Merge branch 'resizex' (patches from Maciej)

Merge VT_RESIZEX fixes from Maciej Rozycki:
 "I got to the bottom of the issue with VT_RESIZEX recently discussed
  and came up with this small patch series, fixing an additional issue
  that I originally thought might be broken VGA hardware emulation with
  my laptop, which however turned out to be intertwined with the
  original problem and also a regression introduced somewhat later.

  The fix for that because the first patch, and then to make backporting
  feasible I had to put a revert of the offending change from last
  September next, followed by a proper fix for the framebuffer issue
  that change had tried to address.

  See individual change descriptions for details.

  These have been verified with true VGA hardware (a Trident TVGA8900
  ISA video adapter) using various combinations of `svgatextmode' and
  `setfont' command invocations to change both the VT size and the font
  size, and also switching between the text console and X11, both by
  starting/stopping the X server and by switching between VTs.

  All this to ensure bringing the behaviour of VGA text console back to
  correct operation as it used to be with Linux 2.6.18"

* emailed patches from Maciej W. Rozycki <macro@orcam.me.uk>:
  vt: Fix character height handling with VT_RESIZEX
  vt_ioctl: Revert VT_RESIZEX parameter handling removal
  vgacon: Record video mode changes with VT_RESIZEX

3 files changed, 80 insertions, 34 deletions

diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index 89aeaf3c1bca..0e0cd9e9e589 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -671,21 +671,58 @@ static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
 	if (copy_from_user(&v, cs, sizeof(struct vt_consize)))
 		return -EFAULT;
 
-	if (v.v_vlin)
-		pr_info_once("\"struct vt_consize\"->v_vlin is ignored. Please report if you need this.\n");
-	if (v.v_clin)
-		pr_info_once("\"struct vt_consize\"->v_clin is ignored. Please report if you need this.\n");
+	/* FIXME: Should check the copies properly */
+	if (!v.v_vlin)
+		v.v_vlin = vc->vc_scan_lines;
+
+	if (v.v_clin) {
+		int rows = v.v_vlin / v.v_clin;
+		if (v.v_rows != rows) {
+			if (v.v_rows) /* Parameters don't add up */
+				return -EINVAL;
+			v.v_rows = rows;
+		}
+	}
+
+	if (v.v_vcol && v.v_ccol) {
+		int cols = v.v_vcol / v.v_ccol;
+		if (v.v_cols != cols) {
+			if (v.v_cols)
+				return -EINVAL;
+			v.v_cols = cols;
+		}
+	}
+
+	if (v.v_clin > 32)
+		return -EINVAL;
 
-	console_lock();
 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
-		vc = vc_cons[i].d;
+		struct vc_data *vcp;
 
-		if (vc) {
-			vc->vc_resize_user = 1;
-			vc_resize(vc, v.v_cols, v.v_rows);
+		if (!vc_cons[i].d)
+			continue;
+		console_lock();
+		vcp = vc_cons[i].d;
+		if (vcp) {
+			int ret;
+			int save_scan_lines = vcp->vc_scan_lines;
+			int save_cell_height = vcp->vc_cell_height;
+
+			if (v.v_vlin)
+				vcp->vc_scan_lines = v.v_vlin;
+			if (v.v_clin)
+				vcp->vc_cell_height = v.v_clin;
+			vcp->vc_resize_user = 1;
+			ret = vc_resize(vcp, v.v_cols, v.v_rows);
+			if (ret) {
+				vcp->vc_scan_lines = save_scan_lines;
+				vcp->vc_cell_height = save_cell_height;
+				console_unlock();
+				return ret;
+			}
 		}
+		console_unlock();
 	}
-	console_unlock();
 
 	return 0;
 }
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 39258f9d36a0..ef9c57ce0906 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -380,7 +380,7 @@ static void vgacon_init(struct vc_data *c, int init)
 		vc_resize(c, vga_video_num_columns, vga_video_num_lines);
 
