On 1/22/2019 6:32 PM, Daniele Ceraolo Spurio wrote:
When reading GEN11_GT_INTR_DWx closely after enabling the interrupts
in gen11_irq_postinstall, the returned value is garbage. This can
To clarify, this only happens (or at least I've only seen it) during
runtime_resume.
Daniele
cause other parts of the setup code (e.g. gen11_reset_one_iir) to
think that there are interrupts to be cleared when there are none.
The garbage value is only seen on the first read done after the enable,
so this looks like a posting issue. Adding a posting read after enabling
the interrupts does indeed fix the problem.
Note that the posting read has been purposely added outside of
gen11_master_intr_enable since the issue has only been observed when the
full interrupt setup is performed.
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_irq.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 5fd5080c4ccb..7056ae2d1e0e 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -4089,6 +4089,7 @@ static int gen11_irq_postinstall(struct drm_device *dev)
I915_WRITE(GEN11_DISPLAY_INT_CTL, GEN11_DISPLAY_IRQ_ENABLE);
gen11_master_intr_enable(dev_priv->regs);
+ POSTING_READ(GEN11_GFX_MSTR_IRQ);
return 0;
}
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
