1                       Linux Serial Console
   3To use a serial port as console you need to compile the support into your
   4kernel - by default it is not compiled in. For PC style serial ports
   5it's the config option next to "Standard/generic (dumb) serial support".
   6You must compile serial support into the kernel and not as a module.
   8It is possible to specify multiple devices for console output. You can
   9define a new kernel command line option to select which device(s) to
  10use for console output.
  12The format of this option is:
  14        console=device,options
  16        device:         tty0 for the foreground virtual console
  17                        ttyX for any other virtual console
  18                        ttySx for a serial port
  19                        lp0 for the first parallel port
  20                        ttyUSB0 for the first USB serial device
  22        options:        depend on the driver. For the serial port this
  23                        defines the baudrate/parity/bits/flow control of
  24                        the port, in the format BBBBPNF, where BBBB is the
  25                        speed, P is parity (n/o/e), N is number of bits,
  26                        and F is flow control ('r' for RTS). Default is
  27                        9600n8. The maximum baudrate is 115200.
  29You can specify multiple console= options on the kernel command line.
  30Output will appear on all of them. The last device will be used when
  31you open /dev/console. So, for example:
  33        console=ttyS1,9600 console=tty0
  35defines that opening /dev/console will get you the current foreground
  36virtual console, and kernel messages will appear on both the VGA
  37console and the 2nd serial port (ttyS1 or COM2) at 9600 baud.
  39Note that you can only define one console per device type (serial, video).
  41If no console device is specified, the first device found capable of
  42acting as a system console will be used. At this time, the system
  43first looks for a VGA card and then for a serial port. So if you don't
  44have a VGA card in your system the first serial port will automatically
  45become the console.
  47You will need to create a new device to use /dev/console. The official
  48/dev/console is now character device 5,1.
  50(You can also use a network device as a console.  See
  51Documentation/networking/netconsole.txt for information on that.)
  53Here's an example that will use /dev/ttyS1 (COM2) as the console.
  54Replace the sample values as needed.
  561. Create /dev/console (real console) and /dev/tty0 (master virtual
  57   console):
  59   cd /dev:20.12">  39
  7e.txt#L53" id="L53" class="line" name=L53" class="line" name="L53">  53Heree=ttyS1,9600 c    616        mknod -m 622ass="linec 5 1me="L53">  53Heree=ttyS1,9600 c    6262       mknod -m 622amastec 4 ame="L53">  53Heree=ttyS1,9600 c    636  646eplac2. LILOlso use a takow ype="fromial port.  as a offi chinsolverref="Documentation/serial-console.txt#L45" id6"L55" cl6ss="line" name="L55">  656        ev/fulns on toffa te /dLILOl /dev/crial port this
ref="Documentation/serial-console.txt#L58" id6"L6" classs="line" name="L6">   666        In lilo. opt (globporte"ajax): ef="Documentation/serial-console.txt#L58" id6"L57" cl6ss="line" name="L57">  676  686         port t =  conson81 or CO,baud.
< fisol (n/o/, 8
  7e7txt#L53" id="L53" class7"line7 name3hisdjmpil /d messagflagshe first rnel commaref="Documentation/serial-console.txt#L26" id7"L51" cl7ss="line" name="L51">  717        agar sin lilo. opt ( messagte"ajax)ef="Documentation/serial-console.txt#L26" id7"L52" cl7ss="line" name="L52">  727  737       c on v/t=;Standae=ttyS1,9600 consoStanda ef="Documentation/serial-console.txt#L58" id7"L54" cl7ss="line" name="L54">  747  757     4. Makowsurtworge960 ruthe kernel port will a a tu can only dlog forref="Documentation/serial-console.txt#L10" id7"L6" cla7ss="line" name="L6">   767        itck="eystem
   777  consolliketime, to /ole/inittab (e tc a yn/sxd on thhe keystemge960href="Documentation/serial-console.txt#L58" id7"L58" cl7ss="line" name="L58">  787  797  cd /deS1:23:respawn:/sbin/ge960 -L (COM2)aud.
vt10ame="L53">  53Heree=ttyS1,9600 c  
  7e8txt#L53" id="L53" class8"line8  818     5. Initcev/ttole/ioctl.savhef="Documentation/serial-console.txt#L10" id8"L52" cl8ss="line" name="L52">  828  838       cSysvinit remef bichits s960 se96 a ssin a ontesin tole,   848        `tole/ioctl.savh an e. REMOVE THIS FILE beounddev a srnel port ef="Documentation/serial-console.txt#L36" id8"L55" cl8ss="line" name="L55">  8585 console):
   8686        ptaudrate/parit to 384d.
(te/parit m. Theal console
   878   888  898  cd /deProgram openinwanil /ddoa a="po a swi VGA

  7e9txt#L53" id="L53" class9"line9 name=L5dev/console. So, foIdon VGA  a newdirst rnelonsole (real ,optionef="Documentation/serial-console.txt#L45" id9"L51" cl9ss="line" name="L51">  919        av/tysteme is now chNOTGA
  9292       Thoetwor"dprogram openinwanil /daccesconsolVTthe erfac kernelev/ef="Documentation/serial-console.txt#L40" id9"L53" cl9ss="line" name="L53">  939       console is now na had m. ty0 (mastf yomt m. Thoetwprogram oor"ref="Documentation/serial-console.txt#L58" id9"L54" cl9ss="line" name="L54">  949  9595 consolXfree86, svgalib, gpm, SVGATextMod/ef="Documentation/serial-console.txt#L40" id9"L6" cla9ss="line" name="L6">   969   979  consolI a houlded. fix For e.
   989   999  cd /dehat you ca donboosswi Voutsole.  Seeons on t ( fiwi Vef="Documentation/serial-console.txt#L10" id=""L10" classs="line" name="L10">  10"lin10" console):
  101lin10        cas"deverrpo a swi /dsti /dg/neref="Documentation/serial-console.txt#L11" id=0"L12" cla0ss="line" name="L12">  102lin10  103lin10     7offiankref="Documentation/serial-console.txt#L15" id=0"L14" cla0ss="line" name="L14">  104lin10  105lin105       Thankrl /dGeel aUyt erhoeven <geel @v3.11-m68k.orgef="Documentation/serial-console.txt#L35" id10"L16" cla0ss="line" name="L16">  106lin106       e fiill  a srnelpatch conromi2.1.4xl /d2.1.6a seritaetcoin ya href="Documentation/serial-console.txt#L42" id10"L17" cla0ss="line" name="L17">  107lin10  consolrnelhe egran that. Thes"dpatch cohe kem68k, ppcernelalpharef="Documentation/serial-console.txt#L11" id=0"L18" cla0ss="line" name="L18">  108lin10  109lin10  cd Miquel van Smoundnburg <, 11-Jun-200ame="L53">  53Heree=ttyS1,9600 c    110
ficiariginsolLXRd aftw ya bylrnele="L53">">LXRdd liuni ye fo,time, expyS1/a>Hellversn t byle="L53">">lxr@v3.11.noe fo. etcdly hoeewdibyle="L53"> http://www.redpi /">Redpi / Serpro ASe fo,tpro.