[gnome-settings-daemon] smartcard: filter out spurious errors

[Ray Strode <halfline src gnome org>]

commit d4fce8369e0f50254a42bc7b426b9af4c7fc10b3
Author: Ray Strode <rstrode redhat com>
Date:   Tue Feb 11 10:11:51 2014 -0500

    smartcard: filter out spurious errors
    
    Some PKCS11 modules send spurious errors when the card is first
    powered on.  This commit works around that problem by adding
    retries.
    
    This brings us back to status quo with the old smartcard plugin.

 plugins/smartcard/gsd-smartcard-manager.c |   27 +++++++++++++++++++--------
 1 files changed, 19 insertions(+), 8 deletions(-)
---
diff --git a/plugins/smartcard/gsd-smartcard-manager.c b/plugins/smartcard/gsd-smartcard-manager.c
index 5601d84..b1fd52c 100644
--- a/plugins/smartcard/gsd-smartcard-manager.c
+++ b/plugins/smartcard/gsd-smartcard-manager.c
@@ -151,6 +151,7 @@ typedef struct
 {
         SECMODModule *driver;
         GHashTable *smartcards;
+        int number_of_consecutive_errors;
 } WatchSmartcardsOperation;
 
 static void
@@ -191,16 +192,26 @@ watch_one_event_from_driver (GsdSmartcardManager       *self,
 
                 error_code = PORT_GetError ();
 
-                g_warning ("smartcard event function failed.");
+                operation->number_of_consecutive_errors++;
+                if (operation->number_of_consecutive_errors > 10) {
+                     g_warning ("Got %d consecutive smartcard errors, so giving up.",
+                                operation->number_of_consecutive_errors);
+
+                     g_set_error (error,
+                                  GSD_SMARTCARD_MANAGER_ERROR,
+                                  GSD_SMARTCARD_MANAGER_ERROR_WITH_NSS,
+                                  "encountered unexpected error while "
+                                  "waiting for smartcard events (error %x)",
+                                  error_code);
+                     return FALSE;
+                }
 
-                g_set_error (error,
-                             GSD_SMARTCARD_MANAGER_ERROR,
-                             GSD_SMARTCARD_MANAGER_ERROR_WITH_NSS,
-                             "encountered unexpected error while "
-                             "waiting for smartcard events (error %d)",
-                             error_code);
-                return FALSE;
+                g_warning ("Got potentially spurious smartcard event error: %x.", error_code);
+
+                g_usleep (0.5 * G_USEC_PER_SEC);
+                return TRUE;
         }
+        operation->number_of_consecutive_errors = 0;
 
         slot_id = PK11_GetSlotID (card);
         slot_series = PK11_GetSlotSeries (card);