 	c->vc_scan_lines = vga_scan_lines;
-	c->vc_font.height = vga_video_font_height;
+	c->vc_font.height = c->vc_cell_height = vga_video_font_height;
 	c->vc_complement_mask = 0x7700;
 	if (vga_512_chars)
 		c->vc_hi_font_mask = 0x0800;
@@ -515,32 +515,32 @@ static void vgacon_cursor(struct vc_data *c, int mode)
 		switch (CUR_SIZE(c->vc_cursor_type)) {
 		case CUR_UNDERLINE:
 			vgacon_set_cursor_size(c->state.x,
-					       c->vc_font.height -
-					       (c->vc_font.height <
+					       c->vc_cell_height -
+					       (c->vc_cell_height <
 						10 ? 2 : 3),
-					       c->vc_font.height -
-					       (c->vc_font.height <
+					       c->vc_cell_height -
+					       (c->vc_cell_height <
 						10 ? 1 : 2));
 			break;
 		case CUR_TWO_THIRDS:
 			vgacon_set_cursor_size(c->state.x,
-					       c->vc_font.height / 3,
-					       c->vc_font.height -
-					       (c->vc_font.height <
+					       c->vc_cell_height / 3,
+					       c->vc_cell_height -
+					       (c->vc_cell_height <
 						10 ? 1 : 2));
 			break;
 		case CUR_LOWER_THIRD:
 			vgacon_set_cursor_size(c->state.x,
-					       (c->vc_font.height * 2) / 3,
-					       c->vc_font.height -
-					       (c->vc_font.height <
+					       (c->vc_cell_height * 2) / 3,
+					       c->vc_cell_height -
+					       (c->vc_cell_height <
 						10 ? 1 : 2));
 			break;
 		case CUR_LOWER_HALF:
 			vgacon_set_cursor_size(c->state.x,
-					       c->vc_font.height / 2,
-					       c->vc_font.height -
-					       (c->vc_font.height <
+					       c->vc_cell_height / 2,
+					       c->vc_cell_height -
+					       (c->vc_cell_height <
 						10 ? 1 : 2));
 			break;
 		case CUR_NONE:
@@ -551,7 +551,7 @@ static void vgacon_cursor(struct vc_data *c, int mode)
 			break;
 		default:
 			vgacon_set_cursor_size(c->state.x, 1,
-					       c->vc_font.height);
+					       c->vc_cell_height);
 			break;
 		}
 		break;
@@ -562,13 +562,13 @@ static int vgacon_doresize(struct vc_data *c,
 		unsigned int width, unsigned int height)
 {
 	unsigned long flags;
-	unsigned int scanlines = height * c->vc_font.height;
+	unsigned int scanlines = height * c->vc_cell_height;
 	u8 scanlines_lo = 0, r7 = 0, vsync_end = 0, mode, max_scan;
 
 	raw_spin_lock_irqsave(&vga_lock, flags);
 
 	vgacon_xres = width * VGA_FONTWIDTH;
-	vgacon_yres = height * c->vc_font.height;
+	vgacon_yres = height * c->vc_cell_height;
 	if (vga_video_type >= VIDEO_TYPE_VGAC) {
 		outb_p(VGA_CRTC_MAX_SCAN, vga_video_port_reg);
 		max_scan = inb_p(vga_video_port_val);
@@ -623,9 +623,9 @@ static int vgacon_doresize(struct vc_data *c,
 static int vgacon_switch(struct vc_data *c)
 {
 	int x = c->vc_cols * VGA_FONTWIDTH;
-	int y = c->vc_rows * c->vc_font.height;
+	int y = c->vc_rows * c->vc_cell_height;
 	int rows = screen_info.orig_video_lines * vga_default_font_height/
-		c->vc_font.height;
+		c->vc_cell_height;
 	/*
 	 * We need to save screen size here as it's the only way
 	 * we can spot the screen has been resized and we need to
@@ -1038,7 +1038,7 @@ static int vgacon_adjust_height(struct vc_data *vc, unsigned fontheight)
 				cursor_size_lastto = 0;
 				c->vc_sw->con_cursor(c, CM_DRAW);
 			}
-			c->vc_font.height = fontheight;
+			c->vc_font.height = c->vc_cell_height = fontheight;
 			vc_resize(c, 0, rows);	/* Adjust console size */
 		}
 	}
@@ -1086,12 +1086,20 @@ static int vgacon_resize(struct vc_data *c, unsigned int width,
 	if ((width << 1) * height > vga_vram_size)
 		return -EINVAL;
 
+	if (user) {
+		/*
+		 * Ho ho!  Someone (svgatextmode, eh?) may have reprogrammed
+		 * the video mode!  Set the new defaults then and go away.
+		 */
+		screen_info.orig_video_cols = width;
+		screen_info.orig_video_lines = height;
+		vga_default_font_height = c->vc_cell_height;
+		return 0;
+	}
 	if (width % 2 || width > screen_info.orig_video_cols ||
 	    height > (screen_info.orig_video_lines * vga_default_font_height)/
-	    c->vc_font.height)
-		/* let svgatextmode tinker with video timings and
-		   return success */
-		return (user) ? 0 : -EINVAL;
+	    c->vc_cell_height)
+		return -EINVAL;
 
 	if (con_is_visible(c) && !vga_is_gfx) /* who knows */
 		vgacon_doresize(c, width, height);
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index 153734816b49..d5b9c8d40c18 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -101,6 +101,7 @@ struct vc_data {
 	unsigned int	vc_rows;
 	unsigned int	vc_size_row;		/* Bytes per row */
 	unsigned int	vc_scan_lines;		/* # of scan lines */
+	unsigned int	vc_cell_height;		/* CRTC character cell height */
 	unsigned long	vc_origin;		/* [!] Start of real screen */
 	unsigned long	vc_scr_end;		/* [!] End of real screen */
 	unsigned long	vc_visible_origin;	/* [!] Top of visible window */