From a5c7e3bb704eca6794f27bc86253e86c56a26917 Mon Sep 17 00:00:00 2001
From: Guido van Rooij <guido@FreeBSD.org>
Date: Thu, 18 Mar 2004 21:10:11 +0000
Subject: [PATCH] Prevent the strange situation that after each load/unload of
 a ppbus device, the device is probed multiple times (so each device is
 detected N times after unloading/loading the module N-1 times).

The real fix is (quote Doug and Warner):
> : In an ideal world, there should be some kind of BUS_UNIDENTIFY method
> : which a driver could use to delete the devices it created in
> : BUS_IDENTIFY.
>
> Or the bus would have a driver deleted routine that got called and it
> would remove all instances of the devclass attached to it.

Reviewed by:	Doug Rabson & Warner Losh
---
 sys/dev/ppbus/if_plip.c  | 5 ++++-
 sys/dev/ppbus/lpbb.c     | 6 +++++-
 sys/dev/ppbus/lpt.c      | 6 +++++-
 sys/dev/ppbus/pcfclock.c | 6 +++++-
 sys/dev/ppbus/ppi.c      | 6 +++++-
 sys/dev/ppbus/pps.c      | 6 +++++-
 sys/dev/ppbus/vpo.c      | 6 +++++-
 7 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/sys/dev/ppbus/if_plip.c b/sys/dev/ppbus/if_plip.c
index 32221c718f88..9805e0b05079 100644
--- a/sys/dev/ppbus/if_plip.c
+++ b/sys/dev/ppbus/if_plip.c
@@ -183,8 +183,11 @@ static devclass_t lp_devclass;
 static void
 lp_identify(driver_t *driver, device_t parent)
 {
+	device_t dev;
 
-	BUS_ADD_CHILD(parent, 0, "plip", -1);
+	dev = device_find_child(parent, "plip", 0);
+	if (!dev)
+		BUS_ADD_CHILD(parent, 0, "plip", -1);
 }
 /*
  * lpprobe()
diff --git a/sys/dev/ppbus/lpbb.c b/sys/dev/ppbus/lpbb.c
index 6516f503460f..a9b3667c4129 100644
--- a/sys/dev/ppbus/lpbb.c
+++ b/sys/dev/ppbus/lpbb.c
@@ -58,7 +58,11 @@ static void
 lpbb_identify(driver_t *driver, device_t parent)
 {
 
-	BUS_ADD_CHILD(parent, 0, "lpbb", -1);
+	device_t dev;
+
+	dev = device_find_child(parent, "lpbb", 0);
+	if (!dev)
+		BUS_ADD_CHILD(parent, 0, "lpbb", -1);
 }
 
 static int
diff --git a/sys/dev/ppbus/lpt.c b/sys/dev/ppbus/lpt.c
index f0bdea72e3d0..7855e364cc18 100644
--- a/sys/dev/ppbus/lpt.c
+++ b/sys/dev/ppbus/lpt.c
@@ -340,7 +340,11 @@ static void
 lpt_identify(driver_t *driver, device_t parent)
 {
 
-	BUS_ADD_CHILD(parent, 0, LPT_NAME, -1);
+	device_t dev;
+
+	dev = device_find_child(parent, LPT_NAME, 0);
+	if (!dev)
+		BUS_ADD_CHILD(parent, 0, LPT_NAME, -1);
 }
 
 /*
diff --git a/sys/dev/ppbus/pcfclock.c b/sys/dev/ppbus/pcfclock.c
index fd4c010d66f2..a47f304b5ecb 100644
--- a/sys/dev/ppbus/pcfclock.c
+++ b/sys/dev/ppbus/pcfclock.c
@@ -117,7 +117,11 @@ static void
 pcfclock_identify(driver_t *driver, device_t parent)
 {
 
-	BUS_ADD_CHILD(parent, 0, PCFCLOCK_NAME, -1);
+	device_t dev;
+
+	dev = device_find_child(parent, PCFCLOCK_NAME, 0);
+	if (!dev)
+		BUS_ADD_CHILD(parent, 0, PCFCLOCK_NAME, -1);
 }
 
 static int
diff --git a/sys/dev/ppbus/ppi.c b/sys/dev/ppbus/ppi.c
index 7df5851ca03a..113448db5129 100644
--- a/sys/dev/ppbus/ppi.c
+++ b/sys/dev/ppbus/ppi.c
@@ -133,7 +133,11 @@ static void
 ppi_identify(driver_t *driver, device_t parent)
 {
 
-	BUS_ADD_CHILD(parent, 0, "ppi", -1);
+	device_t dev;
+
+	dev = device_find_child(parent, "ppi", 0);
+	if (!dev)
+		BUS_ADD_CHILD(parent, 0, "ppi", -1);
 }
 
 /*
diff --git a/sys/dev/ppbus/pps.c b/sys/dev/ppbus/pps.c
index 20a8b02e7054..fef615769ea2 100644
--- a/sys/dev/ppbus/pps.c
+++ b/sys/dev/ppbus/pps.c
@@ -75,7 +75,11 @@ static void
 ppsidentify(driver_t *driver, device_t parent)
 {
 
-	BUS_ADD_CHILD(parent, 0, PPS_NAME, -1);
+	device_t dev;
+
+	dev = device_find_child(parent, PPS_NAME, 0);
+	if (!dev)
+		BUS_ADD_CHILD(parent, 0, PPS_NAME, -1);
 }
 
 static int
diff --git a/sys/dev/ppbus/vpo.c b/sys/dev/ppbus/vpo.c
index 69d2870403da..50ebf8135438 100644
--- a/sys/dev/ppbus/vpo.c
+++ b/sys/dev/ppbus/vpo.c
@@ -90,7 +90,11 @@ static void
 vpo_identify(driver_t *driver, device_t parent)
 {
 
-	BUS_ADD_CHILD(parent, 0, "vpo", -1);
+	device_t dev;
+
+	dev = device_find_child(parent, "vpo", 0);
+	if (!dev)
+		BUS_ADD_CHILD(parent, 0, "vpo", -1);
 }
 
 /*