svn commit: r265029 - head/sys/dev/ath/ath_hal/ar5416

[Adrian Chadd]

Author: adrian
Date: Sun Apr 27 23:31:42 2014
New Revision: 265029
URL: http://svnweb.freebsd.org/changeset/base/265029

Log:
  Do a read-after-write to ensure the interrupt register update is flushed
  to the hardware.
  
  The QCA HAL has a comment noting that if this isn't done, modifications
  to AR_IMR_S2 before AR_IMR is flushed may produce spurious interrupts.
  
  Obtained from:	QCA

Modified:
  head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c

Modified: head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c
==============================================================================
--- head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c	Sun Apr 27 22:18:33 2014	(r265028)
+++ head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c	Sun Apr 27 23:31:42 2014	(r265029)
@@ -337,6 +337,9 @@ ar5416SetInterrupts(struct ath_hal *ah, 
 	/* Write the new IMR and store off our SW copy. */
 	HALDEBUG(ah, HAL_DEBUG_INTERRUPT, "%s: new IMR 0x%x\n", __func__, mask);
 	OS_REG_WRITE(ah, AR_IMR, mask);
+	/* Flush write */
+	(void) OS_REG_READ(ah, AR_IMR);
+
 	mask = OS_REG_READ(ah, AR_IMR_S2) & ~(AR_IMR_S2_TIM |
 					AR_IMR_S2_DTIM |
 					AR_IMR_S2_DTIMSYNC |