iwl3945: do not send scan command if channel count zero

Do not send scan command if no channels to scan.

This avoids a Microcode error as reported in:
http://www.intellinuxwireless.org/bugzilla/show_bug.cgi?id=1650
http://bugzilla.kernel.org/show_bug.cgi?id=11806
http://marc.info/?l=linux-wireless&m=122437145211886&w=2

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index b9eac5551d8..81dfcb88285 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -6256,6 +6256,11 @@ static void iwl3945_bg_request_scan(struct work_struct *data)
                                               n_probes,
                         (void *)&scan->data[le16_to_cpu(scan->tx_cmd.len)]);
 
+        if (scan->channel_count == 0) {
+                IWL_DEBUG_SCAN("channel count %d\n", scan->channel_count);
+                goto done;
+        }
+
         cmd.len += le16_to_cpu(scan->tx_cmd.len) +
             scan->channel_count * sizeof(struct iwl3945_scan_channel);
         cmd.data = scan;