Please disregard the patch below. Further testing shows that it does not completely solve the problem. In particular, when line-wrap also produces vertical scrolling. I think the recursive console_putc call may have to go.
On Fri, 7 Mar 2025, Finn Thain wrote:
When long lines are sent to the debug console on the framebuffer, the right-most column is lost. Fix this by subtracting 1 from the column count before comparing it with console_struct_cur_column, as the latter counts from zero.
Linewrap is handled with a recursive call to console_putc, but this alters the console_struct_cur_row global. Store the old value before calling console_putc, so the right-most character gets rendered on the correct line.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Finn Thain fthain@linux-m68k.org
arch/m68k/kernel/head.S | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S index 852255cf60de..9c60047764d0 100644 --- a/arch/m68k/kernel/head.S +++ b/arch/m68k/kernel/head.S @@ -3583,11 +3583,16 @@ 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
- subil #1,%d1 cmpl %d1,%d0 jcs 1f
- console_putc #'\n' /* recursion is OK! */
- /* recursion will alter console_struct so load d1 register first */
- movel %a0@(Lconsole_struct_cur_row),%d1
- console_putc #'\n'
- jmp 2f
1: movel %a0@(Lconsole_struct_cur_row),%d1 +2: /* * At this point we make a shift in register usage