Make pcvt and syscons live in the same kernel. If both are enabled, then

the first one in the config has priority.  They can be switched using
userconfig().

i386/i386/conf.c:
Initialize the shared syscons/pcvt cdevsw entry to `nx'.

Add cdevsw registration functions.

Use devsw functions of the correct type if they exist.

i386/i386/cons.c:
Add renamed syscons entry points to constab.

i386/i386/cons.h:
Declare the renamed syscons entry points.

i386/i386/machdep.c:
Repeat console initialization after userconfig() in case the current
console has become wrong.  This depends on cn functions not wiring down
anything important.

sys/conf.h:
Declare new functions.

i386/isa/isa.[ch]:
Add a function to decide which display driver has priority.  Should be
done better.

i386/isa/syscons.c:
Rename pccn* -> sccn*.

Initialize CRTC start address in case the previous driver has moved it.

i386/isa/syscons.c, i386/isa/pcvt/*
Initialize the bogusly shared variable Crtat dynamically in case the
stored value was changed by the previous driver.

Initialize cdevsw table from a template.

Don't grab the console if another display driver has priority.

i386/isa/syscons.h, i386/isa/pcvt/pcvt_hdr.h:
Don't externally declare now-static cdevsw functions.

i386/isa/pcvt/pcvt_hdr.h:
Set the sensitive hardware flag so that pcvt doesn't always have lower
priority than syscons.  This also fixes the "stupid" detection of the
display after filling the display with text.

i386/isa/pcvt/pcvt_out.c:
Don't be confused the off-screen cursor offset 0xffff set by syscons.

kern/subr_xxx.c:
Add enough nxio/nodev/null devsw functions of the correct type for syscons
and pcvt.

1 files changed, 16 insertions, 2 deletions

diff --git a/sys/i386/isa/pcvt/pcvt_out.c b/sys/i386/isa/pcvt/pcvt_out.c
index 945ee24..fc76517 100644
--- a/sys/i386/isa/pcvt/pcvt_out.c
+++ b/sys/i386/isa/pcvt/pcvt_out.c
@@ -892,13 +892,17 @@ sput (u_char *s, U_char kernel, int len, int page)
 static void
 vt_coldinit(void)
 {
-	u_short volatile *cp = Crtat + (CGA_BUF-MONO_BUF)/CHR;
+	u_short volatile *cp;
 	u_short was;
 	int nscr, charset;
 	int equipment;
-	u_short *SaveCrtat = Crtat;
+	u_short *SaveCrtat;
 	struct video_state *svsp;
 
+	Crtat = (u_short *)MONO_BUF;	/* XXX assume static relocation works */
+	SaveCrtat = Crtat;
+	cp = Crtat + (CGA_BUF-MONO_BUF)/CHR;
+
 	do_initialization = 0;		/* reset init necessary flag */
 
 	/* get the equipment byte from the RTC chip */
@@ -1121,6 +1125,16 @@ vt_coldinit(void)
 			outb(addr_6845, CRTC_CURSORL);
 			cursorat |= inb(addr_6845+1);
 
+			/*
+			 * Reject cursors that are more than one row off a
+			 * 25-row screen.  syscons sets the cursor offset
+			 * to 0xffff. The scroll up fixup fails for this
+			 * because the assignment to svsp->row overflows
+			 * and perhaps for other reasons.
+			 */
+			if (cursorat > 25 * svsp->maxcol)
+				cursorat = 25 * svsp->maxcol;
+
 			svsp->cur_offset = cursorat;
 			svsp->row = cursorat / svsp->maxcol;
 			svsp->col = cursorat % svsp->maxcol;