1# SPDX-License-Identifier: GPL-2.0 2config TTY 3 bool "Enable TTY" if EXPERT 4 default y 5 help 6 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 13config VT 14 bool "Virtual terminal" if EXPERT 15 depends on !UML 16 select INPUT 17 default y 18 help 19 If you say Y here, you will get support for terminal devices with 20 display and keyboard devices. These are called "virtual" because you 21 can run several virtual terminals (also called virtual consoles) on 22 one physical terminal. This is rather useful, for example one 23 virtual terminal can collect system messages and warnings, another 24 one can be used for a text-mode user session, and a third could run 25 an X session, all in parallel. Switching between virtual terminals 26 is done with certain key combinations, usually Alt-<function key>. 27 28 The setterm command ("man setterm") can be used to change the 29 properties (such as colors or beeping) of a virtual terminal. The 30 man page console_codes(4) ("man console_codes") contains the special 31 character sequences that can be used to change those properties 32 directly. The fonts used on virtual terminals can be changed with 33 the setfont ("man setfont") command and the key bindings are defined 34 with the loadkeys ("man loadkeys") command. 35 36 You need at least one virtual terminal device in order to make use 37 of your keyboard and monitor. Therefore, only people configuring an 38 embedded system would want to say N here in order to save some 39 memory; the only way to log into such a system is then via a serial 40 or network connection. 41 42 If unsure, say Y, or else you won't be able to do much with your new 43 shiny Linux system :-) 44 45config CONSOLE_TRANSLATIONS 46 depends on VT 47 default y 48 bool "Enable character translations in console" if EXPERT 49 help 50 This enables support for font mapping and Unicode translation 51 on virtual consoles. 52 53config VT_CONSOLE 54 bool "Support for console on virtual terminal" if EXPERT 55 depends on VT 56 default y 57 help 58 The system console is the device which receives all kernel messages 59 and warnings and which allows logins in single user mode. If you 60 answer Y here, a virtual terminal (the device used to interact with 61 a physical terminal) can be used as system console. This is the most 62 common mode of operations, so you should say Y here unless you want 63 the kernel messages be output only to a serial port (in which case 64 you should say Y to "Console on serial port", below). 65 66 If you do say Y here, by default the currently visible virtual 67 terminal (/dev/tty0) will be used as system console. You can change 68 that with a kernel command line option such as "console=tty3" which 69 would use the third virtual terminal as system console. (Try "man 70 bootparam" or see the documentation of your boot loader (lilo or 71 loadlin) about how to pass options to the kernel at boot time.) 72 73 If unsure, say Y. 74 75config VT_CONSOLE_SLEEP 76 def_bool y 77 depends on VT_CONSOLE && PM_SLEEP 78 79config HW_CONSOLE 80 bool 81 depends on VT && !UML 82 default y 83 84config VT_HW_CONSOLE_BINDING 85 bool "Support for binding and unbinding console drivers" 86 depends on HW_CONSOLE 87 help 88 The virtual terminal is the device that interacts with the physical 89 terminal through console drivers. On these systems, at least one 90 console driver is loaded. In other configurations, additional console 91 drivers may be enabled, such as the framebuffer console. If more than 92 1 console driver is enabled, setting this to 'y' will allow you to 93 select the console driver that will serve as the backend for the 94 virtual terminals. 95 96 See <file:Documentation/driver-api/console.rst> for more 97 information. For framebuffer console users, please refer to 98 <file:Documentation/fb/fbcon.rst>. 99 100config UNIX98_PTYS 101 bool "Unix98 PTY support" if EXPERT 102 default y 103 help 104 A pseudo terminal (PTY) is a software device consisting of two 105 halves: a master and a slave. The slave device behaves identical to 106 a physical terminal; the master device is used by a process to 107 read data from and write data to the slave, thereby emulating a 108 terminal. Typical programs for the master side are telnet servers 109 and xterms. 