colibri_imx6: fix video stdout in default environment

[oweals/u-boot.git] / doc / README.NetConsole

diff --git a/doc/README.NetConsole b/doc/README.NetConsole
index 8dc0d29197ec0cba86a86a55d64638e137f1d65e..af7fc6043a3f3f02497f7527342b18551402be9d 100644 (file)
--- a/doc/README.NetConsole
+++ b/doc/README.NetConsole
@@ -6,18 +6,44 @@ serial and network input/output devices by adjusting the 'stdin' and
 set either of these variables to "nc". Input and output can be
 switched independently.
 
+CONFIG_NETCONSOLE_BUFFER_SIZE - Override the default buffer size
+
+We use an environment variable 'ncip' to set the IP address and the
+port of the destination. The format is <ip_addr>:<port>. If <port> is
+omitted, the value of 6666 is used. If the env var doesn't exist, the
+broadcast address and port 6666 are used. If it is set to an IP
+address of 0 (or 0.0.0.0) then no messages are sent to the network.
+The source / listening port can be configured separately by setting
+the 'ncinport' environment variable and the destination port can be
+configured by setting the 'ncoutport' environment variable.
+
+For example, if your server IP is 192.168.1.1, you could use:
+
+       => setenv nc 'setenv stdout nc;setenv stdin nc'
+       => setenv ncip 192.168.1.1
+       => saveenv
+       => run nc
+
+
 On the host side, please use this script to access the console:
 
-+++++++++++++++++++++++++++++++++++++++++++
-#! /bin/bash
+       tools/netconsole <ip> [port]
+
+The script uses netcat to talk to the board over UDP.  It requires you to
+specify the target IP address (or host name, assuming DNS is working). The
+script can be interrupted by pressing ^T (CTRL-T).
 
-TARGET_IP=$1
+Be aware that in some distributives (Fedora Core 5 at least)
+usage of nc has been changed and -l and -p options are considered
+as mutually exclusive. If nc complains about options provided,
+you can just remove the -p option from the script.
 
-stty -icanon -echo intr ^T
-nc -u -l -p 6666 < /dev/null &
-nc -u ${TARGET_IP} 6666
-stty icanon echo intr ^C
-+++++++++++++++++++++++++++++++++++++++++++
+It turns out that 'netcat' cannot be used to listen to broadcast
+packets. We developed our own tool 'ncb' (see tools directory) that
+listens to broadcast packets on a given port and dumps them to the
+standard output.  It will be built when compiling for a board which
+has CONFIG_NETCONSOLE defined.  If the netconsole script can find it
+in PATH or in the same directory, it will be used instead.
 
 For Linux, the network-based console needs special configuration.
 Minimally, the host IP address needs to be specified. This can be
@@ -66,3 +92,6 @@ To browse the Linux network console output, use the 'netcat' tool invoked
 as follows:
 
        nc -u -l -p 6666
+
+Note that unlike the U-Boot implementation the Linux netconsole is
+unidirectional, i. e. you have console output only in Linux.