drm/i915: gen3 page flipping fixes

Gen3 chips have slightly different flip commands, and also contain a bit
that indicates whether a "flip pending" interrupt means the flip has
been queued or has been completed.

So implement support for the gen3 flip command, and make sure we use the
flip pending interrupt correctly depending on the value of ECOSKPD bit
0.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 84ce95602f00..4d59710c717e 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1408,6 +1408,10 @@ static int i915_load_modeset_init(struct drm_device *dev,
         if (ret)
                 goto destroy_ringbuffer;
 
+        /* IIR "flip pending" bit means done if this bit is set */
+        if (IS_GEN3(dev) && (I915_READ(ECOSKPD) & ECO_FLIP_DONE))
+                dev_priv->flip_pending_is_done = true;
+
         intel_modeset_init(dev);
 
         ret = drm_irq_install(dev);