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. 139 140 141config LEGACY_PTY_COUNT 142 int "Maximum number of legacy PTY in use" 143 depends on LEGACY_PTYS 144 range 0 256 145 default "256" 146 ---help--- 147 The maximum number of legacy PTYs that can be used at any one time. 148 The default is 256, and should be more than enough. Embedded 149 systems may want to reduce this to save memory. 150 151 When not in use, each legacy PTY occupies 12 bytes on 32-bit 152 architectures and 24 bytes on 64-bit architectures. 153 154config SERIAL_NONSTANDARD 155 bool "Non-standard serial port support" 156 depends on HAS_IOMEM 157 ---help--- 158 Say Y here if you have any non-standard serial boards -- boards 159 which aren't supported using the standard "dumb" serial driver. 160 This includes intelligent serial boards such as Cyclades, 161 Digiboards, etc. These are usually used for systems that need many 162 serial ports because they serve many terminals or dial-in 163 connections. 164 165 Note that the answer to this question won't directly affect the 166 kernel: saying N will just cause the configurator to skip all 167 the questions about non-standard serial boards. 168 169 Most people can say N here. 170 171config ROCKETPORT 172 tristate "Comtrol RocketPort support" 173 depends on SERIAL_NONSTANDARD && (ISA || EISA || PCI) 174 help 175 This driver supports Comtrol RocketPort and RocketModem PCI boards. 176 These boards provide 2, 4, 8, 16, or 32 high-speed serial ports or 177 modems. For information about the RocketPort/RocketModem boards 178 and this driver read <file:Documentation/driver-api/serial/rocket.rst>. 179 180 To compile this driver as a module, choose M here: the 181 module will be called rocket. 182 183 If you want to compile this driver into the kernel, say Y here. If 184 you don't have a Comtrol RocketPort/RocketModem card installed, say N. 185 186config CYCLADES 187 tristate "Cyclades async mux support" 188 depends on SERIAL_NONSTANDARD && (PCI || ISA) 189 select FW_LOADER 190 ---help--- 191 This driver supports Cyclades Z and Y multiserial boards. 192 You would need something like this to connect more than two modems to 193 your Linux box, for instance in order to become a dial-in server. 194 195 For information about the Cyclades-Z card, read 196 <file:Documentation/driver-api/serial/cyclades_z.rst>. 197 198 To compile this driver as a module, choose M here: the 199 module will be called cyclades. 200 201 If you haven't heard about it, it's safe to say N. 202 203config CYZ_INTR 204 bool "Cyclades-Z interrupt mode operation" 205 depends on CYCLADES && PCI 206 help 207 The Cyclades-Z family of multiport cards allows 2 (two) driver op 208 modes: polling and interrupt. In polling mode, the driver will check 209 the status of the Cyclades-Z ports every certain amount of time 210 (which is called polling cycle and is configurable). In interrupt 211 mode, it will use an interrupt line (IRQ) in order to check the 212 status of the Cyclades-Z ports. The default op mode is polling. If 213 unsure, say N. 214 215config MOXA_INTELLIO 216 tristate "Moxa Intellio support" 217 depends on SERIAL_NONSTANDARD && (ISA || EISA || PCI) 218 select FW_LOADER 219 help 220 Say Y here if you have a Moxa Intellio multiport serial card. 221 222 To compile this driver as a module, choose M here: the 223 module will be called moxa. 224 225config MOXA_SMARTIO 226 tristate "Moxa SmartIO support v. 2.0" 227 depends on SERIAL_NONSTANDARD && (PCI || EISA || ISA) 228 help 229 Say Y here if you have a Moxa SmartIO multiport serial card and/or 230 want to help develop a new version of this driver. 231 232 This is upgraded (1.9.1) driver from original Moxa drivers with 233 changes finally resulting in PCI probing. 234 235 This driver can also be built as a module. The module will be called 236 mxser. If you want to do that, say M here. 237 238config SYNCLINK 239 tristate "Microgate SyncLink card support" 240 depends on SERIAL_NONSTANDARD && PCI && ISA_DMA_API 241 help 242 Provides support for the SyncLink ISA and PCI multiprotocol serial 243 adapters. These adapters support asynchronous and HDLC bit 244 synchronous communication up to 10Mbps (PCI adapter). 245 246 This driver can only be built as a module ( = code which can be 247 inserted in and removed from the running kernel whenever you want). 