drm/i915: add POSTING_READs to the IRQ init/reset macros

I previously chose to keep the POSTING_READ calls as something to be
done by the macro callers, but the conclusion after discussing this on
the mailing list is that leaving the POSTING_READ calls to the macros
makes the code safer, and the additional useless register reads
shouldn't be noticeable. So move the POSTING_READ calls to the
callers.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

1 files changed, 5 insertions, 11 deletions

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index b354c90ee8fe..bf7de4a37700 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -80,11 +80,7 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 	[HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
 };
 
-/*
- * IIR can theoretically queue up two events. Be paranoid.
- * Also, make sure callers of these macros have something equivalent to a
- * POSTING_READ on the IIR register.
- * */
+/* IIR can theoretically queue up two events. Be paranoid. */
 #define GEN8_IRQ_RESET_NDX(type, which) do { \
 	I915_WRITE(GEN8_##type##_IMR(which), 0xffffffff); \
 	POSTING_READ(GEN8_##type##_IMR(which)); \
@@ -92,6 +88,7 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 	I915_WRITE(GEN8_##type##_IIR(which), 0xffffffff); \
 	POSTING_READ(GEN8_##type##_IIR(which)); \
 	I915_WRITE(GEN8_##type##_IIR(which), 0xffffffff); \
+	POSTING_READ(GEN8_##type##_IIR(which)); \
 } while (0)
 
 #define GEN5_IRQ_RESET(type) do { \
@@ -101,6 +98,7 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 	I915_WRITE(type##IIR, 0xffffffff); \
 	POSTING_READ(type##IIR); \
 	I915_WRITE(type##IIR, 0xffffffff); \
+	POSTING_READ(type##IIR); \
 } while (0)
 
 /*
@@ -117,12 +115,14 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 	GEN5_ASSERT_IIR_IS_ZERO(GEN8_##type##_IIR(which)); \
 	I915_WRITE(GEN8_##type##_IMR(which), (imr_val)); \
 	I915_WRITE(GEN8_##type##_IER(which), (ier_val)); \
+	POSTING_READ(GEN8_##type##_IER(which)); \
 } while (0)
 
 #define GEN5_IRQ_INIT(type, imr_val, ier_val) do { \
 	GEN5_ASSERT_IIR_IS_ZERO(type##IIR); \
 	I915_WRITE(type##IMR, (imr_val)); \
 	I915_WRITE(type##IER, (ier_val)); \
+	POSTING_READ(type##IER); \
 } while (0)
 
 /* For display hotplug interrupt */
@@ -2897,7 +2897,6 @@ static void gen5_gt_irq_reset(struct drm_device *dev)
 	GEN5_IRQ_RESET(GT);
 	if (INTEL_INFO(dev)->gen >= 6)
 		GEN5_IRQ_RESET(GEN6_PM);
-	POSTING_READ(GTIIR);
 }
 
 /* drm_dma.h hooks
@@ -2971,7 +2970,6 @@ static void gen8_irq_reset(struct drm_device *dev)
 	GEN5_IRQ_RESET(GEN8_DE_PORT_);
 	GEN5_IRQ_RESET(GEN8_DE_MISC_);
 	GEN5_IRQ_RESET(GEN8_PCU_);
-	POSTING_READ(GEN8_PCU_IIR);
 
 	ibx_irq_reset(dev);
 }
@@ -3070,7 +3068,6 @@ static void gen5_gt_irq_postinstall(struct drm_device *dev)
 		dev_priv->pm_irq_mask = 0xffffffff;
 		GEN5_IRQ_INIT(GEN6_PM, dev_priv->pm_irq_mask, pm_irqs);
 	}
-	POSTING_READ(GTIER);
 }
 
 static int ironlake_irq_postinstall(struct drm_device *dev)
@@ -3198,7 +3195,6 @@ static void gen8_gt_irq_postinstall(struct drm_i915_private *dev_priv)
 
 	for (i = 0; i < ARRAY_SIZE(gt_interrupts); i++)
 		GEN8_IRQ_INIT_NDX(GT, i, ~gt_interrupts[i], gt_interrupts[i]);
-	POSTING_READ(GEN8_GT_IER(0));
 }
 
 static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
@@ -3217,10 +3213,8 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
 	for_each_pipe(pipe)
 		GEN8_IRQ_INIT_NDX(DE_PIPE, pipe, dev_priv->de_irq_mask[pipe],
 				  de_pipe_enables);
-	POSTING_READ(GEN8_DE_PIPE_ISR(0));
 
 	GEN5_IRQ_INIT(GEN8_DE_PORT_, ~GEN8_AUX_CHANNEL_A, GEN8_AUX_CHANNEL_A);
-	POSTING_READ(GEN8_DE_PORT_IER);
 }
 
 static int gen8_irq_postinstall(struct drm_device *dev)