From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162603Ab2GLXD5 (ORCPT ); Thu, 12 Jul 2012 19:03:57 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:63192 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162583Ab2GLXDx (ORCPT ); Thu, 12 Jul 2012 19:03:53 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Rolf Offermanns , Mohammed Shafi Shajakhan , "John W. Linville" Subject: [ 21/68] ath9k: Fix softlockup in AR9485 Date: Thu, 12 Jul 2012 16:01:55 -0700 Message-Id: <20120712175037.323234452@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712175035.530652872@linuxfoundation.org> References: <20120712175057.GA9917@kroah.com> <20120712175035.530652872@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mohammed Shafi Shajakhan commit bcb7ad7bcbef030e6ba71ede1f9866368aca7c99 upstream. steps to recreate: load latest ath9k driver with AR9485 stop the network-manager and wpa_supplicant bring the interface up Call Trace: [] ? ath_hw_check+0xe0/0xe0 [ath9k] [] __const_udelay+0x28/0x30 [] ar9003_get_pll_sqsum_dvc+0x4a/0x80 [ath9k_hw] [] ath_hw_pll_work+0x5b/0xe0 [ath9k] [] process_one_work+0x11e/0x470 [] worker_thread+0x15f/0x360 [] ? manage_workers+0x230/0x230 [] kthread+0x93/0xa0 [] kernel_thread_helper+0x4/0x10 [] ? kthread_freezable_should_stop+0x70/0x70 [] ? gs_change+0x13/0x13 ensure that the PLL-WAR for AR9485/AR9340 is executed only if the STA is associated (or) IBSS/AP mode had started beaconing. Ideally this WAR is needed to recover from some rare beacon stuck during stress testing. Before the STA is associated/IBSS had started beaconing, PLL4(0x1618c) always seem to have zero even though we had configured PLL3(0x16188) to query about PLL's locking status. When we keep on polling infinitely PLL4's 8th bit(ie check for PLL locking measurements is done), machine hangs due to softlockup. fixes https://bugzilla.redhat.com/show_bug.cgi?id=811142 Reported-by: Rolf Offermanns Tested-by: Mohammed Shafi Shajakhan Signed-off-by: Mohammed Shafi Shajakhan Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/ath/ath9k/main.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -648,6 +648,15 @@ void ath_hw_pll_work(struct work_struct hw_pll_work.work); u32 pll_sqsum; + /* + * ensure that the PLL WAR is executed only + * after the STA is associated (or) if the + * beaconing had started in interfaces that + * uses beacons. + */ + if (!(sc->sc_flags & SC_OP_BEACONS)) + return; + if (AR_SREV_9485(sc->sc_ah)) { ath9k_ps_wakeup(sc);