[rt2x00-users] [PATCH 2/2] rt2x00: do not generate seqno in h/w if QOS is disabled

[Helmut Schaa]

On Mon, Apr 2, 2012 at 1:21 PM, Stanislaw Gruszka <sgruszka at redhat.com> wrote:
> 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 at yahoo.com>
> Signed-off-by: Stanislaw Gruszka <sgruszka at redhat.com>

I don't have a better idea right now :) so this workaround looks suitable to me.

Acked-by: Helmut Schaa <helmut.schaa at googlemail.com>

Thanks for tracking this down Stanislaw!

> ---
>  drivers/net/wireless/rt2x00/rt2x00.h      |    1 +
>  drivers/net/wireless/rt2x00/rt2x00mac.c   |   10 ++++++++++
>  drivers/net/wireless/rt2x00/rt2x00queue.c |   15 +++++++++++++--
>  3 files changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
> index 8de9bfc..5583214 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 2df2eb6..b49773e 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 f7403cf..5019a3e 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
> --
> 1.7.1
>
> --
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