[intel] Get vblank pipe from irq_mask_reg instead of hardware enable reg

With the interrupt enable/disable using only the mask register, it was wrong
to use the enable register to detect which pipes had vblank detection
turned on. Also, as we keep a local copy of the mask register around, and
MSI machines smack the hardware during the interrupt handler, it is more
efficient and more correct to use the local copy.

1 files changed, 3 insertions, 2 deletions

diff --git a/shared-core/i915_irq.c b/shared-core/i915_irq.c
index 710b2896..f09ae5f7 100644
--- a/shared-core/i915_irq.c
+++ b/shared-core/i915_irq.c
@@ -794,14 +794,15 @@ int i915_vblank_pipe_get(struct drm_device *dev, void *data,
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	drm_i915_vblank_pipe_t *pipe = data;
-	u16 flag;
+	u32 flag = 0;
 
 	if (!dev_priv) {
 		DRM_ERROR("called with no initialization\n");
 		return -EINVAL;
 	}
 
-	flag = I915_READ(I915REG_INT_ENABLE_R);
+	if (dev_priv->irq_enabled)
+	    flag = ~dev_priv->irq_mask_reg;
 	pipe->pipe = 0;
 	if (flag & I915_DISPLAY_PIPE_A_EVENT_INTERRUPT)
 		pipe->pipe |= DRM_I915_VBLANK_PIPE_A;