iwlwifi: disable powersave for 4965

There's a bug in 4965 powersave that appears to
be related to the way it keeps track of its data
during sleep, but we haven't found it yet. Due to
that, using powersave may spontaneously cause the
device to SYSASSERT when transitioning from sleep
to wake. Therefore, disable powersave for 4965,
until (if ever, unfortunately) we can identify
and fix the problem.

Cf. http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=1982
which was closed, but now has re-appeared with
IDLE mode, which probably means we never really
fixed it.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-4965.c

@@ -2346,6 +2346,7 @@ struct iwl_cfg iwl4965_agn_cfg = {
 	.mod_params = &iwl4965_mod_params,
 	.use_isr_legacy = true,
 	.ht_greenfield_support = false,
+	.broken_powersave = true,
 };
 
 /* Module firmware */

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -1585,9 +1585,12 @@ int iwl_setup_mac(struct iwl_priv *priv)
 	hw->flags = IEEE80211_HW_SIGNAL_DBM |
 		    IEEE80211_HW_NOISE_DBM |
 		    IEEE80211_HW_AMPDU_AGGREGATION |
-		    IEEE80211_HW_SPECTRUM_MGMT |
-		    IEEE80211_HW_SUPPORTS_PS |
+		    IEEE80211_HW_SPECTRUM_MGMT;
+
+	if (!priv->cfg->broken_powersave)
+		hw->flags |= IEEE80211_HW_SUPPORTS_PS |
 			     IEEE80211_HW_SUPPORTS_DYNAMIC_PS;
+
 	hw->wiphy->interface_modes =
 		BIT(NL80211_IFTYPE_STATION) |
 		BIT(NL80211_IFTYPE_ADHOC);

drivers/net/wireless/iwlwifi/iwl-core.h

@@ -252,6 +252,7 @@ struct iwl_cfg {
 	const u16 max_ll_items;
 	const bool shadow_ram_support;
 	const bool ht_greenfield_support;
+	const bool broken_powersave;
 };
 
 /***************************

drivers/net/wireless/iwlwifi/iwl-power.c

@@ -292,8 +292,9 @@ int iwl_power_update_mode(struct iwl_priv *priv, bool force)
 	else
 		dtimper = 1;
 
-	/* TT power setting overwrites everything */
-	if (tt->state >= IWL_TI_1)
+	if (priv->cfg->broken_powersave)
+		iwl_power_sleep_cam_cmd(priv, &cmd);
+	else if (tt->state >= IWL_TI_1)
 		iwl_static_sleep_cmd(priv, &cmd, tt->tt_power_mode, dtimper);
 	else if (!enabled)
 		iwl_power_sleep_cam_cmd(priv, &cmd);