[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: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index d27fa91..0705cd7 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -497,6 +497,57 @@
}
}
+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 @@
/* 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 @@
#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 @@
.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,
