stuartl/linux-stable
1
0
Fork 0
mirror of https://kernel.googlesource.com/pub/scm/linux/kernel/git/stable/linux-stable.git synced 2025-09-14 11:19:08 +10:00
Code Issues Releases Wiki Activity

m68k: Fix lost column on framebuffer debug console

Browse Source 
commit 210a1ce8ed upstream.

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: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Tested-by: Stan Johnson <userm57@yahoo.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/9d4e8c68a456d5f2bc254ac6f87a472d066ebd5e.1743115195.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Finn Thain 2025-03-28 09:39:55 +11:00 committed by Greg Kroah-Hartman
parent 177d3651db
commit 5e5ccfdbe4
1 changed files with 21 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
arch/m68k/kernel/head.S
View File

@ -3379,6 +3379,7 @@ L(console_clear_loop):
movel %d4,%d1 /* screen height in pixels */ movel %d4,%d1 /* screen height in pixels */
divul %a0@(FONT_DESC_HEIGHT),%d1 /* d1 = max num rows */ 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 %d0,%a2@(Lconsole_struct_num_columns)
movel %d1,%a2@(Lconsole_struct_num_rows) movel %d1,%a2@(Lconsole_struct_num_rows)
@ -3525,15 +3526,14 @@ func_start console_putc,%a0/%a1/%d0-%d7
cmpib #10,%d7 cmpib #10,%d7
jne L(console_not_lf) jne L(console_not_lf)
movel %a0@(Lconsole_struct_cur_row),%d0 movel %a0@(Lconsole_struct_cur_row),%d0
addil #1,%d0
movel %d0,%a0@(Lconsole_struct_cur_row)
movel %a0@(Lconsole_struct_num_rows),%d1 movel %a0@(Lconsole_struct_num_rows),%d1
cmpl %d1,%d0 cmpl %d1,%d0
jcs 1f jcs 1f
subil #1,%d0
movel %d0,%a0@(Lconsole_struct_cur_row)
console_scroll console_scroll
jra L(console_exit)
1: 1:
addql #1,%d0
movel %d0,%a0@(Lconsole_struct_cur_row)
jra L(console_exit) jra L(console_exit)
L(console_not_lf): L(console_not_lf):
@ -3560,12 +3560,6 @@ L(console_not_cr):
*/ */
L(console_not_home): L(console_not_home):
movel %a0@(Lconsole_struct_cur_column),%d0 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 movel %a0@(Lconsole_struct_cur_row),%d1
/* /*
@ -3612,6 +3606,23 @@ L(console_do_font_scanline):
addq #1,%d1 addq #1,%d1
dbra %d7,L(console_read_char_scanline) 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): L(console_exit):
func_return console_putc func_return console_putc