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Greg Kroah-Hartman38c91d12019-04-02 16:07:07 +02001# SPDX-License-Identifier: GPL-2.0
Joe Millenbach4f73bc42013-01-17 22:44:22 -08002config TTY
3 bool "Enable TTY" if EXPERT
4 default y
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +09005 help
Joe Millenbach4f73bc42013-01-17 22:44:22 -08006 Allows you to remove TTY support which can save space, and
7 blocks features that require TTY from inclusion in the kernel.
8 TTY is required for any text terminals or serial port
9 communication. Most users should leave this enabled.
10
11if TTY
12
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080013config VT
14 bool "Virtual terminal" if EXPERT
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080015 select INPUT
Johannes Berg0bbadaf2021-03-05 13:19:51 +010016 default y if !UML
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +090017 help
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080018 If you say Y here, you will get support for terminal devices with
19 display and keyboard devices. These are called "virtual" because you
20 can run several virtual terminals (also called virtual consoles) on
21 one physical terminal. This is rather useful, for example one
22 virtual terminal can collect system messages and warnings, another
23 one can be used for a text-mode user session, and a third could run
24 an X session, all in parallel. Switching between virtual terminals
25 is done with certain key combinations, usually Alt-<function key>.
26
27 The setterm command ("man setterm") can be used to change the
28 properties (such as colors or beeping) of a virtual terminal. The
29 man page console_codes(4) ("man console_codes") contains the special
30 character sequences that can be used to change those properties
31 directly. The fonts used on virtual terminals can be changed with
32 the setfont ("man setfont") command and the key bindings are defined
33 with the loadkeys ("man loadkeys") command.
34
35 You need at least one virtual terminal device in order to make use
36 of your keyboard and monitor. Therefore, only people configuring an
37 embedded system would want to say N here in order to save some
38 memory; the only way to log into such a system is then via a serial
39 or network connection.
40
41 If unsure, say Y, or else you won't be able to do much with your new
42 shiny Linux system :-)
43
44config CONSOLE_TRANSLATIONS
45 depends on VT
46 default y
47 bool "Enable character translations in console" if EXPERT
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +090048 help
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080049 This enables support for font mapping and Unicode translation
50 on virtual consoles.
51
52config VT_CONSOLE
53 bool "Support for console on virtual terminal" if EXPERT
54 depends on VT
55 default y
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +090056 help
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080057 The system console is the device which receives all kernel messages
58 and warnings and which allows logins in single user mode. If you
59 answer Y here, a virtual terminal (the device used to interact with
60 a physical terminal) can be used as system console. This is the most
61 common mode of operations, so you should say Y here unless you want
62 the kernel messages be output only to a serial port (in which case
63 you should say Y to "Console on serial port", below).
64
65 If you do say Y here, by default the currently visible virtual
66 terminal (/dev/tty0) will be used as system console. You can change
67 that with a kernel command line option such as "console=tty3" which
68 would use the third virtual terminal as system console. (Try "man
69 bootparam" or see the documentation of your boot loader (lilo or
70 loadlin) about how to pass options to the kernel at boot time.)
71
72 If unsure, say Y.
73
H Hartley Sweeten37cce262011-09-21 22:47:55 +020074config VT_CONSOLE_SLEEP
75 def_bool y
76 depends on VT_CONSOLE && PM_SLEEP
77
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080078config HW_CONSOLE
79 bool
Johannes Berg0bbadaf2021-03-05 13:19:51 +010080 depends on VT
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080081 default y
82
83config VT_HW_CONSOLE_BINDING
Krzysztof Kozlowskida88ac02019-11-21 21:28:47 +080084 bool "Support for binding and unbinding console drivers"
85 depends on HW_CONSOLE
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +090086 help
Krzysztof Kozlowskida88ac02019-11-21 21:28:47 +080087 The virtual terminal is the device that interacts with the physical
88 terminal through console drivers. On these systems, at least one
89 console driver is loaded. In other configurations, additional console
90 drivers may be enabled, such as the framebuffer console. If more than
91 1 console driver is enabled, setting this to 'y' will allow you to
92 select the console driver that will serve as the backend for the
93 virtual terminals.
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080094
Krzysztof Kozlowskida88ac02019-11-21 21:28:47 +080095 See <file:Documentation/driver-api/console.rst> for more
96 information. For framebuffer console users, please refer to
97 <file:Documentation/fb/fbcon.rst>.
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -080098
99config UNIX98_PTYS
100 bool "Unix98 PTY support" if EXPERT
101 default y
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900102 help
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -0800103 A pseudo terminal (PTY) is a software device consisting of two
104 halves: a master and a slave. The slave device behaves identical to
105 a physical terminal; the master device is used by a process to
106 read data from and write data to the slave, thereby emulating a
107 terminal. Typical programs for the master side are telnet servers
108 and xterms.
