Hi Fiona,
On Thu, May 16, 2024 at 3:43 AM Fiona Klute fiona.klute@gmx.de wrote:
This adds details that I would have liked to have readily available, in particular how to activate the network interface before enabling netconsole, and how to integrate netconsole so you can use the U-Boot prompt.
Signed-off-by: Fiona Klute fiona.klute@gmx.de
Changes in v2:
- Include stderr redirection
- Use 4 spaces instead of tabs for code block to avoid overflowing lines
doc/usage/netconsole.rst | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/doc/usage/netconsole.rst b/doc/usage/netconsole.rst index 2aa3b9ccc5..647f0c220b 100644 --- a/doc/usage/netconsole.rst +++ b/doc/usage/netconsole.rst @@ -18,7 +18,9 @@ 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. +configured by setting the 'ncoutport' environment variable. Note that +you need to set up the network interface (e.g. using DHCP) before it +can be used for network console.
For example, if your server IP is 192.168.1.1, you could use::
@@ -107,3 +109,32 @@ as follows:
Note that unlike the U-Boot implementation the Linux netconsole is unidirectional, i. e. you have console output only in Linux.
+Setup via environment +---------------------
+If persistent environment is enabled in your U-Boot configuration, you +can configure the network console using the environment. For example::
- => env set autoload no
- => env set hostname "u-boot"
- => env set bootdelay 5
- => env set nc 'dhcp; env set stdout nc; env set stderr nc; env set stdin nc'
- => env set ncip 192.168.1.1
- => env set preboot "${preboot}; run nc;"
- => env save
- => reset
+``autoload no`` tells the ``dhcp`` command to configure the network +interface without trying to load an image. ``hostname "u-boot"`` sets +the hostname to be sent in DHCP requests, so they are easy to +recognize in the DHCP server log. The command in ``nc`` calls ``dhcp`` +to make sure the network interface is set up before enabling +netconsole.
+Adding ``nc`` to ``preboot`` tells U-Boot to activate netconsole +before trying to find any boot options, so you can interact with it if +desired.
+``env save`` stores the settings persistently, and ``reset`` then
+triggers a fresh start that will use the changed settings.
2.43.0
Just for information, if the board uses static IP then the example would be slightly different. I usually use static IP and ping the netconsole server to make sure it is up. However, I think this DHCP example is good enough to show how to prepare and activate netconsole.
Reviewed-by: Tony Dinh mibodhi@gmail.com
All the best, Tony