| From | Greg Kroah-Hartman <> | Subject | [ 061/187] ath9k: Fix softlockup in AR9485 | Date | Thu, 12 Jul 2012 15:33:37 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
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From: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
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>
--- 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 @@ -960,6 +960,15 @@ 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);
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