From: Anton Partanen
Subject: [PATCH] Allow retry after transient authentication unavailability

PAM_AUTHINFO_UNAVAIL is not necessarily permanent. In particular,
pam_fprintd returns it when an active verification is interrupted by system
suspend. Treat that result as a failed attempt so a later start request can
retry it. Continue to cache PAM_MODULE_UNKNOWN as permanent unavailability.
---
 greeter/pamauthenticator.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/greeter/pamauthenticator.cpp b/greeter/pamauthenticator.cpp
index e2011fd..bb2521f 100644
--- a/greeter/pamauthenticator.cpp
+++ b/greeter/pamauthenticator.cpp
@@ -176,7 +176,9 @@ void PamWorker::authenticate()
         pam_setcred(m_handle, PAM_REFRESH_CRED);
         /* ignore errors on refresh credentials. If this did not work we use the old ones. */
         Q_EMIT succeeded();
-    } else if (rc == PAM_AUTHINFO_UNAVAIL || rc == PAM_MODULE_UNKNOWN) {
+    } else if (rc == PAM_AUTHINFO_UNAVAIL) {
+        Q_EMIT failed();
+    } else if (rc == PAM_MODULE_UNKNOWN) {
         m_unavailable = true;
         Q_EMIT unavailabilityChanged(m_unavailable);
     } else {
--
2.51.0