Patch "mac80211: fix power saving clients handling in iwlwifi" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

mac80211: fix power saving clients handling in iwlwifi

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mac80211-fix-power-saving-clients-handling-in-iwlwifi.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Emmanuel Grumbach <[email protected]>
Date: Mon, 20 Feb 2017 14:24:36 +0100
Subject: mac80211: fix power saving clients handling in iwlwifi

From: Emmanuel Grumbach <[email protected]>

[ Upstream commit d98937f4ea713d21e0fcc345919f86c877dd8d6f ]

iwlwifi now supports RSS and can't let mac80211 track the PS state based on the Rx frames since they can come out of order. iwlwifi is now advertising AP_LINK_PS, and uses explicit notifications to teach mac80211 about the PS state of the stations and the PS poll / uAPSD trigger frames coming our way from the peers.

Because of that, the TIM stopped being maintained in
mac80211. I tried to fix this in commit c68df2e7be0c ("mac80211: allow using AP_LINK_PS with mac80211-generated TIM IE") but that was later reverted by Felix in commit 6c18a6b4e799 ("Revert "mac80211: allow using AP_LINK_PS with mac80211-generated TIM IE") since it broke drivers that do not implement set_tim.

Since none of the drivers that set AP_LINK_PS have the set_tim() handler set besides iwlwifi, I can bail out in __sta_info_recalc_tim if AP_LINK_PS AND .set_tim is not implemented.

---
 net/mac80211/sta_info.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -688,7 +688,7 @@ static void __sta_info_recalc_tim(struct
 	}
 
 	/* No need to do anything if the driver does all */
-	if (ieee80211_hw_check(&local->hw, AP_LINK_PS))
+	if (ieee80211_hw_check(&local->hw, AP_LINK_PS) && !local->ops->set_tim)
 		return;
 
 	if (sta->dead)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mac80211-fix-power-saving-clients-handling-in-iwlwifi.patch