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[PATCH] vga text console and stty cols/rows

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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: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Samuel Thibault 2005-09-09 13:01:58 -07:00 committed by Linus Torvalds
parent ff55fe2075
commit 28254d439b
1 changed files with 69 additions and 2 deletions
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71
drivers/video/console/vgacon.c
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@ -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,