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Commit 28254d43 authored by Samuel Thibault's avatar Samuel Thibault Committed by Linus Torvalds
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[PATCH] vga text console and stty cols/rows 

Some people use 66-cells braille devices for reading the console, and hence
would like to reduce the width of the screen by using:

stty cols 66

However, the vga text console doesn't behave correctly: the 14 first
characters of the second line are put on the right of the first line and so
forth.

Here is a patch to correct that.  It corrects the disp_end and offset
registers of the vga board on console resize and console switch.

On usual screens, you then correctly get a right and/or bottom blank
margin.  On some laptop panels, the output is resized so that text actually
gets magnified, which can be great for some people (see
http://dept-info.labri.fr/~thibault/ls.jpg

 ).

Signed-off-by: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ff55fe20

drivers/video/console/vgacon.c

+69 −2
Original line number Diff line number Diff line
@@ -497,6 +497,57 @@ static void vgacon_cursor(struct vc_data *c, int mode) 
	}

}



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;

	u8 scanlines_lo, r7, vsync_end, mode;



	spin_lock_irqsave(&vga_lock, flags);



	outb_p(VGA_CRTC_MODE, vga_video_port_reg);

	mode = inb_p(vga_video_port_val);



	if (mode & 0x04)

		scanlines >>= 1;



	scanlines -= 1;

	scanlines_lo = scanlines & 0xff;



	outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);

	r7 = inb_p(vga_video_port_val) & ~0x42;



	if (scanlines & 0x100)

		r7 |= 0x02;

	if (scanlines & 0x200)

		r7 |= 0x40;



	/* deprotect registers */

	outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);

	vsync_end = inb_p(vga_video_port_val);

	outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);

	outb_p(vsync_end & ~0x80, vga_video_port_val);



	outb_p(VGA_CRTC_H_DISP, vga_video_port_reg);

	outb_p(width - 1, vga_video_port_val);

	outb_p(VGA_CRTC_OFFSET, vga_video_port_reg);

	outb_p(width >> 1, vga_video_port_val);



	outb_p(VGA_CRTC_V_DISP_END, vga_video_port_reg);

	outb_p(scanlines_lo, vga_video_port_val);

	outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);

	outb_p(r7,vga_video_port_val);



	/* reprotect registers */

	outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);

	outb_p(vsync_end, vga_video_port_val);



	spin_unlock_irqrestore(&vga_lock, flags);



	return 0;

}



static int vgacon_switch(struct vc_data *c)

{

	/*
@@ -510,9 +561,13 @@ static int vgacon_switch(struct vc_data *c) 
	/* We can only copy out the size of the video buffer here,

	 * otherwise we get into VGA BIOS */



	if (!vga_is_gfx)

	if (!vga_is_gfx) {

		scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf,

			    c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size);

			    c->vc_screenbuf_size > vga_vram_size ?

				vga_vram_size : c->vc_screenbuf_size);

		vgacon_doresize(c, c->vc_cols, c->vc_rows);

	}



	return 0;		/* Redrawing not needed */

}
@@ -962,6 +1017,17 @@ static int vgacon_font_get(struct vc_data *c, struct console_font *font) 


#endif



static int vgacon_resize(struct vc_data *c, unsigned int width,

				unsigned int height)

{

	if (width % 2 || width > ORIG_VIDEO_COLS || height > ORIG_VIDEO_LINES)

		return -EINVAL;



	if (CON_IS_VISIBLE(c) && !vga_is_gfx) /* who knows */

		vgacon_doresize(c, width, height);

	return 0;

}



static int vgacon_scrolldelta(struct vc_data *c, int lines)

{

	if (!lines)		/* Turn scrollback off */
@@ -1103,6 +1169,7 @@ const struct consw vga_con = { 
	.con_blank = vgacon_blank,

	.con_font_set = vgacon_font_set,

	.con_font_get = vgacon_font_get,

	.con_resize = vgacon_resize,

	.con_set_palette = vgacon_set_palette,

	.con_scrolldelta = vgacon_scrolldelta,

	.con_set_origin = vgacon_set_origin,