From: Johannes Berg <[email protected]>
The current algorithm will sometimes "detect" that
more chains are enabled than are really present in
the device because, for unknown reasons, the ucode
sends up all-zeroes signal values.
The simplest way of solving this is to restrict the
active chains mask to the chains we know are really
present on the device.
This fixes a bug with some devices where, since sometimes
more chains are enabled than really present, the system would hang.
Signed-off-by: Johannes Berg <[email protected]>
Signed-off-by: Reinette Chatre <[email protected]>
---
This patch is also available from wireless-2.6 branch on
git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi-2.6.git
drivers/net/wireless/iwlwifi/iwl-calib.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/drivers/net/wireless/iwlwifi/iwl-calib.c b/drivers/net/wireless/iwlwifi/iwl-calib.c
index 845831a..64de42b 100644
--- a/drivers/net/wireless/iwlwifi/iwl-calib.c
+++ b/drivers/net/wireless/iwlwifi/iwl-calib.c
@@ -807,6 +807,18 @@ void iwl_chain_noise_calibration(struct iwl_priv *priv,
}
}
+ /*
+ * The above algorithm sometimes fails when the ucode
+ * reports 0 for all chains. It's not clear why that
+ * happens to start with, but it is then causing trouble
+ * because this can make us enable more chains than the
+ * hardware really has.
+ *
+ * To be safe, simply mask out any chains that we know
+ * are not on the device.
+ */
+ active_chains &= priv->hw_params.valid_rx_ant;
+
num_tx_chains = 0;
for (i = 0; i < NUM_RX_CHAINS; i++) {
/* loops on all the bits of
--
1.6.3.3