From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Add a vblank notify mechanism where you can ask for a callback when a
specific frame counter value has been passed.
This could be used for various things like FBC, IPS, watermarks,
and updating single buffered display registers from the interrupt
handler (eg. gamma).
As gen2 doesn't have a hardware frame counter we use the software vblank
counter drm core procvides. This is rather racy, but for something like
FBC it doesn't matter too much. For gen2 we could just scheudle the FBC
enable happen a frame later than on other gens. That should paper over
the races sufficiently.
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_irq.c | 8 +++
drivers/gpu/drm/i915/intel_display.c | 132 +++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_drv.h | 16 +++++
3 files changed, 156 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 218f011..a908a55 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1736,7 +1736,15 @@ static bool intel_pipe_handle_vblank(struct drm_device *dev, enum pipe pipe)
if (!drm_handle_vblank(dev, pipe))
return false;
+ if (!drm_core_check_feature(dev, DRIVER_MODESET))
+ return true;
+
crtc = to_intel_crtc(intel_get_crtc_for_pipe(dev, pipe));
+
+ spin_lock(&crtc->lock);
+ intel_vblank_notify_check(crtc);
+ spin_unlock(&crtc->lock);
+
wake_up(&crtc->vbl_wait);
return true;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5e8e711..be3ee69 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11499,6 +11499,9 @@ static void intel_crtc_init(struct drm_device *dev, int pipe)
init_waitqueue_head(&intel_crtc->vbl_wait);
+ spin_lock_init(&intel_crtc->lock);
+ INIT_LIST_HEAD(&intel_crtc->vblank_notify_list);
+
BUG_ON(pipe >= ARRAY_SIZE(dev_priv->plane_to_crtc_mapping) ||
dev_priv->plane_to_crtc_mapping[intel_crtc->plane] != NULL);
dev_priv->plane_to_crtc_mapping[intel_crtc->plane] = &intel_crtc->base;
@@ -13051,3 +13054,132 @@ intel_display_print_error_state(struct drm_i915_error_state_buf *m,
err_printf(m, " VSYNC: %08x\n", error->transcoder[i].vsync);
}
}
+
+/* is a after b? */
+static bool vbl_count_after_eq(struct drm_device *dev, u32 a, u32 b)
+{
+ u32 mask = dev->max_vblank_count;
+
+ /* now hardware counter on gen2 */
+ if (mask == 0)
+ mask = -1;
+
+ mask &= (mask >> 1);
+
+ return !((a - b) & mask);
+}
+
+static void intel_vblank_notify_complete(struct intel_vblank_notify *notify)
+{
+ struct intel_crtc *crtc = notify->crtc;
+ struct drm_device *dev = crtc->base.dev;
+
+ assert_spin_locked(&crtc->lock);
+
+ drm_vblank_put(dev, crtc->pipe);
+ list_del(¬ify->list);
+ notify->crtc = NULL;
+}
+
+void intel_vblank_notify_check(struct intel_crtc *crtc)
+{
+ struct drm_device *dev = crtc->base.dev;
+ struct drm_vblank_crtc *vblank =
+ &dev->vblank[drm_crtc_index(&crtc->base)];
+ struct intel_vblank_notify *notify, *next;
+ u32 vbl_count;
+
+ assert_spin_locked(&crtc->lock);
+
+ if (list_empty(&crtc->vblank_notify_list))
+ return;
+
+ /* no hardware frame counter on gen2 */
+ if (dev->max_vblank_count == 0)
+ vbl_count = atomic_read(&vblank->count);
+ else
+ vbl_count = dev->driver->get_vblank_counter(dev, crtc->pipe);
+
+ list_for_each_entry_safe(notify, next, &crtc->vblank_notify_list, list) {
