doc: mention kernel command line option loglevel=7
This is needed since when support for debugging Finit and the
kernel independently was added.
@@ -10,7 +10,7 @@ The `bool` setting is one of `on, off, true false, 1, 0`.
> parameters to init. E.g., `init=/sbin/finit -- finit.debug rescue`
* `debug`: Enable kernel debug. Debug messages are printed to the
- console until Finit starts up.
+ console until Finit starts up, unless `loglevel=7` (below) is used.
* `finit.debug[=bool]`: Enable finit debug. This is operated
independently of the kernel debug setting. New as of Finit v4.
@@ -26,11 +26,18 @@ The `bool` setting is one of `on, off, true false, 1, 0`.
signals and has no job control. Recommend using, and modifying,
`rescue` mode instead.
+* `loglevel=<0-7>`, sets the kernel's log level, which is more granular
+ than `debug`. Also, when `loglevel=7`, Finit will *not disable*
+ kernel logs to the console. This is very useful when debugging the
+ kernel at system bring-up. Since `loglevel=7` is the same as `debug`
+ this means you have to use `quiet` for a quiet boot, until sysklogd
+ takes over logging of kernel events.
+
* `panic=SEC`: By default the kernel does not reboot after a kernel
panic. This setting will cause a kernel reboot after SEC seconds.
* `quiet`: Suppress kernel logging to console, except for warnings and
- errors.
+ errors. Also, see `loglevel` and `quiet` above.
* `rescue`: Start rescue/maintenance mode. If your system comes with
the bundled `sulogin` program (Finit, or from util-linux/Busybox),
