drm/i915: Opt out of vblank disable timer on >gen2

Now that the vblank races are plugged, we can opt out of using
the vblank disable timer and just let vblank interrupts get
disabled immediately when the last reference is dropped.

Gen2 is the exception since it has no hardware frame counter.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6ef9d6fabf80431a60747a1db9598167e48d7905..845f0f6c1eeb57c62c377c5e86826c180d2ab1ea 100644 (file)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -4680,6 +4680,14 @@ void intel_irq_init(struct drm_device *dev)
                dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */
        }
 
+       /*
+        * Opt out of the vblank disable timer on everything except gen2.
+        * Gen2 doesn't have a hardware frame counter and so depends on
+        * vblank interrupts to produce sane vblank seuquence numbers.
+        */
+       if (!IS_GEN2(dev))
+               dev->vblank_disable_immediate = true;
+
        if (drm_core_check_feature(dev, DRIVER_MODESET)) {
                dev->driver->get_vblank_timestamp = i915_get_vblank_timestamp;
                dev->driver->get_scanout_position = i915_get_crtc_scanoutpos;