diff options
| author | Finn Thain <fthain@linux-m68k.org> | 2025-03-28 09:39:55 +1100 |
|---|---|---|
| committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2025-07-06 12:50:50 +0200 |
| commit | 210a1ce8ed4391b64a888b3fb4b5611a13f5ccc7 (patch) | |
| tree | 7b30f99a4717ba79aed4a3957dc57018cbe36786 | |
| parent | 8135422ae047fe0d5b7e8017f3fd43cf4dfa80c4 (diff) | |
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: 1da177e4c3f4 ("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>
| -rw-r--r-- | arch/m68k/kernel/head.S | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S index 852255cf60de..9bd8adaa756d 100644 --- a/arch/m68k/kernel/head.S +++ b/arch/m68k/kernel/head.S @@ -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 |