110 111 Linux has traditionally used the BSD-like names /dev/ptyxx for 112 masters and /dev/ttyxx for slaves of pseudo terminals. This scheme 113 has a number of problems. The GNU C library glibc 2.1 and later, 114 however, supports the Unix98 naming standard: in order to acquire a 115 pseudo terminal, a process opens /dev/ptmx; the number of the pseudo 116 terminal is then made available to the process and the pseudo 117 terminal slave can be accessed as /dev/pts/<number>. What was 118 traditionally /dev/ttyp2 will then be /dev/pts/2, for example. 119 120 All modern Linux systems use the Unix98 ptys. Say Y unless 121 you're on an embedded system and want to conserve memory. 122 123config LEGACY_PTYS 124 bool "Legacy (BSD) PTY support" 125 default y 126 help 127 A pseudo terminal (PTY) is a software device consisting of two 128 halves: a master and a slave. The slave device behaves identical to 129 a physical terminal; the master device is used by a process to 130 read data from and write data to the slave, thereby emulating a 131 terminal. Typical programs for the master side are telnet servers 132 and xterms. 133 134 Linux has traditionally used the BSD-like names /dev/ptyxx 135 for masters and /dev/ttyxx for slaves of pseudo 136 terminals. This scheme has a number of problems, including 137 security. This option enables these legacy devices; on most 138 systems, it is safe to say N. 139 140config LEGACY_PTY_COUNT 141 int "Maximum number of legacy PTY in use" 142 depends on LEGACY_PTYS 143 range 0 256 144 default "256" 145 help 146 The maximum number of legacy PTYs that can be used at any one time. 147 The default is 256, and should be more than enough. Embedded 148 systems may want to reduce this to save memory. 149 150 When not in use, each legacy PTY occupies 12 bytes on 32-bit 151 architectures and 24 bytes on 64-bit architectures. 152 153config LDISC_AUTOLOAD 154 bool "Automatically load TTY Line Disciplines" 155 default y 156 help 157 Historically the kernel has always automatically loaded any 158 line discipline that is in a kernel module when a user asks 159 for it to be loaded with the TIOCSETD ioctl, or through other 160 means. This is not always the best thing to do on systems 161 where you know you will not be using some of the more 162 "ancient" line disciplines, so prevent the kernel from doing 163 this unless the request is coming from a process with the 164 CAP_SYS_MODULE permissions. 165 166 Say 'Y' here if you trust your userspace users to do the right 167 thing, or if you have only provided the line disciplines that 168 you know you will be using, or if you wish to continue to use 169 the traditional method of on-demand loading of these modules 170 by any user. 171 172 This functionality can be changed at runtime with the 173 dev.tty.ldisc_autoload sysctl, this configuration option will 174 only set the default value of this functionality. 175 176source "drivers/tty/serial/Kconfig" 177 178config SERIAL_NONSTANDARD 179 bool "Non-standard serial port support" 180 depends on HAS_IOMEM 181 help 182 Say Y here if you have any non-standard serial boards -- boards 183 which aren't supported using the standard "dumb" serial driver. 184 This includes intelligent serial boards such as Cyclades, 185 Digiboards, etc. These are usually used for systems that need many 186 serial ports because they serve many terminals or dial-in 187 connections. 188 189 Note that the answer to this question won't directly affect the 190 kernel: saying N will just cause the configurator to skip all 191 the questions about non-standard serial boards. 192 193 Most people can say N here. 194 195config ROCKETPORT 196 tristate "Comtrol RocketPort support" 197 depends on SERIAL_NONSTANDARD && (ISA || EISA || PCI) 198 help 199 This driver supports Comtrol RocketPort and RocketModem PCI boards. 200 These boards provide 2, 4, 8, 16, or 32 high-speed serial ports or 201 modems. For information about the RocketPort/RocketModem boards 202 and this driver read <file:Documentation/driver-api/serial/rocket.rst>. 203 204 To compile this driver as a module, choose M here: the 205 module will be called rocket. 