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Document comconsole_port and comconsole_pcidev loader variables.

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MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2012-01-07 11:16:23 +00:00
parent 5d8aec9c02
commit a7e92fc91c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=229771
1 changed files with 38 additions and 1 deletions
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39
sys/boot/common/loader.8
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@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd December 27, 2011
.Dd January 7, 2012
.Dt LOADER 8
.Os
.Sh NAME
@ -419,6 +419,43 @@ was compiled.
Changes to the
.Va comconsole_speed
variable take effect immediately.
.It Va comconsole_port
Defines the base i/o port used to access console UART
(i386 and amd64 only).
If the variable is not set, its assumed value is 0x3F8, which
corresponds to PC port COM1, unless overriden by
.Va BOOT_COMCONSOLE_PORT
variable during the compilation of
.Nm .
Setting the
.Va comconsole_port
variable automatically set
.Va hw.uart.console
environment variable to provide a hint to kernel for location of the console.
Loader console is changed immediately after variable
.Va comconsole_port
is set.
.It Va comconsole_pcidev
Defines the location of a PCI device of the 'simple communication'
class to be used as the serial console UART (i386 and amd64 only).
The syntax of the variable is
.Li 'bus:device:function[:bar]' ,
where all members must be numeric, with possible
.Li 0x
prefix to indicate a hexadecimal value.
The
.Va bar
member is optional and assumed to be 0x10 if omitted.
The bar must decode i/o space.
Setting the variable
.Va comconsole_pcidev
automatically sets the variable
.Va comconsole_port
to the base of the selected bar, and hint
.Va hw.uart.console .
Loader console is changed immediately after variable
.Va comconsole_pcidev
is set.
.It Va console
Defines the current console or consoles.
Multiple consoles may be specified.