tty: Added a CONFIG_TTY option to allow removal of TTY
The option allows you to remove TTY and compile without errors. This
saves space on systems that won't support TTY interfaces anyway.
bloat-o-meter output is below.
The bulk of this patch consists of Kconfig changes adding "depends on
TTY" to various serial devices and similar drivers that require the TTY
layer. Ideally, these dependencies would occur on a common intermediate
symbol such as SERIO, but most drivers "select SERIO" rather than
"depends on SERIO", and "select" does not respect dependencies.
bloat-o-meter output comparing our previous minimal to new minimal by
removing TTY. The list is filtered to not show removed entries with awk
'$3 != "-"' as the list was very long.
add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350)
function old new delta
chr_dev_init 166 170 +4
allow_signal 80 82 +2
static.__warned 143 142 -1
disallow_signal 63 62 -1
__set_special_pids 95 94 -1
unregister_console 126 121 -5
start_kernel 546 541 -5
register_console 593 588 -5
copy_from_user 45 40 -5
sys_setsid 128 120 -8
sys_vhangup 32 19 -13
do_exit 1543 1526 -17
bitmap_zero 60 40 -20
arch_local_irq_save 137 117 -20
release_task 674 652 -22
static.spin_unlock_irqrestore 308 260 -48
Signed-off-by: Joe Millenbach <jmillenbach@gmail.com>
Reviewed-by: Jamey Sharp <jamey@minilop.net>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
index 43cb93f..30894fa 100644
--- a/lib/Kconfig.kgdb
+++ b/lib/Kconfig.kgdb
@@ -22,6 +22,7 @@
tristate "KGDB: use kgdb over the serial console"
select CONSOLE_POLL
select MAGIC_SYSRQ
+ depends on TTY
default y
help
Share a serial console with kgdb. Sysrq-g must be used