From: Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx> Please note this is the backported version for the linux stable tree, while the patch for wireless-testing tree http://permalink.gmane.org/gmane.linux.kernel.wireless.general/92608 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@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx [3.0+] Tested-by: Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx> Signed-off-by: Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx> --- drivers/net/wireless/ath/ath9k/main.c | 9 +++++++++ 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 4de4473..41096f6 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -971,6 +971,15 @@ 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); -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
