Disable master interrupt before reading level indications.
This will close a race where we get a level indication between
reading and disabling, generating an extra interrupt where we
could have avoided one.
Further, as the reading acts also as a post, replace the
write/post on the irq reset with the helper. On enabling side,
posting doesn't serve any purpose so it can also be replaced
with helper.
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuopp...@linux.intel.com>
---
drivers/gpu/drm/i915/i915_irq.c | 36 ++++++++++++++++++++++++---------
1 file changed, 26 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2e242270e270..cbc04dd59041 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2887,21 +2887,39 @@ gen8_de_irq_handler(struct drm_i915_private *dev_priv,
u32 master_ctl)
return ret;
}
+static inline u32 gen8_master_intr_disable(void __iomem * const regs)
+{
+ raw_reg_write(regs, GEN8_MASTER_IRQ, 0);
+
+ /*
+ * Now with master disabled, get a sample of level indications
+ * for this interrupt. Indications will be cleared on related acks.
+ * New indications can and will light up during processing,
+ * and will generate new interrupt after enabling master.
+ */
+ return raw_reg_read(regs, GEN8_MASTER_IRQ);
+}
+
+static inline void gen8_master_intr_enable(void __iomem * const regs)
+{
+ raw_reg_write(regs, GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
+}
+
static irqreturn_t gen8_irq_handler(int irq, void *arg)
{
struct drm_i915_private *dev_priv = to_i915(arg);
+ void __iomem * const regs = dev_priv->regs;
u32 master_ctl;
u32 gt_iir[4];
if (!intel_irqs_enabled(dev_priv))
return IRQ_NONE;
- master_ctl = I915_READ_FW(GEN8_MASTER_IRQ);
- master_ctl &= ~GEN8_MASTER_IRQ_CONTROL;
- if (!master_ctl)
+ master_ctl = gen8_master_intr_disable(regs);
+ if (!master_ctl) {
+ gen8_master_intr_enable(regs);
return IRQ_NONE;
-
- I915_WRITE_FW(GEN8_MASTER_IRQ, 0);
+ }
/* Find, clear, then process each source of interrupt */
gen8_gt_irq_ack(dev_priv, master_ctl, gt_iir);
@@ -2913,7 +2931,7 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
enable_rpm_wakeref_asserts(dev_priv);
}
- I915_WRITE_FW(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
+ gen8_master_intr_enable(regs);
gen8_gt_irq_handler(dev_priv, master_ctl, gt_iir);
@@ -3598,8 +3616,7 @@ static void gen8_irq_reset(struct drm_device *dev)
struct drm_i915_private *dev_priv = to_i915(dev);
int pipe;
- I915_WRITE(GEN8_MASTER_IRQ, 0);
- POSTING_READ(GEN8_MASTER_IRQ);
+ gen8_master_intr_disable(dev_priv->regs);
gen8_gt_irq_reset(dev_priv);
@@ -4244,8 +4261,7 @@ static int gen8_irq_postinstall(struct drm_device *dev)
if (HAS_PCH_SPLIT(dev_priv))
ibx_irq_postinstall(dev);
- I915_WRITE(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
- POSTING_READ(GEN8_MASTER_IRQ);
+ gen8_master_intr_enable(dev_priv->regs);
return 0;
}
--
2.17.1
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