wl1271: Work around AP's with broken ps-poll functionality

Some AP's (such as Zyxel Prestige 600) have totally broken ps-poll
functionality. When powersave is enabled, these AP's will set the TIM bit for
a STA in beacons, but when the STA responds with a ps-poll, the AP does not
respond with data.

The wl1271 firmware is able to send an indication to the host, when this
problem occurs. This patch adds implementation, which temporarily disables
power-save in response to this indication, allowing the AP to transmit whatever
data it has buffered for the STA / whatever data is inbound at that time.

This patch does not make these AP's work reliably in PSM, but improves the
chances of inbound data getting through.

The side effect of this patch is increased power consumption when using a
faulty AP.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/drivers/net/wireless/wl12xx/wl1271_event.c b/drivers/net/wireless/wl12xx/wl1271_event.c
index ca52cdec7a8f..15f6b86f81a2 100644
--- a/drivers/net/wireless/wl12xx/wl1271_event.c
+++ b/drivers/net/wireless/wl12xx/wl1271_event.c
@@ -28,6 +28,63 @@
 #include "wl1271_ps.h"
 #include "wl12xx_80211.h"
 
+void wl1271_pspoll_work(struct work_struct *work)
+{
+        struct delayed_work *dwork;
+        struct wl1271 *wl;
+
+        dwork = container_of(work, struct delayed_work, work);
+        wl = container_of(dwork, struct wl1271, pspoll_work);
+
+        wl1271_debug(DEBUG_EVENT, "pspoll work");
+
+        mutex_lock(&wl->mutex);
+
+        if (!test_and_clear_bit(WL1271_FLAG_PSPOLL_FAILURE, &wl->flags))
+                goto out;
+
+        if (!test_bit(WL1271_FLAG_STA_ASSOCIATED, &wl->flags))
+                goto out;
+
+        /*
+         * if we end up here, then we were in powersave when the pspoll
+         * delivery failure occurred, and no-one changed state since, so
+         * we should go back to powersave.
+         */
+        wl1271_ps_set_mode(wl, STATION_POWER_SAVE_MODE, true);
+
+out:
+        mutex_unlock(&wl->mutex);
+};
+
+static void wl1271_event_pspoll_delivery_fail(struct wl1271 *wl)
+{
+        int delay = wl->conf.conn.ps_poll_recovery_period;
+        int ret;
+
+        wl->ps_poll_failures++;
+        if (wl->ps_poll_failures == 1)
+                wl1271_info("AP with dysfunctional ps-poll, "
+                            "trying to work around it.");
+
+        /* force active mode receive data from the AP */
+        if (test_bit(WL1271_FLAG_PSM, &wl->flags)) {
+                ret = wl1271_ps_set_mode(wl, STATION_ACTIVE_MODE, true);
+                if (ret < 0)
+                        return;
+                set_bit(WL1271_FLAG_PSPOLL_FAILURE, &wl->flags);
+                ieee80211_queue_delayed_work(wl->hw, &wl->pspoll_work,
+                                             msecs_to_jiffies(delay));
+        }
+
+        /*
+         * If already in active mode, lets we should be getting data from
+         * the AP right away. If we enter PSM too fast after this, and data
+         * remains on the AP, we will get another event like this, and we'll
+         * go into active once more.
+         */
+}
+
 static int wl1271_event_scan_complete(struct wl1271 *wl,
                                       struct event_mailbox *mbox)
 {
@@ -191,6 +248,9 @@ static int wl1271_event_process(struct wl1271 *wl, struct event_mailbox *mbox)
                         return ret;
         }
 
+        if (vector & PSPOLL_DELIVERY_FAILURE_EVENT_ID)
+                wl1271_event_pspoll_delivery_fail(wl);
+
         if (vector & RSSI_SNR_TRIGGER_0_EVENT_ID) {
                 wl1271_debug(DEBUG_EVENT, "RSSI_SNR_TRIGGER_0_EVENT");
                 if (wl->vif)