mac802154: change frame_retries behaviour

This change “mac802154: change frame_retries behaviour” in Linux kernel is authored by Alexander Aring <alex.aring [at] gmail.com> on Mon Aug 10 21:15:56 2015 +0200.

mac802154: change frame_retries behaviour

This patch changes the default minimum value of frame_retries to 0 and
changes the frame_retries default value to 3 which is also 802.15.4
default.

We don't use the frame_retries "-1" value as indicator for no-aret mode
anymore, instead we checking on the ack request bit inside the 802.15.4
frame control field. This allows a acknowledge handling per frame. This
checking is done by transceiver or inside xmit callback of driver layer.

If a transceiver doesn't support ARET handling the transmit
functionality ignores ack frames then, which isn't well but should not
effect anything of current functionality.

Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit 89c7d78.

There are 12 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 net/mac802154/iface.c | 3 +--
 net/mac802154/main.c  | 9 +++------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/net/mac802154/iface.c b/net/mac802154/iface.c
index ff99055..ed26952 100644
--- a/net/mac802154/iface.c
+++ b/net/mac802154/iface.c
@@ -498,8 +498,7 @@ static void ieee802154_if_setup(struct net_device *dev)
 	wpan_dev->min_be = 3;
 	wpan_dev->max_be = 5;
 	wpan_dev->csma_retries = 4;
-	/* for compatibility, actual default is 3 */
-	wpan_dev->frame_retries = -1;
+	wpan_dev->frame_retries = 3;
 
 	wpan_dev->pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
 	wpan_dev->short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
diff --git a/net/mac802154/main.c b/net/mac802154/main.c
index 9e55431..e8cab5b 100644
--- a/net/mac802154/main.c
+++ b/net/mac802154/main.c
@@ -111,7 +111,7 @@ struct ieee802154_hw *
 	phy->supported.max_minbe = 8;
 	phy->supported.min_maxbe = 3;
 	phy->supported.max_maxbe = 8;
-	phy->supported.min_frame_retries = -1;
+	phy->supported.min_frame_retries = 0;
 	phy->supported.max_frame_retries = 7;
 	phy->supported.max_csma_backoffs = 5;
 	phy->supported.lbt = NL802154_SUPPORTED_BOOL_FALSE;
@@ -177,11 +177,8 @@ int ieee802154_register_hw(struct ieee802154_hw *hw)
 	}
 
 	if (!(hw->flags & IEEE802154_HW_FRAME_RETRIES)) {
-		/* TODO should be 3, but our default value is -1 which means
-		 * no ARET handling.
-		 */
-		local->phy->supported.min_frame_retries = -1;
-		local->phy->supported.max_frame_retries = -1;
+		local->phy->supported.min_frame_retries = 3;
+		local->phy->supported.max_frame_retries = 3;
 	}
 
 	if (hw->flags & IEEE802154_HW_PROMISCUOUS)

The commit for this change in Linux stable tree is 89c7d78 (patch).

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