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authorJoe Millenbach <jmillenbach@gmail.com>2013-01-17 22:44:22 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-18 16:15:27 -0800
commit4f73bc4dd3e8563ef4109f293a092820dff66d92 (patch)
tree8ebd5d01abaceb70da1932db1a5e7219630b0fd3 /drivers/tty/Kconfig
parenta1bf9584429d61b7096f93ae09325e1ba538e9e8 (diff)
downloadop-kernel-dev-4f73bc4dd3e8563ef4109f293a092820dff66d92.zip
op-kernel-dev-4f73bc4dd3e8563ef4109f293a092820dff66d92.tar.gz
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>
Diffstat (limited to 'drivers/tty/Kconfig')
-rw-r--r--drivers/tty/Kconfig13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index 0ecf22b..a79fd8e 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -1,3 +1,14 @@
+config TTY
+ bool "Enable TTY" if EXPERT
+ default y
+ ---help---
+ Allows you to remove TTY support which can save space, and
+ blocks features that require TTY from inclusion in the kernel.
+ TTY is required for any text terminals or serial port
+ communication. Most users should leave this enabled.
+
+if TTY
+
config VT
bool "Virtual terminal" if EXPERT
depends on !S390 && !UML
@@ -388,3 +399,5 @@ config PPC_EARLY_DEBUG_EHV_BC_HANDLE
If the number you specify is not a valid byte channel handle, then
there simply will be no early console output. This is true also
if you don't boot under a hypervisor at all.
+
+endif # TTY
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