109
110 Linux has traditionally used the BSD-like names /dev/ptyxx for
111 masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
112 has a number of problems. The GNU C library glibc 2.1 and later,
113 however, supports the Unix98 naming standard: in order to acquire a
114 pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
115 terminal is then made available to the process and the pseudo
116 terminal slave can be accessed as /dev/pts/<number>. What was
117 traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
118
119 All modern Linux systems use the Unix98 ptys. Say Y unless
120 you're on an embedded system and want to conserve memory.
121
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -0800122config LEGACY_PTYS
123 bool "Legacy (BSD) PTY support"
124 default y
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900125 help
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -0800126 A pseudo terminal (PTY) is a software device consisting of two
127 halves: a master and a slave. The slave device behaves identical to
128 a physical terminal; the master device is used by a process to
129 read data from and write data to the slave, thereby emulating a
130 terminal. Typical programs for the master side are telnet servers
131 and xterms.
132
133 Linux has traditionally used the BSD-like names /dev/ptyxx
134 for masters and /dev/ttyxx for slaves of pseudo
135 terminals. This scheme has a number of problems, including
136 security. This option enables these legacy devices; on most
137 systems, it is safe to say N.
138
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -0800139config LEGACY_PTY_COUNT
140 int "Maximum number of legacy PTY in use"
141 depends on LEGACY_PTYS
142 range 0 256
143 default "256"
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900144 help
Greg Kroah-Hartmanbdcffc52011-02-22 15:41:47 -0800145 The maximum number of legacy PTYs that can be used at any one time.
146 The default is 256, and should be more than enough. Embedded
147 systems may want to reduce this to save memory.
148
149 When not in use, each legacy PTY occupies 12 bytes on 32-bit
150 architectures and 24 bytes on 64-bit architectures.
151
Kees Cook83efeee2022-10-22 11:29:49 -0700152config LEGACY_TIOCSTI
153 bool "Allow legacy TIOCSTI usage"
154 default y
155 help
156 Historically the kernel has allowed TIOCSTI, which will push
157 characters into a controlling TTY. This continues to be used
158 as a malicious privilege escalation mechanism, and provides no
159 meaningful real-world utility any more. Its use is considered
160 a dangerous legacy operation, and can be disabled on most
161 systems.
162
163 Say 'Y here only if you have confirmed that your system's
164 userspace depends on this functionality to continue operating
165 normally.
166
167 This functionality can be changed at runtime with the
168 dev.tty.legacy_tiocsti sysctl. This configuration option sets
169 the default value of the sysctl.
170
Randy Dunlap2cca6082020-03-11 15:57:36 -0700171config LDISC_AUTOLOAD
172 bool "Automatically load TTY Line Disciplines"
173 default y
174 help
175 Historically the kernel has always automatically loaded any
176 line discipline that is in a kernel module when a user asks
177 for it to be loaded with the TIOCSETD ioctl, or through other
178 means. This is not always the best thing to do on systems
179 where you know you will not be using some of the more
180 "ancient" line disciplines, so prevent the kernel from doing
181 this unless the request is coming from a process with the
182 CAP_SYS_MODULE permissions.
183
184 Say 'Y' here if you trust your userspace users to do the right
185 thing, or if you have only provided the line disciplines that
186 you know you will be using, or if you wish to continue to use
187 the traditional method of on-demand loading of these modules
188 by any user.
189
190 This functionality can be changed at runtime with the
191 dev.tty.ldisc_autoload sysctl, this configuration option will
192 only set the default value of this functionality.
193
194source "drivers/tty/serial/Kconfig"
195
Greg Kroah-Hartmana6afd9f2011-02-22 16:14:56 -0800196config SERIAL_NONSTANDARD
197 bool "Non-standard serial port support"
198 depends on HAS_IOMEM
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900199 help
Greg Kroah-Hartmana6afd9f2011-02-22 16:14:56 -0800200 Say Y here if you have any non-standard serial boards -- boards
201 which aren't supported using the standard "dumb" serial driver.
Jiri Slabyf76edd82021-03-02 07:21:35 +0100202 This includes intelligent serial boards such as
Greg Kroah-Hartmana6afd9f2011-02-22 16:14:56 -0800203 Digiboards, etc. These are usually used for systems that need many
204 serial ports because they serve many terminals or dial-in
205 connections.
206
207 Note that the answer to this question won't directly affect the
208 kernel: saying N will just cause the configurator to skip all
209 the questions about non-standard serial boards.