+ if (!vbl_count_after_eq(dev, vbl_count, notify->vbl_count))
+ continue;
+
+ intel_vblank_notify_complete(notify);
+ notify->notify(notify);
+ }
+}
+
+int intel_vblank_notify_add(struct intel_crtc *crtc,
+ struct intel_vblank_notify *notify)
+{
+ struct drm_device *dev = crtc->base.dev;
+ unsigned long irqflags;
+ u32 vbl_count;
+ int ret;
+
+ if (WARN_ON(notify->crtc))
+ return -EINVAL;
+
+ ret = drm_vblank_get(dev, crtc->pipe);
+ if (ret)
+ return ret;
+
+ spin_lock_irqsave(&crtc->lock, irqflags);
+
+ notify->crtc = crtc;
+ list_add(¬ify->list, &crtc->vblank_notify_list);
+
+ /* no hardware frame counter on gen2 */
+ if (dev->max_vblank_count == 0) {
+ struct drm_vblank_crtc *vblank =
+ &dev->vblank[drm_crtc_index(&crtc->base)];
+
+ vbl_count = atomic_read(&vblank->count);
+ } else {
+ vbl_count = dev->driver->get_vblank_counter(dev, crtc->pipe);
+ }
+
+ if (vbl_count_after_eq(dev, vbl_count, notify->vbl_count)) {
+ intel_vblank_notify_complete(notify);
+ notify->notify(notify);
+ }
+
+ spin_unlock_irqrestore(&crtc->lock, irqflags);
+
+ return 0;
+}
+
+bool intel_vblank_notify_pending(struct intel_vblank_notify *notify)
+{
+ return notify->crtc != NULL;
+}
+
+void intel_vblank_notify_cancel(struct intel_vblank_notify *notify)
+{
+ struct intel_crtc *crtc = ACCESS_ONCE(notify->crtc);
+ unsigned long irqflags;
+
+ if (!crtc)
+ return;
+
+ spin_lock_irqsave(&crtc->lock, irqflags);
+ if (notify->crtc)
+ intel_vblank_notify_complete(notify);
+ spin_unlock_irqrestore(&crtc->lock, irqflags);
+}
+
+u32 intel_crtc_vbl_count_rel_to_abs(struct intel_crtc *crtc, u32 rel)
+{
+ struct drm_device *dev = crtc->base.dev;
+
+ /* now hardware counter on gen2 */
+ if (dev->max_vblank_count == 0) {
+ struct drm_vblank_crtc *vblank =
+ &dev->vblank[drm_crtc_index(&crtc->base)];
+
+ return atomic_read(&vblank->count) + rel;
+ }
+
+ return (dev->driver->get_vblank_counter(dev, crtc->pipe) + rel) &
+ dev->max_vblank_count;
+}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index ab5962b..c93626b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -358,6 +358,13 @@ struct intel_pipe_wm {
bool sprites_scaled;
};
+struct intel_vblank_notify {
+ void (*notify)(struct intel_vblank_notify *notify);
+ struct intel_crtc *crtc;
+ struct list_head list;
+ u32 vbl_count;
+};
+
struct intel_mmio_flip {
u32 seqno;
u32 ring_id;
@@ -417,6 +424,9 @@ struct intel_crtc {
int scanline_offset;
struct intel_mmio_flip mmio_flip;
+
+ struct list_head vblank_notify_list;
+ spinlock_t lock;
};
struct intel_plane_wm_parameters {
@@ -811,6 +821,12 @@ void intel_mode_from_pipe_config(struct drm_display_mode *mode,
struct intel_crtc_config *pipe_config);
int intel_format_to_fourcc(int format);
void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc);
+int intel_vblank_notify_add(struct intel_crtc *crtc,
+ struct intel_vblank_notify *notify);
+void intel_vblank_notify_cancel(struct intel_vblank_notify *notify);
+bool intel_vblank_notify_pending(struct intel_vblank_notify *notify);
+void intel_vblank_notify_check(struct intel_crtc *crtc);
+u32 intel_crtc_vbl_count_rel_to_abs(struct intel_crtc *crtc, u32 rel);
/* intel_dp.c */
--
1.8.5.5
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