@@ -324,7 +324,7 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data)
seq_printf(m, "No flip due on pipe %c (plane %c)\n",
pipe, plane);
} else {
- if (!work->pending) {
+ if (atomic_read(&work->pending) < INTEL_FLIP_COMPLETE) {
seq_printf(m, "Flip queued on pipe %c (plane %c)\n",
pipe, plane);
} else {
@@ -335,7 +335,7 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data)
seq_printf(m, "Stall check enabled, ");
else
seq_printf(m, "Stall check waiting for page flip ioctl, ");
- seq_printf(m, "%d prepares\n", work->pending);
+ seq_printf(m, "%d prepares\n", atomic_read(&work->pending));
if (work->old_fb_obj) {
struct drm_i915_gem_object *obj = work->old_fb_obj;
@@ -1336,7 +1336,9 @@ static void i915_pageflip_stall_check(struct drm_device *dev, int pipe)
spin_lock_irqsave(&dev->event_lock, flags);
work = intel_crtc->unpin_work;
- if (work == NULL || work->pending || !work->enable_stall_check) {
+ if (work == NULL ||
+ atomic_read(&work->pending) >= INTEL_FLIP_COMPLETE ||
+ !work->enable_stall_check) {
/* Either the pending flip IRQ arrived, or we're too early. Don't check */
spin_unlock_irqrestore(&dev->event_lock, flags);
return;
@@ -5906,11 +5906,18 @@ static void do_intel_finish_page_flip(struct drm_device *dev,
spin_lock_irqsave(&dev->event_lock, flags);
work = intel_crtc->unpin_work;
- if (work == NULL || !work->pending) {
+
+ /* Ensure we don't miss a work->pending update ... */
+ smp_rmb();
+
+ if (work == NULL || atomic_read(&work->pending) < INTEL_FLIP_COMPLETE) {
spin_unlock_irqrestore(&dev->event_lock, flags);
return;
}
+ /* and that the unpin work is consistent wrt ->pending. */
+ smp_rmb();
+
intel_crtc->unpin_work = NULL;
if (work->event) {
@@ -5982,16 +5989,25 @@ void intel_prepare_page_flip(struct drm_device *dev, int plane)
to_intel_crtc(dev_priv->plane_to_crtc_mapping[plane]);
unsigned long flags;
+ /* NB: An MMIO update of the plane base pointer will also
+ * generate a page-flip completion irq, i.e. every modeset
+ * is also accompanied by a spurious intel_prepare_page_flip().
+ */
spin_lock_irqsave(&dev->event_lock, flags);
- if (intel_crtc->unpin_work) {
- if ((++intel_crtc->unpin_work->pending) > 1)
- DRM_ERROR("Prepared flip multiple times\n");
- } else {
- DRM_DEBUG_DRIVER("preparing flip with no unpin work?\n");
- }
+ if (intel_crtc->unpin_work)
+ atomic_inc_not_zero(&intel_crtc->unpin_work->pending);
spin_unlock_irqrestore(&dev->event_lock, flags);
}
+inline static void intel_mark_page_flip_active(struct intel_crtc *intel_crtc)
+{
+ /* Ensure that the work item is consistent when activating it ... */
+ smp_wmb();
+ atomic_set(&intel_crtc->unpin_work->pending, INTEL_FLIP_PENDING);
+ /* and that it is marked active as soon as the irq could fire. */
+ smp_wmb();
+}
+
static int intel_gen2_queue_flip(struct drm_device *dev,
struct drm_crtc *crtc,
struct drm_framebuffer *fb,
@@ -6029,6 +6045,8 @@ static int intel_gen2_queue_flip(struct drm_device *dev,
intel_ring_emit(ring, fb->pitches[0]);
intel_ring_emit(ring, obj->gtt_offset + offset);
intel_ring_emit(ring, 0); /* aux display base address, unused */
+
+ intel_mark_page_flip_active(intel_crtc);
intel_ring_advance(ring);
return 0;
@@ -6073,6 +6091,7 @@ static int intel_gen3_queue_flip(struct drm_device *dev,
intel_ring_emit(ring, obj->gtt_offset + offset);
intel_ring_emit(ring, MI_NOOP);
+ intel_mark_page_flip_active(intel_crtc);
intel_ring_advance(ring);
return 0;
@@ -6117,6 +6136,8 @@ static int intel_gen4_queue_flip(struct drm_device *dev,
pf = 0;
pipesrc = I915_READ(PIPESRC(intel_crtc->pipe)) & 0x0fff0fff;
intel_ring_emit(ring, pf | pipesrc);
+
+ intel_mark_page_flip_active(intel_crtc);
intel_ring_advance(ring);
return 0;
@@ -6159,6 +6180,8 @@ static int intel_gen6_queue_flip(struct drm_device *dev,
pf = 0;
pipesrc = I915_READ(PIPESRC(intel_crtc->pipe)) & 0x0fff0fff;
intel_ring_emit(ring, pf | pipesrc);
+
+ intel_mark_page_flip_active(intel_crtc);
intel_ring_advance(ring);
return 0;
@@ -6213,6 +6236,8 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
intel_ring_emit(ring, (fb->pitches[0] | obj->tiling_mode));
intel_ring_emit(ring, (obj->gtt_offset));
intel_ring_emit(ring, (MI_NOOP));
+
+ intel_mark_page_flip_active(intel_crtc);
intel_ring_advance(ring);
return 0;
@@ -323,7 +323,10 @@ struct intel_unpin_work {
struct drm_i915_gem_object *old_fb_obj;
struct drm_i915_gem_object *pending_flip_obj;
struct drm_pending_vblank_event *event;
- int pending;
+ atomic_t pending;
+#define INTEL_FLIP_INACTIVE 0
+#define INTEL_FLIP_PENDING 1
+#define INTEL_FLIP_COMPLETE 2
bool enable_stall_check;
};