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iwlwifi: set TX_CMD_FLAG_PROT_REQUIRE_MSK in tx_flag
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When building tx command, always set TX_CMD_FLAG_PROT_REQUIRE_MSK
for 5000 series and up.

Without setting this bit the firmware will not examine the RTS/CTS setting
and thus not send traffic with the appropriate protection. RTS/CTS is is
required for HT traffic in a noisy environment where, without this setting,
connections will stall on some hardware as documented in the patch that
initially attempted to address this:

    commit 1152dcc
    Author: Wey-Yi Guy <wey-yi.w.guy@intel.com>
    Date:   Fri Jan 15 13:42:58 2010 -0800

    iwlwifi: Fix throughput stall issue in HT mode for 5000

    Similar to 6000 and 1000 series, RTS/CTS is the recommended
    protection mechanism for 5000 series in HT mode based on the HW design.
    Using RTS/CTS will better protect the inner exchange from interference,
    especially in highly-congested environment, it also prevent uCode encounter
    TX FIFO underrun and other HT mode related performance issues.

For 3945 and 4965, different flags are used for RTS/CTS or CTS-to-Self
protection.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
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Wey-Yi Guy authored and Reinette Chatre committed Jun 25, 2010
1 parent d1e89f3 commit 062bee4
Showing 1 changed file with 1 addition and 5 deletions.
6 changes: 1 addition & 5 deletions drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
Original file line number Diff line number Diff line change
Expand Up @@ -212,11 +212,7 @@ static void iwlagn_chain_noise_reset(struct iwl_priv *priv)
static void iwlagn_rts_tx_cmd_flag(struct ieee80211_tx_info *info,
__le32 *tx_flags)
{
if ((info->control.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
(info->control.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
*tx_flags |= TX_CMD_FLG_RTS_CTS_MSK;
else
*tx_flags &= ~TX_CMD_FLG_RTS_CTS_MSK;
*tx_flags |= TX_CMD_FLG_RTS_CTS_MSK;
}

/* Calc max signal level (dBm) among 3 possible receivers */
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