diff --git a/src/ipc.c b/src/ipc.c
index dc953adc..759665fe 100644
--- a/src/ipc.c
+++ b/src/ipc.c
@@ -580,6 +580,10 @@ static void dump_bar_bindings(yajl_gen gen, Barconfig *config) {
 }
 
 static char *canonicalize_output_name(char *name) {
+    /* Do not canonicalize special output names. */
+    if (strcasecmp(name, "primary") == 0) {
+        return name;
+    }
     Output *output = get_output_by_name(name, false);
     return output ? output_primary_name(output) : name;
 }
diff --git a/testcases/t/538-i3bar-primary-output.t b/testcases/t/538-i3bar-primary-output.t
new file mode 100644
index 00000000..67fd1b6c
--- /dev/null
+++ b/testcases/t/538-i3bar-primary-output.t
@@ -0,0 +1,40 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • http://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • http://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • http://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# Tests that i3bars configured to use the primary output do not have
+# their output names canonicalized to something other than "primary".
+# Ticket: #2948
+# Bug still in: 4.14-93-ga3a7d04a
+use i3test i3_config => <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+
+fake-outputs 1024x768+0+0P
+
+bar {
+    output primary
+}
+EOT
+
+my $bars = i3->get_bar_config()->recv;
+is(@$bars, 1, 'one bar configured');
+
+my $bar_id = shift @$bars;
+
+my $bar_config = i3->get_bar_config($bar_id)->recv;
+is_deeply($bar_config->{outputs}, [ "primary" ], 'bar_config output is primary');
+
+done_testing;