248 The module will be called synclink. If you want to do that, say M 249 here. 250 251config SYNCLINKMP 252 tristate "SyncLink Multiport support" 253 depends on SERIAL_NONSTANDARD && PCI 254 help 255 Enable support for the SyncLink Multiport (2 or 4 ports) 256 serial adapter, running asynchronous and HDLC communications up 257 to 2.048Mbps. Each ports is independently selectable for 258 RS-232, V.35, RS-449, RS-530, and X.21 259 260 This driver may be built as a module ( = code which can be 261 inserted in and removed from the running kernel whenever you want). 262 The module will be called synclinkmp. If you want to do that, say M 263 here. 264 265config SYNCLINK_GT 266 tristate "SyncLink GT/AC support" 267 depends on SERIAL_NONSTANDARD && PCI 268 help 269 Support for SyncLink GT and SyncLink AC families of 270 synchronous and asynchronous serial adapters 271 manufactured by Microgate Systems, Ltd. (www.microgate.com) 272 273config NOZOMI 274 tristate "HSDPA Broadband Wireless Data Card - Globe Trotter" 275 depends on PCI 276 help 277 If you have a HSDPA driver Broadband Wireless Data Card - 278 Globe Trotter PCMCIA card, say Y here. 279 280 To compile this driver as a module, choose M here, the module 281 will be called nozomi. 282 283config ISI 284 tristate "Multi-Tech multiport card support" 285 depends on SERIAL_NONSTANDARD && PCI 286 select FW_LOADER 287 help 288 This is a driver for the Multi-Tech cards which provide several 289 serial ports. The driver is experimental and can currently only be 290 built as a module. The module will be called isicom. 291 If you want to do that, choose M here. 292 293config N_HDLC 294 tristate "HDLC line discipline support" 295 depends on SERIAL_NONSTANDARD 296 help 297 Allows synchronous HDLC communications with tty device drivers that 298 support synchronous HDLC such as the Microgate SyncLink adapter. 299 300 This driver can be built as a module ( = code which can be 301 inserted in and removed from the running kernel whenever you want). 302 The module will be called n_hdlc. If you want to do that, say M 303 here. 304 305config N_GSM 306 tristate "GSM MUX line discipline support (EXPERIMENTAL)" 307 depends on NET 308 help 309 This line discipline provides support for the GSM MUX protocol and 310 presents the mux as a set of 61 individual tty devices. 311 312config TRACE_ROUTER 313 tristate "Trace data router for MIPI P1149.7 cJTAG standard" 314 depends on TRACE_SINK 315 help 316 The trace router uses the Linux tty line discipline framework to 317 route trace data coming from a tty port (say UART for example) to 318 the trace sink line discipline driver and to another tty port (say 319 USB). This is part of a solution for the MIPI P1149.7, compact JTAG, 320 standard, which is for debugging mobile devices. The PTI driver in 321 drivers/misc/pti.c defines the majority of this MIPI solution. 322 323 You should select this driver if the target kernel is meant for 324 a mobile device containing a modem. Then you will need to select 325 "Trace data sink for MIPI P1149.7 cJTAG standard" line discipline 326 driver. 327 328config TRACE_SINK 329 tristate "Trace data sink for MIPI P1149.7 cJTAG standard" 330 help 331 The trace sink uses the Linux line discipline framework to receive 332 trace data coming from the trace router line discipline driver 333 to a user-defined tty port target, like USB. 334 This is to provide a way to extract modem trace data on 335 devices that do not have a PTI HW module, or just need modem 336 trace data to come out of a different HW output port. 337 This is part of a solution for the P1149.7, compact JTAG, standard. 338 339 If you select this option, you need to select 340 "Trace data router for MIPI P1149.7 cJTAG standard". 341 342config PPC_EPAPR_HV_BYTECHAN 343 bool "ePAPR hypervisor byte channel driver" 344 depends on PPC 345 select EPAPR_PARAVIRT 346 help 347 This driver creates /dev entries for each ePAPR hypervisor byte 348 channel, thereby allowing applications to communicate with byte 349 channels as if they were serial ports. 350 351config PPC_EARLY_DEBUG_EHV_BC 352 bool "Early console (udbg) support for ePAPR hypervisors" 353 depends on PPC_EPAPR_HV_BYTECHAN=y 354 help 355 Select this option to enable early console (a.k.a. "udbg") support 356 via an ePAPR byte channel. You also need to choose the byte channel 357 handle below. 