iwlwifi: mvm: enable RX chain diversity if needed

In some situations (see comment) it makes sense to enable both
chains (if available) to get better throughput by having chain
diversity available.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
This commit is contained in:
Johannes Berg 2014-05-12 11:14:51 +02:00 committed by Emmanuel Grumbach
parent d6aeb354f9
commit 1a095d30d1

View File

@ -156,6 +156,19 @@ static void iwl_mvm_phy_ctxt_cmd_data(struct iwl_mvm *mvm,
idle_cnt = chains_static;
active_cnt = chains_dynamic;
/* In scenarios where we only ever use a single-stream rates,
* i.e. legacy 11b/g/a associations, single-stream APs or even
* static SMPS, enable both chains to get diversity, improving
* the case where we're far enough from the AP that attenuation
* between the two antennas is sufficiently different to impact
* performance.
*/
if (active_cnt == 1 && num_of_ant(mvm->fw->valid_rx_ant) > 1 &&
!mvm->cfg->rx_with_siso_diversity) {
idle_cnt = 2;
active_cnt = 2;
}
cmd->rxchain_info = cpu_to_le32(mvm->fw->valid_rx_ant <<
PHY_RX_CHAIN_VALID_POS);
cmd->rxchain_info |= cpu_to_le32(idle_cnt << PHY_RX_CHAIN_CNT_POS);