colibri_imx6: fix video stdout in default environment

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

diff --git a/doc/README.log b/doc/README.log
index 75350ecd41d754e67d592c054576bb742e87969e..1057981f452eda35a58f302e034bb742ca9cfb88 100644 (file)
--- a/doc/README.log
+++ b/doc/README.log
@@ -69,6 +69,21 @@ If CONFIG_LOG is not set, then no logging will be available.
 The above have SPL versions also, e.g. CONFIG_SPL_MAX_LOG_LEVEL.
 
 
+Temporary logging within a single file
+--------------------------------------
+
+Sometimes it is useful to turn on logging just in one file. You can use this:
+
+   #define LOG_DEBUG
+
+to enable building in of all logging statements in a single file. Put it at
+the top of the file, before any #includes.
+
+To actually get U-Boot to output this you need to also set the default logging
+level - e.g. set CONFIG_LOG_DEFAULT_LEVEL to 7 (LOGL_DEBUG) or more. Otherwise
+debug output is suppressed and will not be generated.
+
+
 Convenience functions
 ---------------------
 
@@ -132,7 +147,10 @@ several possible determinations for logging information, all of which can be
 enabled or disabled independently:
 
    console - goes to stdout
+   syslog - broadcast RFC 3164 messages to syslog servers on UDP port 514
 
+The syslog driver sends the value of environmental variable 'log_hostname' as
+HOSTNAME if available.
 
 Log format
 ----------