diff --git a/runtime/doc/channel.txt b/runtime/doc/channel.txt
index ae90430..43862d8 100644
--- a/runtime/doc/channel.txt
+++ b/runtime/doc/channel.txt
@@ -1433,11 +1433,17 @@
     let opts = {}
     let opts.in_mode = 'lsp'
     let opts.out_mode = 'lsp'
+    let opts.err_mode = 'nl'
     let opts.out_cb = function('LspOutCallback')
     let opts.err_cb = function('LspErrCallback')
     let opts.exit_cb = function('LspExitCallback')
     let job = job_start(cmd, opts)
 
+Note that if a job outputs LSP messages on stdout and non-LSP messages on
+stderr, then the channel-callback function should handle both the message
+formats appropriately or you should use a separate callback function for
+"out_cb" and "err_cb" to handle them as shown above.
+
 To synchronously send a JSON-RPC request to the server, use the
 |ch_evalexpr()| function. This function will wait and return the decoded
 response message from the server. You can use either the |channel-timeout| or