acpibtn_notify: ignore duplicate ACPI lid transitions

A Dell Precision 5510 produces two _LID events when the lid is closed.
This results in acpibtn_notify() adding two sleep tasks.  The laptop
suspends and resumes successfully, but on resume the second sleep
task runs and it goes right back to sleep.  Making the lid transition
a no-op when the existing value matches new _LID value works around
the problem.  OK miod@ jcs@

diff --git a/sys/dev/acpi/acpibtn.c b/sys/dev/acpi/acpibtn.c
index d925485..a16cb32 100644 (file)
--- a/sys/dev/acpi/acpibtn.c
+++ b/sys/dev/acpi/acpibtn.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: acpibtn.c,v 1.49 2022/04/06 18:59:27 naddy Exp $ */
+/* $OpenBSD: acpibtn.c,v 1.50 2023/04/03 13:38:18 millert Exp $ */
 /*
  * Copyright (c) 2005 Marco Peereboom <marco@openbsd.org>
  *
@@ -232,6 +232,8 @@ acpibtn_notify(struct aml_node *node, int notify_type, void *arg)
                if (aml_evalinteger(sc->sc_acpi, sc->sc_devnode,
                    "_LID", 0, NULL, &lid))
                        return (0);
+               if (sc->sc_sens.value == lid)
+                       break;
                sc->sc_sens.value = lid;
 
                if (lid != 0)