206 207 If you want to compile this driver into the kernel, say Y here. If 208 you don't have a Comtrol RocketPort/RocketModem card installed, say N. 209 210config CYCLADES 211 tristate "Cyclades async mux support" 212 depends on SERIAL_NONSTANDARD && (PCI || ISA) 213 select FW_LOADER 214 help 215 This driver supports Cyclades Z and Y multiserial boards. 216 You would need something like this to connect more than two modems to 217 your Linux box, for instance in order to become a dial-in server. 218 219 For information about the Cyclades-Z card, read 220 <file:Documentation/driver-api/serial/cyclades_z.rst>. 221 222 To compile this driver as a module, choose M here: the 223 module will be called cyclades. 224 225 If you haven't heard about it, it's safe to say N. 226 227config CYZ_INTR 228 bool "Cyclades-Z interrupt mode operation" 229 depends on CYCLADES && PCI 230 help 231 The Cyclades-Z family of multiport cards allows 2 (two) driver op 232 modes: polling and interrupt. In polling mode, the driver will check 233 the status of the Cyclades-Z ports every certain amount of time 234 (which is called polling cycle and is configurable). In interrupt 235 mode, it will use an interrupt line (IRQ) in order to check the 236 status of the Cyclades-Z ports. The default op mode is polling. If 237 unsure, say N. 238 239config MOXA_INTELLIO 240 tristate "Moxa Intellio support" 241 depends on SERIAL_NONSTANDARD && (ISA || EISA || PCI) 242 select FW_LOADER 243 help 244 Say Y here if you have a Moxa Intellio multiport serial card. 245 246 To compile this driver as a module, choose M here: the 247 module will be called moxa. 248 249config MOXA_SMARTIO 250 tristate "Moxa SmartIO support v. 2.0" 251 depends on SERIAL_NONSTANDARD && (PCI || EISA || ISA) 252 help 253 Say Y here if you have a Moxa SmartIO multiport serial card and/or 254 want to help develop a new version of this driver. 255 256 This is upgraded (1.9.1) driver from original Moxa drivers with 257 changes finally resulting in PCI probing. 258 259 This driver can also be built as a module. The module will be called 260 mxser. If you want to do that, say M here. 261 262config SYNCLINK_GT 263 tristate "SyncLink GT/AC support" 264 depends on SERIAL_NONSTANDARD && PCI 265 help 266 Support for SyncLink GT and SyncLink AC families of 267 synchronous and asynchronous serial adapters 268 manufactured by Microgate Systems, Ltd. (www.microgate.com) 269 270config ISI 271 tristate "Multi-Tech multiport card support" 272 depends on SERIAL_NONSTANDARD && PCI 273 select FW_LOADER 274 help 275 This is a driver for the Multi-Tech cards which provide several 276 serial ports. The driver is experimental and can currently only be 277 built as a module. The module will be called isicom. 278 If you want to do that, choose M here. 279 280config N_HDLC 281 tristate "HDLC line discipline support" 282 depends on SERIAL_NONSTANDARD 283 help 284 Allows synchronous HDLC communications with tty device drivers that 285 support synchronous HDLC such as the Microgate SyncLink adapter. 286 287 This driver can be built as a module ( = code which can be 288 inserted in and removed from the running kernel whenever you want). 289 The module will be called n_hdlc. If you want to do that, say M 290 here. 291 292config PPC_EPAPR_HV_BYTECHAN 293 bool "ePAPR hypervisor byte channel driver" 294 depends on PPC 295 select EPAPR_PARAVIRT 296 help 297 This driver creates /dev entries for each ePAPR hypervisor byte 298 channel, thereby allowing applications to communicate with byte 299 channels as if they were serial ports. 300 301config PPC_EARLY_DEBUG_EHV_BC 302 bool "Early console (udbg) support for ePAPR hypervisors" 303 depends on PPC_EPAPR_HV_BYTECHAN=y 304 help 305 Select this option to enable early console (a.k.a. "udbg") support 306 via an ePAPR byte channel. You also need to choose the byte channel 307 handle below. 308 309config PPC_EARLY_DEBUG_EHV_BC_HANDLE 310 int "Byte channel handle for early console (udbg)" 311 depends on PPC_EARLY_DEBUG_EHV_BC 312 default 0 313 help 314 If you want early console (udbg) output through a byte channel, 315 specify the handle of the byte channel to use. 316 317 For this to work, the byte channel driver must be compiled 318 in-kernel, not as a module. 