210
211 Most people can say N here.
212
Greg Kroah-Hartmana6afd9f2011-02-22 16:14:56 -0800213config MOXA_INTELLIO
214 tristate "Moxa Intellio support"
215 depends on SERIAL_NONSTANDARD && (ISA || EISA || PCI)
216 select FW_LOADER
217 help
218 Say Y here if you have a Moxa Intellio multiport serial card.
219
220 To compile this driver as a module, choose M here: the
221 module will be called moxa.
222
223config MOXA_SMARTIO
224 tristate "Moxa SmartIO support v. 2.0"
Jiri Slaby29134362021-06-18 08:14:07 +0200225 depends on SERIAL_NONSTANDARD && PCI
Greg Kroah-Hartmana6afd9f2011-02-22 16:14:56 -0800226 help
227 Say Y here if you have a Moxa SmartIO multiport serial card and/or
228 want to help develop a new version of this driver.
229
230 This is upgraded (1.9.1) driver from original Moxa drivers with
231 changes finally resulting in PCI probing.
232
233 This driver can also be built as a module. The module will be called
234 mxser. If you want to do that, say M here.
235
Greg Kroah-Hartmana6afd9f2011-02-22 16:14:56 -0800236config SYNCLINK_GT
237 tristate "SyncLink GT/AC support"
238 depends on SERIAL_NONSTANDARD && PCI
239 help
240 Support for SyncLink GT and SyncLink AC families of
241 synchronous and asynchronous serial adapters
242 manufactured by Microgate Systems, Ltd. (www.microgate.com)
243
Greg Kroah-Hartmana6afd9f2011-02-22 16:14:56 -0800244config N_HDLC
245 tristate "HDLC line discipline support"
246 depends on SERIAL_NONSTANDARD
247 help
248 Allows synchronous HDLC communications with tty device drivers that
249 support synchronous HDLC such as the Microgate SyncLink adapter.
250
251 This driver can be built as a module ( = code which can be
252 inserted in and removed from the running kernel whenever you want).
253 The module will be called n_hdlc. If you want to do that, say M
254 here.
255
Timur Tabidcd83aa2011-07-08 19:06:12 -0500256config PPC_EPAPR_HV_BYTECHAN
Anton Blancharda183d3a2013-12-09 16:03:10 +1100257 bool "ePAPR hypervisor byte channel driver"
Timur Tabidcd83aa2011-07-08 19:06:12 -0500258 depends on PPC
Stuart Yoder40656392012-07-03 05:48:54 +0000259 select EPAPR_PARAVIRT
Timur Tabidcd83aa2011-07-08 19:06:12 -0500260 help
261 This driver creates /dev entries for each ePAPR hypervisor byte
262 channel, thereby allowing applications to communicate with byte
263 channels as if they were serial ports.
264
265config PPC_EARLY_DEBUG_EHV_BC
266 bool "Early console (udbg) support for ePAPR hypervisors"
Stephen Rothwellf21c6d42012-02-20 07:22:38 +1100267 depends on PPC_EPAPR_HV_BYTECHAN=y
Timur Tabidcd83aa2011-07-08 19:06:12 -0500268 help
269 Select this option to enable early console (a.k.a. "udbg") support
270 via an ePAPR byte channel. You also need to choose the byte channel
271 handle below.
272
273config PPC_EARLY_DEBUG_EHV_BC_HANDLE
274 int "Byte channel handle for early console (udbg)"
275 depends on PPC_EARLY_DEBUG_EHV_BC
276 default 0
277 help
278 If you want early console (udbg) output through a byte channel,
279 specify the handle of the byte channel to use.
280
281 For this to work, the byte channel driver must be compiled
282 in-kernel, not as a module.
283
284 Note that only one early console driver can be enabled, so don't
285 enable any others if you enable this one.
286
287 If the number you specify is not a valid byte channel handle, then
288 there simply will be no early console output. This is true also
289 if you don't boot under a hypervisor at all.
Joe Millenbach4f73bc42013-01-17 22:44:22 -0800290
Arve Hjønnevåg666b7792013-01-21 23:38:47 +0000291config GOLDFISH_TTY
292 tristate "Goldfish TTY Driver"
293 depends on GOLDFISH
Miodrag Dinic3840ed92017-08-29 15:53:20 +0200294 select SERIAL_CORE
295 select SERIAL_CORE_CONSOLE
Arve Hjønnevåg666b7792013-01-21 23:38:47 +0000296 help
297 Console and system TTY driver for the Goldfish virtual platform.
298
Sebastian Andrzej Siewior6a28fd22017-11-30 09:16:31 +0100299config GOLDFISH_TTY_EARLY_CONSOLE
300 bool
301 default y if GOLDFISH_TTY=y
302 select SERIAL_EARLYCON
303
Randy Dunlap2cca6082020-03-11 15:57:36 -0700304config N_GSM
305 tristate "GSM MUX line discipline support (EXPERIMENTAL)"
306 depends on NET
307 help
308 This line discipline provides support for the GSM MUX protocol and
309 presents the mux as a set of 61 individual tty devices.
