drm/i915: Manage PIPESTAT to control vblank interrupts instead of IMR.

The pipestat fields affect reporting of all vblank-related interrupts, so we
have to reset them during the irq_handler, and while enabling vblank
interrupts.  Otherwise, if a pipe status field had been set to non-zero
before enabling reporting, we would never see an interrupt again.

This patch adds i915_enable_pipestat and i915_disable_pipestat to abstract
out the steps needed to change the reported interrupts.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 8 insertions, 10 deletions

diff --git a/drivers/gpu/drm/i915/i915_opregion.c b/drivers/gpu/drm/i915/i915_opregion.c
index 1787a0c7e3ab..13ae731a33db 100644
--- a/drivers/gpu/drm/i915/i915_opregion.c
+++ b/drivers/gpu/drm/i915/i915_opregion.c
@@ -235,17 +235,15 @@ void opregion_enable_asle(struct drm_device *dev)
         struct opregion_asle *asle = dev_priv->opregion.asle;
 
         if (asle) {
-                u32 pipeb_stats = I915_READ(PIPEBSTAT);
                 if (IS_MOBILE(dev)) {
-                        /* Many devices trigger events with a write to the
-                           legacy backlight controller, so we need to ensure
-                           that it's able to generate interrupts */
-                        I915_WRITE(PIPEBSTAT, pipeb_stats |=
-                                   I915_LEGACY_BLC_EVENT_ENABLE);
-                        i915_enable_irq(dev_priv, I915_ASLE_INTERRUPT |
-                                        I915_DISPLAY_PIPE_B_EVENT_INTERRUPT);
-                } else
-                        i915_enable_irq(dev_priv, I915_ASLE_INTERRUPT);
+                        unsigned long irqflags;
+
+                        spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
+                        i915_enable_pipestat(dev_priv, 1,
+                                             I915_LEGACY_BLC_EVENT_ENABLE);
+                        spin_unlock_irqrestore(&dev_priv->user_irq_lock,
+                                               irqflags);
+                }
 
                 asle->tche = ASLE_ALS_EN | ASLE_BLC_EN | ASLE_PFIT_EN |
                         ASLE_PFMB_EN;