Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...

[safe/jmp/linux-2.6] / drivers / net / wireless / ath9k / hw.c

diff --git a/drivers/net/wireless/ath9k/hw.c b/drivers/net/wireless/ath9k/hw.c
index ea550cc..d494e98 100644 (file)
--- a/drivers/net/wireless/ath9k/hw.c
+++ b/drivers/net/wireless/ath9k/hw.c
@@ -391,6 +391,25 @@ static void ath9k_hw_set_defaults(struct ath_hw *ah)
        }
 
        ah->config.intr_mitigation = 1;
+
+       /*
+        * We need this for PCI devices only (Cardbus, PCI, miniPCI)
+        * _and_ if on non-uniprocessor systems (Multiprocessor/HT).
+        * This means we use it for all AR5416 devices, and the few
+        * minor PCI AR9280 devices out there.
+        *
+        * Serialization is required because these devices do not handle
+        * well the case of two concurrent reads/writes due to the latency
+        * involved. During one read/write another read/write can be issued
+        * on another CPU while the previous read/write may still be working
+        * on our hardware, if we hit this case the hardware poops in a loop.
+        * We prevent this by serializing reads and writes.
+        *
+        * This issue is not present on PCI-Express devices or pre-AR5416
+        * devices (legacy, 802.11abg).
+        */
+       if (num_possible_cpus() > 1)
+               ah->config.serialize_regmode = SER_REG_MODE_AUTO;
 }
 
 static struct ath_hw *ath9k_hw_newstate(u16 devid, struct ath_softc *sc,
@@ -610,7 +629,8 @@ static struct ath_hw *ath9k_hw_do_attach(u16 devid, struct ath_softc *sc,
        }
 
        if (ah->config.serialize_regmode == SER_REG_MODE_AUTO) {
-               if (ah->hw_version.macVersion == AR_SREV_VERSION_5416_PCI) {
+               if (ah->hw_version.macVersion == AR_SREV_VERSION_5416_PCI ||
+                   (AR_SREV_9280(ah) && !ah->is_pciexpress)) {
                        ah->config.serialize_regmode =
                                SER_REG_MODE_ON;
                } else {