diff options
authorJohannes Berg <johannes.berg@intel.com>2010-04-01 11:24:23 -0700
committerReinette Chatre <reinette.chatre@intel.com>2010-04-09 11:22:29 -0700
commit8b9fce77737ae9983f61ec56cd53f52fb738b2c7 (patch)
parentece6444c2fe80dab679beb5f0d58b091f1933b00 (diff)
iwlwifi: work around bogus active chains detection
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 <johannes.berg@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
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 845831ac053..64de42be7ea 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