From 5882da02e9d9089b7e8c739f3e774aaeeff8b7ba Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Fri, 8 Apr 2011 20:13:18 +0200 Subject: ath9k_hw: fix stopping rx DMA during resets During PHY errors, the MAC can sometimes fail to enter an idle state on older hardware (before AR9380) after an rx stop has been requested. This typically shows up in the kernel log with messages like these: ath: Could not stop RX, we could be confusing the DMA engine when we start RX up ------------[ cut here ]------------ WARNING: at drivers/net/wireless/ath/ath9k/recv.c:504 ath_stoprecv+0xcc/0xf0 [ath9k]() Call Trace: [<8023f0e8>] dump_stack+0x8/0x34 [<80075050>] warn_slowpath_common+0x78/0xa4 [<80075094>] warn_slowpath_null+0x18/0x24 [<80d66d60>] ath_stoprecv+0xcc/0xf0 [ath9k] [<80d642cc>] ath_set_channel+0xbc/0x270 [ath9k] [<80d65254>] ath_radio_disable+0x4a4/0x7fc [ath9k] When this happens, the state that the MAC enters is easy to identify and does not result in bogus DMA traffic, however to ensure a working state after a channel change, the hardware should still be reset. This patch adds detection for this specific MAC state, after which the above warnings completely disappear in my tests. Signed-off-by: Felix Fietkau Cc: stable@kernel.org Cc: Kyungwan Nam Signed-off-by: John W. Linville --- drivers/net/wireless/ath/ath9k/recv.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/net/wireless/ath/ath9k/recv.c') diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c index a9c3f4672aa0..dcd19bc337d1 100644 --- a/drivers/net/wireless/ath/ath9k/recv.c +++ b/drivers/net/wireless/ath/ath9k/recv.c @@ -486,12 +486,12 @@ start_recv: bool ath_stoprecv(struct ath_softc *sc) { struct ath_hw *ah = sc->sc_ah; - bool stopped; + bool stopped, reset = false; spin_lock_bh(&sc->rx.rxbuflock); ath9k_hw_abortpcurecv(ah); ath9k_hw_setrxfilter(ah, 0); - stopped = ath9k_hw_stopdmarecv(ah); + stopped = ath9k_hw_stopdmarecv(ah, &reset); if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) ath_edma_stop_recv(sc); @@ -506,7 +506,7 @@ bool ath_stoprecv(struct ath_softc *sc) "confusing the DMA engine when we start RX up\n"); ATH_DBG_WARN_ON_ONCE(!stopped); } - return stopped; + return stopped || reset; } void ath_flushrecv(struct ath_softc *sc) -- cgit v1.2.3 From 2232d31bf18ba02f5cd632bbfc3466aeca394c75 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Fri, 15 Apr 2011 00:41:43 +0200 Subject: ath9k: fix the return value of ath_stoprecv The patch 'ath9k_hw: fix stopping rx DMA during resets' added code to detect a condition where rx DMA was stopped, but the MAC failed to enter the idle state. This condition requires a hardware reset, however the return value of ath_stoprecv was 'true' in that case, which allowed it to skip the reset when issuing a fast channel change. Signed-off-by: Felix Fietkau Reported-by: Paul Stewart Cc: stable@kernel.org Signed-off-by: John W. Linville --- drivers/net/wireless/ath/ath9k/recv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/wireless/ath/ath9k/recv.c') diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c index dcd19bc337d1..b29c80def35e 100644 --- a/drivers/net/wireless/ath/ath9k/recv.c +++ b/drivers/net/wireless/ath/ath9k/recv.c @@ -506,7 +506,7 @@ bool ath_stoprecv(struct ath_softc *sc) "confusing the DMA engine when we start RX up\n"); ATH_DBG_WARN_ON_ONCE(!stopped); } - return stopped || reset; + return stopped && !reset; } void ath_flushrecv(struct ath_softc *sc) -- cgit v1.2.3