hi!
i sent this for review here, before i bother the people at linux-wireless with
it, also since my patches usually seem to need two or three rounds of minor
fix ups ;)
this addresses the issue mentioned on the madwifi lists for ath5k.
bruno
On Tuesday 11 December 2007 17:07:41 Bruno Randolf wrote:
> setting up tx descriptors with a rate of zero will put the HW into a mode
> where it continously sends noise on the channel, thus blocking the whole
> channel. since it is important to avoid this situation, add a WARN_ON in
> these cases, even if we hope to never get bad rates from the rate control
> module.
>
> Changes-licensed-under: ISC
> Signed-off-by: Bruno Randolf <[EMAIL PROTECTED]>
> ---
> drivers/net/wireless/ath5k/hw.c | 40
> +++++++++++++++++++++++++++++++++++++- 1 files changed, 38 insertions(+), 2
> deletions(-)
>
> diff --git a/drivers/net/wireless/ath5k/hw.c
> b/drivers/net/wireless/ath5k/hw.c index 83fd241..6181066 100644
> --- a/drivers/net/wireless/ath5k/hw.c
> +++ b/drivers/net/wireless/ath5k/hw.c
> @@ -3476,9 +3476,20 @@ ath5k_hw_setup_2word_tx_desc(struct ath5k_hw *ah,
> struct ath5k_desc *desc,
>
> /*
> * Validate input
> + * - Zero retries don't make sense.
> + * - A zero rate will put the HW into a mode where it continously sends
> + * noise on the channel, so it is important to avoid this.
> */
> - if (tx_tries0 == 0)
> + if (unlikely(tx_tries0 == 0)) {
> + ATH5K_ERR(ah->ah_sc, "zero retries\n");
> + WARN_ON(1);
> return -EINVAL;
> + }
> + if (unlikely(tx_rate0 == 0)) {
> + ATH5K_ERR(ah->ah_sc, "zero rate\n");
> + WARN_ON(1);
> + return -EINVAL;
> + }
>
> /* Clear status descriptor */
> memset(desc->ds_hw, 0, sizeof(struct ath5k_hw_tx_status));
> @@ -3595,9 +3606,20 @@ static int ath5k_hw_setup_4word_tx_desc(struct
> ath5k_hw *ah,
>
> /*
> * Validate input
> + * - Zero retries don't make sense.
> + * - A zero rate will put the HW into a mode where it continously sends
> + * noise on the channel, so it is important to avoid this.
> */
> - if (tx_tries0 == 0)
> + if (unlikely(tx_tries0 == 0)) {
> + ATH5K_ERR(ah->ah_sc, "zero retries\n");
> + WARN_ON(1);
> return -EINVAL;
> + }
> + if (unlikely(tx_rate0 == 0)) {
> + ATH5K_ERR(ah->ah_sc, "zero rate\n");
> + WARN_ON(1);
> + return -EINVAL;
> + }
>
> /* Clear status descriptor */
> memset(tx_status, 0, sizeof(struct ath5k_hw_tx_status));
> @@ -3686,6 +3708,20 @@ ath5k_hw_setup_xr_tx_desc(struct ath5k_hw *ah,
> struct ath5k_desc *desc, {
> struct ath5k_hw_4w_tx_desc *tx_desc;
>
> + /*
> + * Rates can be 0 as long as the retry count is 0 too.
> + * A zero rate and nonzero retry count will put the HW into a mode where
> + * it continously sends noise on the channel, so it is important to
> + * avoid this.
> + */
> + if (unlikely((tx_rate1 == 0 && tx_tries1 != 0) ||
> + (tx_rate2 == 0 && tx_tries2 != 0) ||
> + (tx_rate3 == 0 && tx_tries3 != 0))) {
> + ATH5K_ERR(ah->ah_sc, "zero rate\n");
> + WARN_ON(1);
> + return -EINVAL;
> + }
> +
> if (ah->ah_version == AR5K_AR5212) {
> tx_desc = (struct ath5k_hw_4w_tx_desc *)&desc->ds_ctl0;
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