drm: Rework vblank-wait handling to allow interrupt reduction.

Previously, drivers supporting vblank interrupt waits would run the interrupt
all the time, or all the time that any 3d client was running, preventing the
CPU from sleeping for long when the system was otherwise idle.  Now, interrupts
are disabled any time that no client is waiting on a vblank event. The new
method uses vblank counters on the chipsets when the interrupts are turned
off, rather than counting interrupts, so that we can continue to present
accurate vblank numbers.

Co-author: Michel Dänzer <michel@tungstengraphics.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 29115450ee46..63c6803d471b 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -673,7 +673,7 @@ static int i915_getparam(struct drm_device *dev, void *data,
 
         switch (param->param) {
         case I915_PARAM_IRQ_ACTIVE:
-                value = dev->irq_enabled;
+                value = dev->pdev->irq ? 1 : 0;
                 break;
         case I915_PARAM_ALLOW_BATCHBUFFER:
                 value = dev_priv->allow_batchbuffer ? 1 : 0;
@@ -808,7 +808,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
          * and the registers being closely associated.
          */
         if (!IS_I945G(dev) && !IS_I945GM(dev))
-                pci_enable_msi(dev->pdev);
+                if (pci_enable_msi(dev->pdev))
+                        DRM_ERROR("failed to enable MSI\n");
 
         intel_opregion_init(dev);