linux/drivers/video/console
Roland Kletzing 0b9cf3aa6b mdacon messing up default vc's - set default to vc13-16 again
mdacon incorrectly detects MDA hardware on systems without such graphics card.

One may load this module by chance, for example when doing some systematical
module-testing, and if there is no Monochrome Display Adapter attached ,
module init renders vc1-16 completely unusable.

I and others have run into this more than once.  see [Bug 224522 - modprobe
mdacon freezes machine -> https://bugzilla.novell.com/show_bug.cgi?id=224522 ]
for example

Apparently  proper MDA detection seems to be broken for a long time - seems to
be related to those #ifdef TEST_MDA_B statements added by Edward Betts.

this commit back in 2002 made things even worse :
http://git.kernel.org/?p=linux/kernel/git/tglx/history.git;a=commit;h=c72757b49c88914433244757fb4967fc63546685

It changed default vc allocation from 13-16 to 1-16 for no apparent reason
(!?) , and with that (and without X), mdacon grabs the vc you`re currently
sitting on and locks you out.

this is from Kconfig :
>config MDA_CONSOLE
>        depends on !M68K && !PARISC && ISA
>        tristate "MDA text console (dual-headed) (EXPERIMENTAL)"
>        ---help---
>          Say Y here if you have an old MDA or monochrome Hercules graphics
>          adapter in your system acting as a second head ( = video card). You
>          will then be able to use two monitors with your Linux system. Do not
>          say Y here if your MDA card is the primary card in your system; the
>          normal VGA driver will handle it.

As we can see mdacon is just meant as an additional driver for dual-head
setup, and since kernel 2.4.36 still defaults to vc13-16 , setting the default
back to that value again shouldn`t do any harm.

Hereby i'm reverting that change, setting default back to to vc13-16 again.

Besides the fact that mdacon may be rarely or never be used these days and
could perhaps put to trash anyway (pre-dinosaur hardware!), indeed this is not
a real solution, but at least it removes the unfortunate side-effect of
messing up the vc you`re working on.

Signed-off-by: Roland Kletzing <devzero@web.de>
Cc: James Simmons <jsimmons@infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Tim Schmielau <tim@physik3.uni-rostock.de>
Cc: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:36 -07:00
..
bitblit.c fbcon: fix color generation for monochrome framebuffer 2008-02-06 10:41:18 -08:00
dummycon.c Remove magic macros for screen_info structure members 2007-10-16 22:57:17 -07:00
fbcon_ccw.c fbcon: fix color generation for monochrome framebuffer 2008-02-06 10:41:18 -08:00
fbcon_cw.c fbcon: fix color generation for monochrome framebuffer 2008-02-06 10:41:18 -08:00
fbcon_rotate.c
fbcon_rotate.h
fbcon_ud.c fbcon: fix color generation for monochrome framebuffer 2008-02-06 10:41:18 -08:00
fbcon.c device create: framebuffer: convert device_create to device_create_drvdata 2008-07-21 21:54:42 -07:00
fbcon.h fbcon: replace mono_col macro with static inline 2008-04-28 08:58:35 -07:00
font_6x11.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_7x14.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_8x8.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_8x16.c export font_vga_8x16 2007-10-16 09:43:19 -07:00
font_10x18.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_acorn_8x8.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_mini_4x6.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_pearl_8x8.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_sun8x16.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
font_sun12x22.c fbcon: Convert struct font_desc to use ISO C initializers 2007-10-16 09:43:17 -07:00
fonts.c cleanup after APUS removal 2008-02-06 10:41:01 -08:00
Kconfig mn10300: add the MN10300/AM33 architecture to the kernel 2008-02-08 09:22:30 -08:00
Makefile [VIDEO]: Fix section mismatch warning in promcon. 2007-06-04 23:52:45 -07:00
mdacon.c mdacon messing up default vc's - set default to vc13-16 again 2008-07-24 10:47:36 -07:00
newport_con.c netport_con.c: fix build errors and warnings 2007-10-18 14:37:17 -07:00
prom.uni
promcon.c vt: add color support to the "underline" and "italic" attributes 2007-05-08 11:15:27 -07:00
softcursor.c fbdev: change asm/uaccess.h to linux/uaccess.h 2007-10-16 09:43:17 -07:00
sticon.c vt: fix background color on line feed 2008-04-29 08:06:06 -07:00
sticore.c [PARISC] Clean up sti_flush 2007-08-27 00:29:23 -04:00
tileblit.c fbcon: fix color generation for monochrome framebuffer 2008-02-06 10:41:18 -08:00
vgacon.c vt: fix background color on line feed 2008-04-29 08:06:06 -07:00