Commit 210a1ce8 authored by Finn Thain's avatar Finn Thain Committed by Geert Uytterhoeven
Browse files

m68k: Fix lost column on framebuffer debug console 



Move the cursor position rightward after rendering the character,
not before. This avoids complications that arise when the recursive
console_putc call has to wrap the line and/or scroll the display.
This also fixes the linewrap bug that crops off the rightmost column.

When the cursor is at the bottom of the display, a linefeed will not
move the cursor position further downward. Instead, the display scrolls
upward. Avoid the repeated add/subtract sequence by way of a single
subtraction at the initialization of console_struct_num_rows.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarFinn Thain <fthain@linux-m68k.org>
Tested-by: default avatarStan Johnson <userm57@yahoo.com>
Reviewed-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/9d4e8c68a456d5f2bc254ac6f87a472d066ebd5e.1743115195.git.fthain@linux-m68k.org


Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 8135422a

arch/m68k/kernel/head.S

+21 −10
Original line number Diff line number Diff line
@@ -3400,6 +3400,7 @@ L(console_clear_loop): 


	movel	%d4,%d1				/* screen height in pixels */

	divul	%a0@(FONT_DESC_HEIGHT),%d1	/* d1 = max num rows */

	subql	#1,%d1				/* row range is 0 to num - 1 */



	movel	%d0,%a2@(Lconsole_struct_num_columns)

	movel	%d1,%a2@(Lconsole_struct_num_rows)
@@ -3546,15 +3547,14 @@ func_start console_putc,%a0/%a1/%d0-%d7 
	cmpib	#10,%d7

	jne	L(console_not_lf)

	movel	%a0@(Lconsole_struct_cur_row),%d0

	addil	#1,%d0

	movel	%d0,%a0@(Lconsole_struct_cur_row)

	movel	%a0@(Lconsole_struct_num_rows),%d1

	cmpl	%d1,%d0

	jcs	1f

	subil	#1,%d0

	movel	%d0,%a0@(Lconsole_struct_cur_row)

	console_scroll

	jra	L(console_exit)

1:

	addql	#1,%d0

	movel	%d0,%a0@(Lconsole_struct_cur_row)

	jra	L(console_exit)



L(console_not_lf):
@@ -3581,12 +3581,6 @@ L(console_not_cr): 
 */

L(console_not_home):

	movel	%a0@(Lconsole_struct_cur_column),%d0

	addql	#1,%a0@(Lconsole_struct_cur_column)

	movel	%a0@(Lconsole_struct_num_columns),%d1

	cmpl	%d1,%d0

	jcs	1f

	console_putc	#'\n'	/* recursion is OK! */

1:

	movel	%a0@(Lconsole_struct_cur_row),%d1



	/*
@@ -3633,6 +3627,23 @@ L(console_do_font_scanline): 
	addq	#1,%d1

	dbra	%d7,L(console_read_char_scanline)



	/*

	 *	Register usage in the code below:

	 *	a0 = pointer to console globals

	 *	d0 = cursor column

	 *	d1 = cursor column limit

	 */



	lea	%pc@(L(console_globals)),%a0



	movel	%a0@(Lconsole_struct_cur_column),%d0

	addql	#1,%d0

	movel	%d0,%a0@(Lconsole_struct_cur_column)	/* Update cursor pos */

	movel	%a0@(Lconsole_struct_num_columns),%d1

	cmpl	%d1,%d0

	jcs	L(console_exit)

	console_putc	#'\n'		/* Line wrap using tail recursion */



L(console_exit):

func_return	console_putc