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authorMohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>2012-06-13 21:28:09 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-16 08:47:38 -0700
commitde39eed0da6d7afcf2d758dc0e99811988a3bd06 (patch)
treef58f8fae668f1db3750944713d0854201b96e321
parentb1c5701ad6b3e5d21d16f65475651cfaaa41e7aa (diff)
ath9k: Fix softlockup in AR9485
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: [<ffffffffa0517490>] ? ath_hw_check+0xe0/0xe0 [ath9k] [<ffffffff812cd1e8>] __const_udelay+0x28/0x30 [<ffffffffa03bae7a>] ar9003_get_pll_sqsum_dvc+0x4a/0x80 [ath9k_hw] [<ffffffffa05174eb>] ath_hw_pll_work+0x5b/0xe0 [ath9k] [<ffffffff810744fe>] process_one_work+0x11e/0x470 [<ffffffff8107530f>] worker_thread+0x15f/0x360 [<ffffffff810751b0>] ? manage_workers+0x230/0x230 [<ffffffff81079af3>] kthread+0x93/0xa0 [<ffffffff815fd3a4>] kernel_thread_helper+0x4/0x10 [<ffffffff81079a60>] ? kthread_freezable_should_stop+0x70/0x70 [<ffffffff815fd3a0>] ? 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 <rolf.offermanns@gmx.net> Tested-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com> Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/wireless/ath/ath9k/main.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index a126a3e238f6..633f96203e2f 100644
--- 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 *work)
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);