ath9k: never read from the AR_IMR_S2 register

The AR_IMR_S2 register sometimes cannot be read correctly.  Instead of a
valid value, 0xdeadbeef is returned.  The driver has been observed
writing that value back to AR_IMR_S2 after changing a few bits.

Cache the register value in ah->imrs2_reg and always write chached value
to the register.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index dbbf7ca5f97d..20d90268ce31 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -479,6 +479,7 @@ struct ath_hw {
 
         int16_t curchan_rad_index;
         u32 mask_reg;
+        u32 imrs2_reg;
         u32 txok_interrupt_mask;
         u32 txerr_interrupt_mask;
         u32 txdesc_interrupt_mask;