[PATCH] VGA console font problems on 2.6 kernel

From: Egbert Eich <eich@suse.de>

I would like to utilize kernel ioctls to save/restore console fonts
in VGA text mode when running X. So far the Xserver takes care of this
however there more and more problems with this:
        1. On some platforms (IA64) we need to POST the BIOS before
	   we even have a chance to access the hardware ourselves.
	   This POSTing will usually undo any changes to the graphics
	   hardware that the kernel may have done.
	2. More and more drivers fully rely on BIOS support however
	   the BIOS functions which could be used to save/restore
	   register settings may be broken so the only way of mode
	   save/restore is getting/setting the BIOS mode ID.

I've hacked up some code for X however I ran into two problems:

1. con_font_get() in linux/drivers/char/vt.c seems to be broken as
   the font parameters (height, width, charcount) are never reported
   back. Therefore this function seems to be pretty useless.
   The fix is simple (please see below).

2. fb consoles seem to allow to install fonts per vt so that the user
   can have a different font on every console. The text console driver
   doesn't support this: the font is downloaded to the video card
   and will be used for all systems. Still the vga_con driver stores
   the font parameters per console with the effect that setting a
   font with different parameters on one console will result in the
   wron values when this font information is read back from another
   console.
   Appearantly this broken feature has been introduced in 2.6 as
   in the 2.4 kernel the vga_con font information is stored in one
   single global variable.

The IA64 platform at least still heavily relies on the VGA text console.
To be able to fix some VT switching issues with X on this platform I
need these two issues resolved.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 31da37da5f400c7a44c200fd932cf85b9d733118..cffa77b926290893e05cb2c00f71a88c132c4755 100644 (file)
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -3077,6 +3077,10 @@ int con_font_get(int currcons, struct console_font_op *op)
        if (rc)
                goto out;
 
+       op->height = font.height;
+       op->width = font.width;
+       op->charcount = font.charcount;
+
        if (op->data && copy_to_user(op->data, font.data, c))
                rc = -EFAULT;
 

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 0e91d6b577e44c06abbbfdea8100cfb414206ac4..61181b2d7a19554037d6404eb34e5331c6ec67a2 100644 (file)
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -901,8 +901,10 @@ static int vgacon_adjust_height(struct vc_data *vc, unsigned fontheight)
        for (i = 0; i < MAX_NR_CONSOLES; i++) {
                struct vc_data *c = vc_cons[i].d;
 
-               if (c && c->vc_sw == &vga_con)
+               if (c && c->vc_sw == &vga_con) {
+                       c->vc_font.height = fontheight;
                        vc_resize(c->vc_num, 0, rows);  /* Adjust console size */
+               }
        }
        return 0;
 }