319 320 Note that only one early console driver can be enabled, so don't 321 enable any others if you enable this one. 322 323 If the number you specify is not a valid byte channel handle, then 324 there simply will be no early console output. This is true also 325 if you don't boot under a hypervisor at all. 326 327config GOLDFISH_TTY 328 tristate "Goldfish TTY Driver" 329 depends on GOLDFISH 330 select SERIAL_CORE 331 select SERIAL_CORE_CONSOLE 332 help 333 Console and system TTY driver for the Goldfish virtual platform. 334 335config GOLDFISH_TTY_EARLY_CONSOLE 336 bool 337 default y if GOLDFISH_TTY=y 338 select SERIAL_EARLYCON 339 340config N_GSM 341 tristate "GSM MUX line discipline support (EXPERIMENTAL)" 342 depends on NET 343 help 344 This line discipline provides support for the GSM MUX protocol and 345 presents the mux as a set of 61 individual tty devices. 346 347config NOZOMI 348 tristate "HSDPA Broadband Wireless Data Card - Globe Trotter" 349 depends on PCI 350 help 351 If you have a HSDPA driver Broadband Wireless Data Card - 352 Globe Trotter PCMCIA card, say Y here. 353 354 To compile this driver as a module, choose M here, the module 355 will be called nozomi. 356 357config MIPS_EJTAG_FDC_TTY 358 bool "MIPS EJTAG Fast Debug Channel TTY" 359 depends on MIPS_CDMM 360 help 361 This enables a TTY and console on the MIPS EJTAG Fast Debug Channels, 362 if they are present. This can be useful when working with an EJTAG 363 probe which supports it, to get console output and a login prompt via 364 EJTAG without needing to connect a serial cable. 365 366 TTY devices are named e.g. ttyFDC3c2 (for FDC channel 2 of the FDC on 367 CPU3). 368 369 The console can be enabled with console=fdc1 (for FDC channel 1 on all 370 CPUs). Do not use the console unless there is a debug probe attached 371 to drain the FDC TX FIFO. 372 373 If unsure, say N. 374 375config MIPS_EJTAG_FDC_EARLYCON 376 bool "Early FDC console" 377 depends on MIPS_EJTAG_FDC_TTY 378 help 379 This registers a console on FDC channel 1 very early during boot (from 380 MIPS arch code). This is useful for bring-up and debugging early boot 381 issues. 382 383 Do not enable unless there is a debug probe attached to drain the FDC 384 TX FIFO. 385 386 If unsure, say N. 387 388config MIPS_EJTAG_FDC_KGDB 389 bool "Use KGDB over an FDC channel" 390 depends on MIPS_EJTAG_FDC_TTY && KGDB 391 default y 392 help 393 This enables the use of KGDB over an FDC channel, allowing KGDB to be 394 used remotely or when a serial port isn't available. 395 396config MIPS_EJTAG_FDC_KGDB_CHAN 397 int "KGDB FDC channel" 398 depends on MIPS_EJTAG_FDC_KGDB 399 range 2 15 400 default 3 401 help 402 FDC channel number to use for KGDB. 403 404config TRACE_ROUTER 405 tristate "Trace data router for MIPI P1149.7 cJTAG standard" 406 depends on TRACE_SINK 407 help 408 The trace router uses the Linux tty line discipline framework to 409 route trace data coming from a tty port (say UART for example) to 410 the trace sink line discipline driver and to another tty port (say 411 USB). This is part of a solution for the MIPI P1149.7, compact JTAG, 412 standard, which is for debugging mobile devices. The PTI driver in 413 drivers/misc/pti.c defines the majority of this MIPI solution. 414 415 You should select this driver if the target kernel is meant for 416 a mobile device containing a modem. Then you will need to select 417 "Trace data sink for MIPI P1149.7 cJTAG standard" line discipline 418 driver. 419 420config TRACE_SINK 421 tristate "Trace data sink for MIPI P1149.7 cJTAG standard" 422 help 423 The trace sink uses the Linux line discipline framework to receive 424 trace data coming from the trace router line discipline driver 425 to a user-defined tty port target, like USB. 426 This is to provide a way to extract modem trace data on 427 devices that do not have a PTI HW module, or just need modem 428 trace data to come out of a different HW output port. 429 This is part of a solution for the P1149.7, compact JTAG, standard. 430 431 If you select this option, you need to select 432 "Trace data router for MIPI P1149.7 cJTAG standard". 433 434config VCC 435 tristate "Sun Virtual Console Concentrator" 436 depends on SUN_LDOMS 437 help 438 Support for Sun logical domain consoles. 439 440source "drivers/tty/hvc/Kconfig" 441 442endif # TTY 443 444source "drivers/tty/serdev/Kconfig" 445