -159,7 +159,7 @@
 static void fbcon_bmove(struct vc_data *vc, int sy, int sx, int dy, int dx,
 			int height, int width);
 static int fbcon_switch(struct vc_data *vc);
-static int fbcon_blank(struct vc_data *vc, int blank);
+static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch);
 static int fbcon_font_op(struct vc_data *vc, struct console_font_op *op);
 static int fbcon_set_palette(struct vc_data *vc, unsigned char *table);
 static int fbcon_scrolldelta(struct vc_data *vc, int lines);
@@ -1696,14 +1696,23 @@
 	return 1;
 }
 
-static int fbcon_blank(struct vc_data *vc, int blank)
+static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
 {
 	unsigned short charmask = vc->vc_hi_font_mask ? 0x1ff : 0xff;
 	struct fb_info *info = registered_fb[(int) con2fb_map[vc->vc_num]];
 	struct display *p = &fb_display[vc->vc_num];
 
-	if (blank < 0)		/* Entering graphics mode */
-		return 0;
+	if (mode_switch) {
+		struct fb_info *info = registered_fb[(int) con2fb_map[vc->vc_num]];
+		struct fb_var_screeninfo var = info->var;
+
+		if (blank) {
+			fbcon_cursor(vc, CM_ERASE);
+			return 0;
+		}
+		var.activate = FB_ACTIVATE_NOW | FB_ACTIVATE_FORCE;
+		fb_set_var(info, &var);
+	}
 
 	fbcon_cursor(vc, blank ? CM_ERASE : CM_DRAW);
 
===== drivers/video/console/promcon.c 1.9 vs edited =====
--- 1.9/drivers/video/console/promcon.c	Wed Dec 11 14:49:09 2002
+++ edited/drivers/video/console/promcon.c	Fri Feb 27 17:24:34 2004
@@ -463,7 +463,7 @@
 }
         
 static int
-promcon_blank(struct vc_data *conp, int blank)
+promcon_blank(struct vc_data *conp, int blank, int mode_switch)
 {
 	if (blank) {
 		promcon_puts("\033[H\033[J\033[7m \033[m\b", 15);
===== drivers/video/console/sticon.c 1.8 vs edited =====
--- 1.8/drivers/video/console/sticon.c	Wed Jan  8 11:45:15 2003
+++ edited/drivers/video/console/sticon.c	Fri Feb 27 17:24:42 2004
@@ -250,26 +250,18 @@
     return 0;
 }
 
-static int sticon_blank(struct vc_data *c, int blank)
+static int sticon_blank(struct vc_data *c, int blank, int mode_switch)
 {
-    switch (blank) {
-    case 0:		/* unblank */
-	vga_is_gfx = 0;
-	/* Tell console.c that it has to restore the screen itself */
-	return 1;
-    case 1:		/* normal blanking */
-    default:		/* VESA blanking */
-	if (vga_is_gfx)
-		return 0;
-	sticon_set_origin(c);
-	sti_clear(sticon_sti, 0,0, c->vc_rows, c->vc_cols, BLANK);
-	return 1;
-    case -1:		/* Entering graphic mode */
-	sti_clear(sticon_sti, 0,0, c->vc_rows, c->vc_cols, BLANK);
-	vga_is_gfx = 1;
+    if (blank == 0) {
+	if (mode_switch)
+	    vga_is_gfx = 0;
 	return 1;
     }
-    return 1;		/* console needs to restore screen itself */
+    sticon_set_origin(c);
+    sti_clear(sticon_sti, 0,0, c->vc_rows, c->vc_cols, BLANK);
+    if (mode_switch)
+	vga_is_gfx = 1;
+    return 1;
 }
 
 static int sticon_scrolldelta(struct vc_data *conp, int lines)
===== drivers/video/console/vgacon.c 1.15 vs edited =====
--- 1.15/drivers/video/console/vgacon.c	Wed Mar 12 04:17:29 2003
+++ edited/drivers/video/console/vgacon.c	Fri Feb 27 17:24:57 2004
@@ -76,7 +76,7 @@
 static void vgacon_deinit(struct vc_data *c);
 static void vgacon_cursor(struct vc_data *c, int mode);
 static int vgacon_switch(struct vc_data *c);
-static int vgacon_blank(struct vc_data *c, int blank);
+static int vgacon_blank(struct vc_data *c, int blank, int mode_switch);
 static int vgacon_font_op(struct vc_data *c, struct console_font_op *op);
 static int vgacon_set_palette(struct vc_data *vc, unsigned char *table);
 static int vgacon_scrolldelta(struct vc_data *c, int lines);
@@ -661,7 +661,7 @@
 	}
 }
 
