[systemd-devel] [PATCH] logind: Do not fail display count if a device has no parent

[Mantas Mikulėnas]

udev_device_get_parent() may return NULL when the device doesn't have a
parent, as is the case with (for example) /sys/devices/virtual/drm/ttm.

Also, log an actual error message instead of "-12 displays connected".
---
 src/login/logind-action.c | 4 +++-
 src/login/logind-core.c   | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/login/logind-action.c b/src/login/logind-action.c
index ae7b350..1928f43 100644
--- a/src/login/logind-action.c
+++ b/src/login/logind-action.c
@@ -84,7 +84,9 @@ int manager_handle_action(
                  * treat like this under the assumption that there is
                  * no modern drm driver available. */
                 n = manager_count_displays(m);
-                if (n != 1) {
+                if (n < 0)
+                        log_warning("Display counting failed: %s", strerror(-n));
+                else if (n != 1) {
                         log_debug("Ignoring lid switch request, %i displays connected.", n);
                         return 0;
                 }
diff --git a/src/login/logind-core.c b/src/login/logind-core.c
index ca34d37..053d2ed 100644
--- a/src/login/logind-core.c
+++ b/src/login/logind-core.c
@@ -520,7 +520,7 @@ int manager_count_displays(Manager *m) {
 
                 p = udev_device_get_parent(d);
                 if (!p)
-                        return -ENOMEM;
+                        continue;
 
                 /* If the parent shares the same subsystem as the
                  * device we are looking at then it is a connector,
-- 
1.9.rc1