358 359config PPC_EARLY_DEBUG_EHV_BC_HANDLE 360 int "Byte channel handle for early console (udbg)" 361 depends on PPC_EARLY_DEBUG_EHV_BC 362 default 0 363 help 364 If you want early console (udbg) output through a byte channel, 365 specify the handle of the byte channel to use. 366 367 For this to work, the byte channel driver must be compiled 368 in-kernel, not as a module. 369 370 Note that only one early console driver can be enabled, so don't 371 enable any others if you enable this one. 372 373 If the number you specify is not a valid byte channel handle, then 374 there simply will be no early console output. This is true also 375 if you don't boot under a hypervisor at all. 376 377config NULL_TTY 378 tristate "NULL TTY driver" 379 help 380 Say Y here if you want a NULL TTY which simply discards messages. 381 382 This is useful to allow userspace applications which expect a console 383 device to work without modifications even when no console is 384 available or desired. 385 386 In order to use this driver, you should redirect the console to this 387 TTY, or boot the kernel with console=ttynull. 388 389 If unsure, say N. 390 391config GOLDFISH_TTY 392 tristate "Goldfish TTY Driver" 393 depends on GOLDFISH 394 select SERIAL_CORE 395 select SERIAL_CORE_CONSOLE 396 help 397 Console and system TTY driver for the Goldfish virtual platform. 398 399config GOLDFISH_TTY_EARLY_CONSOLE 400 bool 401 default y if GOLDFISH_TTY=y 402 select SERIAL_EARLYCON 403 404config MIPS_EJTAG_FDC_TTY 405 bool "MIPS EJTAG Fast Debug Channel TTY" 406 depends on MIPS_CDMM 407 help 408 This enables a TTY and console on the MIPS EJTAG Fast Debug Channels, 409 if they are present. This can be useful when working with an EJTAG 410 probe which supports it, to get console output and a login prompt via 411 EJTAG without needing to connect a serial cable. 412 413 TTY devices are named e.g. ttyFDC3c2 (for FDC channel 2 of the FDC on 414 CPU3). 415 416 The console can be enabled with console=fdc1 (for FDC channel 1 on all 417 CPUs). Do not use the console unless there is a debug probe attached 418 to drain the FDC TX FIFO. 419 420 If unsure, say N. 421 422config MIPS_EJTAG_FDC_EARLYCON 423 bool "Early FDC console" 424 depends on MIPS_EJTAG_FDC_TTY 425 help 426 This registers a console on FDC channel 1 very early during boot (from 427 MIPS arch code). This is useful for bring-up and debugging early boot 428 issues. 429 430 Do not enable unless there is a debug probe attached to drain the FDC 431 TX FIFO. 432 433 If unsure, say N. 434 435config MIPS_EJTAG_FDC_KGDB 436 bool "Use KGDB over an FDC channel" 437 depends on MIPS_EJTAG_FDC_TTY && KGDB 438 default y 439 help 440 This enables the use of KGDB over an FDC channel, allowing KGDB to be 441 used remotely or when a serial port isn't available. 442 443config MIPS_EJTAG_FDC_KGDB_CHAN 444 int "KGDB FDC channel" 445 depends on MIPS_EJTAG_FDC_KGDB 446 range 2 15 447 default 3 448 help 449 FDC channel number to use for KGDB. 450 451config VCC 452 tristate "Sun Virtual Console Concentrator" 453 depends on SUN_LDOMS 454 help 455 Support for Sun logical domain consoles. 456 457config LDISC_AUTOLOAD 458 bool "Automatically load TTY Line Disciplines" 459 default y 460 help 461 Historically the kernel has always automatically loaded any 462 line discipline that is in a kernel module when a user asks 463 for it to be loaded with the TIOCSETD ioctl, or through other 464 means. This is not always the best thing to do on systems 465 where you know you will not be using some of the more 466 "ancient" line disciplines, so prevent the kernel from doing 467 this unless the request is coming from a process with the 468 CAP_SYS_MODULE permissions. 469 470 Say 'Y' here if you trust your userspace users to do the right 471 thing, or if you have only provided the line disciplines that 472 you know you will be using, or if you wish to continue to use 473 the traditional method of on-demand loading of these modules 474 by any user. 475 476 This functionality can be changed at runtime with the 477 dev.tty.ldisc_autoload sysctl, this configuration option will 478 only set the default value of this functionality. 479 480endif # TTY 481
