rt2x00: do not generate seqno in h/w if QOS is disabled

This is workaround H/W or F/W bug, see in code comments. Without the fix
ping can receive duplicated ICMP frames while associated with legacy AP.

Reported-by: Walter Goldens <goldenstranger@yahoo.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 24 insertions, 2 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 8de9bfc4e51a..5583214721e0 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -693,6 +693,7 @@ enum rt2x00_state_flags {
         CONFIG_CHANNEL_HT40,
         CONFIG_POWERSAVING,
         CONFIG_HT_DISABLED,
+        CONFIG_QOS_DISABLED,
 
         /*
          * Mark we currently are sequentially reading TX_STA_FIFO register
diff --git a/drivers/net/wireless/rt2x00/rt2x00mac.c b/drivers/net/wireless/rt2x00/rt2x00mac.c
index 2df2eb6d3e06..b49773ef72f2 100644
--- a/drivers/net/wireless/rt2x00/rt2x00mac.c
+++ b/drivers/net/wireless/rt2x00/rt2x00mac.c
@@ -709,9 +709,19 @@ void rt2x00mac_bss_info_changed(struct ieee80211_hw *hw,
                         rt2x00dev->intf_associated--;
 
                 rt2x00leds_led_assoc(rt2x00dev, !!rt2x00dev->intf_associated);
+
+                clear_bit(CONFIG_QOS_DISABLED, &rt2x00dev->flags);
         }
 
         /*
+         * Check for access point which do not support 802.11e . We have to
+         * generate data frames sequence number in S/W for such AP, because
+         * of H/W bug.
+         */
+        if (changes & BSS_CHANGED_QOS && !bss_conf->qos)
+                set_bit(CONFIG_QOS_DISABLED, &rt2x00dev->flags);
+
+        /*
          * When the erp information has changed, we should perform
          * additional configuration steps. For all other changes we are done.
          */
diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
index acd013353cc7..8ecf409476cd 100644
--- a/drivers/net/wireless/rt2x00/rt2x00queue.c
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
@@ -213,8 +213,19 @@ static void rt2x00queue_create_tx_descriptor_seq(struct rt2x00_dev *rt2x00dev,
 
         __set_bit(ENTRY_TXD_GENERATE_SEQ, &txdesc->flags);
 
-        if (!test_bit(REQUIRE_SW_SEQNO, &rt2x00dev->cap_flags))
-                return;
+        if (!test_bit(REQUIRE_SW_SEQNO, &rt2x00dev->cap_flags)) {
+                /*
+                 * rt2800 has a H/W (or F/W) bug, device incorrectly increase
+                 * seqno on retransmited data (non-QOS) frames. To workaround
+                 * the problem let's generate seqno in software if QOS is
+                 * disabled.
+                 */
+                if (test_bit(CONFIG_QOS_DISABLED, &rt2x00dev->flags))
+                        __clear_bit(ENTRY_TXD_GENERATE_SEQ, &txdesc->flags);
+                else
+                        /* H/W will generate sequence number */
+                        return;
+        }
 
         /*
          * The hardware is not able to insert a sequence number. Assign a