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authorRoland Kletzing <devzero@web.de>2008-07-23 21:31:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:36 -0700
commit0b9cf3aa6b1e934807b40b4d478d7e11f7c43f55 (patch)
treea666e7fbc7c65d39e71eb5f56bc4c3fd6fe0e953
parent663b0e15877293451bdfea619db45eafae9dec54 (diff)
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>
-rw-r--r--drivers/video/console/mdacon.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
index 38a296bbdfc..9901064199b 100644
--- a/drivers/video/console/mdacon.c
+++ b/drivers/video/console/mdacon.c
@@ -71,13 +71,15 @@ static char *mda_type_name;
/* console information */
-static int mda_first_vc = 1;
+static int mda_first_vc = 13;
static int mda_last_vc = 16;
static struct vc_data *mda_display_fg = NULL;
module_param(mda_first_vc, int, 0);
+MODULE_PARM_DESC(mda_first_vc, "First virtual console. Default: 13");
module_param(mda_last_vc, int, 0);
+MODULE_PARM_DESC(mda_last_vc, "Last virtual console. Default: 16");
/* MDA register values
*/