-static int vgacon_blank(struct vc_data *c, int blank)
+static int vgacon_blank(struct vc_data *c, int blank, int mode_switch)
 {
 	switch (blank) {
 	case 0:		/* Unblank */
@@ -678,7 +678,8 @@
 		/* Tell console.c that it has to restore the screen itself */
 		return 1;
 	case 1:		/* Normal blanking */
-		if (vga_video_type == VIDEO_TYPE_VGAC) {
+	case -1:	/* Obsolete */
+		if (!mode_switch && vga_video_type == VIDEO_TYPE_VGAC) {
 			vga_pal_blank(&state);
 			vga_palette_blanked = 1;
 			return 0;
@@ -686,11 +687,8 @@
 		vgacon_set_origin(c);
 		scr_memsetw((void *) vga_vram_base, BLANK,
 			    c->vc_screenbuf_size);
-		return 1;
-	case -1:		/* Entering graphic mode */
-		scr_memsetw((void *) vga_vram_base, BLANK,
-			    c->vc_screenbuf_size);
-		vga_is_gfx = 1;
+		if (mode_switch)
+			vga_is_gfx = 1;
 		return 1;
 	default:		/* VESA blanking */
 		if (vga_video_type == VIDEO_TYPE_VGAC) {
===== include/linux/console.h 1.11 vs edited =====
--- 1.11/include/linux/console.h	Wed Feb  4 16:28:11 2004
+++ edited/include/linux/console.h	Fri Feb 27 17:26:10 2004
@@ -37,7 +37,7 @@
 	int	(*con_scroll)(struct vc_data *, int, int, int, int);
 	void	(*con_bmove)(struct vc_data *, int, int, int, int, int, int);
 	int	(*con_switch)(struct vc_data *);
-	int	(*con_blank)(struct vc_data *, int);
+	int	(*con_blank)(struct vc_data *, int, int);
 	int	(*con_font_op)(struct vc_data *, struct console_font_op *);
 	int	(*con_resize)(struct vc_data *, unsigned int, unsigned int);
 	int	(*con_set_palette)(struct vc_data *, unsigned char *);
===== include/linux/fb.h 1.60 vs edited =====
--- 1.60/include/linux/fb.h	Mon Feb 16 04:07:11 2004
+++ edited/include/linux/fb.h	Fri Feb 27 17:26:19 2004
@@ -152,6 +152,7 @@
 #define FB_ACTIVATE_VBL	       16	/* activate values on next vbl  */
 #define FB_CHANGE_CMAP_VBL     32	/* change colormap on vbl	*/
 #define FB_ACTIVATE_ALL	       64	/* change all VCs on this fb	*/
+#define FB_ACTIVATE_FORCE     128	/* force apply even when no change*/
 
 #define FB_ACCELF_TEXT		1	/* text mode acceleration */
 
===== include/linux/vt_kern.h 1.9 vs edited =====
--- 1.9/include/linux/vt_kern.h	Wed Mar 12 04:17:29 2003
+++ edited/include/linux/vt_kern.h	Fri Feb 27 17:25:42 2004
@@ -44,7 +44,8 @@
 void vc_disallocate(unsigned int console);
 void reset_palette(int currcons);
 void set_palette(int currcons);
-void do_blank_screen(int gfx_mode);
+void do_blank_screen(int entering_gfx);
+void do_unblank_screen(int leaving_gfx);
 void unblank_screen(void);
 void poke_blanked_console(void);
 int con_font_op(int currcons, struct console_font_op *op);
 

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