drm: add support for secondary vertical blank interrupt to i915

When the vertical blank interrupt is enabled for both pipes, pipe A is
considered primary and pipe B secondary. When it's only enabled for one pipe,
it's always considered primary for backwards compatibility.

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/i915_drv.c b/drivers/char/drm/i915_drv.c
index 8e2e609..85bcc27 100644
--- a/drivers/char/drm/i915_drv.c
+++ b/drivers/char/drm/i915_drv.c
@@ -44,12 +44,14 @@
 	 */
 	.driver_features =
 	    DRIVER_USE_AGP | DRIVER_REQUIRE_AGP | /* DRIVER_USE_MTRR |*/
-	    DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_IRQ_VBL,
+	    DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_IRQ_VBL |
+	    DRIVER_IRQ_VBL2,
 	.load = i915_driver_load,
 	.lastclose = i915_driver_lastclose,
 	.preclose = i915_driver_preclose,
 	.device_is_agp = i915_driver_device_is_agp,
 	.vblank_wait = i915_driver_vblank_wait,
+	.vblank_wait2 = i915_driver_vblank_wait2,
 	.irq_preinstall = i915_driver_irq_preinstall,
 	.irq_postinstall = i915_driver_irq_postinstall,
 	.irq_uninstall = i915_driver_irq_uninstall,