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>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
index acd013353cc..8ecf409476c 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