310
311config NOZOMI
312 tristate "HSDPA Broadband Wireless Data Card - Globe Trotter"
313 depends on PCI
314 help
315 If you have a HSDPA driver Broadband Wireless Data Card -
316 Globe Trotter PCMCIA card, say Y here.
317
318 To compile this driver as a module, choose M here, the module
319 will be called nozomi.
320
James Hogan4cebec62015-01-29 11:14:12 +0000321config MIPS_EJTAG_FDC_TTY
322 bool "MIPS EJTAG Fast Debug Channel TTY"
323 depends on MIPS_CDMM
324 help
325 This enables a TTY and console on the MIPS EJTAG Fast Debug Channels,
326 if they are present. This can be useful when working with an EJTAG
327 probe which supports it, to get console output and a login prompt via
328 EJTAG without needing to connect a serial cable.
329
330 TTY devices are named e.g. ttyFDC3c2 (for FDC channel 2 of the FDC on
331 CPU3).
332
333 The console can be enabled with console=fdc1 (for FDC channel 1 on all
334 CPUs). Do not use the console unless there is a debug probe attached
335 to drain the FDC TX FIFO.
336
337 If unsure, say N.
338
James Hogane9349452015-01-29 11:14:13 +0000339config MIPS_EJTAG_FDC_EARLYCON
340 bool "Early FDC console"
341 depends on MIPS_EJTAG_FDC_TTY
342 help
343 This registers a console on FDC channel 1 very early during boot (from
344 MIPS arch code). This is useful for bring-up and debugging early boot
345 issues.
346
347 Do not enable unless there is a debug probe attached to drain the FDC
348 TX FIFO.
349
350 If unsure, say N.
351
James Hoganc2d7ef52015-01-29 11:14:14 +0000352config MIPS_EJTAG_FDC_KGDB
353 bool "Use KGDB over an FDC channel"
354 depends on MIPS_EJTAG_FDC_TTY && KGDB
355 default y
356 help
Krzysztof Kozlowski45009142019-11-20 21:38:43 +0800357 This enables the use of KGDB over an FDC channel, allowing KGDB to be
358 used remotely or when a serial port isn't available.
James Hoganc2d7ef52015-01-29 11:14:14 +0000359
360config MIPS_EJTAG_FDC_KGDB_CHAN
361 int "KGDB FDC channel"
362 depends on MIPS_EJTAG_FDC_KGDB
363 range 2 15
364 default 3
365 help
366 FDC channel number to use for KGDB.
367
Petr Mladeka91bd622021-01-08 12:48:47 +0100368config NULL_TTY
369 tristate "NULL TTY driver"
370 help
371 Say Y here if you want a NULL TTY which simply discards messages.
372
373 This is useful to allow userspace applications which expect a console
374 device to work without modifications even when no console is
375 available or desired.
376
377 In order to use this driver, you should redirect the console to this
378 TTY, or boot the kernel with console=ttynull.
379
380 If unsure, say N.
381
Jag Raman55bd2132017-08-15 17:02:57 -0400382config VCC
383 tristate "Sun Virtual Console Concentrator"
384 depends on SUN_LDOMS
385 help
386 Support for Sun logical domain consoles.
Greg Kroah-Hartman7c0cca72019-01-21 17:26:42 +0100387
Randy Dunlap00e37542020-03-11 15:57:35 -0700388source "drivers/tty/hvc/Kconfig"
389
Arnaud Pouliquen7c0408d2021-10-15 11:47:01 +0200390config RPMSG_TTY
391 tristate "RPMSG tty driver"
392 depends on RPMSG
393 help
394 Say y here to export rpmsg endpoints as tty devices, usually found
395 in /dev/ttyRPMSGx.
396 This makes it possible for user-space programs to send and receive
397 rpmsg messages as a standard tty protocol.
398
399 To compile this driver as a module, choose M here: the module will be
400 called rpmsg_tty.
401
Joe Millenbach4f73bc42013-01-17 22:44:22 -0800402endif # TTY
Randy Dunlap00e37542020-03-11 15:57:35 -0700403
404source "drivers/tty/serdev/Kconfig"