[RFC PATCH 7/7] drm/i915/gvt: Introduce HW Vblank interrupt to vGPU

Tina Zhang tina.zhang at intel.com
Mon Dec 3 07:35:22 UTC 2018


For each physical crtc, Gvt-g has a kernel thread to get the HW vblank
event on time and inject the interrupt event to the vGPUs which the
display planes of the crtc are assigned to.

Signed-off-by: Tina Zhang <tina.zhang at intel.com>
Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Cc: Zhi Wang <zhi.a.wang at intel.com>
---
 drivers/gpu/drm/i915/gvt/display.c   |  30 ++++++----
 drivers/gpu/drm/i915/gvt/display.h   |   3 +-
 drivers/gpu/drm/i915/gvt/gvt.c       | 112 +++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/gvt/gvt.h       |   3 +
 drivers/gpu/drm/i915/gvt/handlers.c  |   4 +-
 drivers/gpu/drm/i915/gvt/interrupt.c |  54 +++++++++++++++++
 drivers/gpu/drm/i915/gvt/interrupt.h |   2 +
 7 files changed, 193 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/display.c b/drivers/gpu/drm/i915/gvt/display.c
index e06d8d6..eec8336 100644
--- a/drivers/gpu/drm/i915/gvt/display.c
+++ b/drivers/gpu/drm/i915/gvt/display.c
@@ -358,7 +358,7 @@ static int setup_virtual_dp_monitor(struct intel_vgpu *vgpu, int port_num,
  * enabled/disabled virtual pipes.
  *
  */
-void intel_gvt_check_vblank_emulation(struct intel_gvt *gvt)
+void intel_gvt_check_vblank_emulation(struct intel_gvt *gvt, bool use_hw_vblank)
 {
 	struct intel_gvt_irq *irq = &gvt->irq;
 	struct intel_vgpu *vgpu;
@@ -369,25 +369,29 @@ void intel_gvt_check_vblank_emulation(struct intel_gvt *gvt)
 	for_each_active_vgpu(gvt, vgpu, id) {
 		for (pipe = 0; pipe < I915_MAX_PIPES; pipe++) {
 			if (pipe_is_enabled(vgpu, pipe)) {
-				found = true;
-				break;
+				if (use_hw_vblank) {
+					wake_up_process(gvt->vblank_thread[pipe]);
+				} else {
+					found = true;
+					break;
+				}
 			}
 		}
-		if (found)
-			break;
 	}
 
-	/* all the pipes are disabled */
-	if (!found)
-		hrtimer_cancel(&irq->vblank_timer.timer);
-	else
-		hrtimer_start(&irq->vblank_timer.timer,
-			ktime_add_ns(ktime_get(), irq->vblank_timer.period),
-			HRTIMER_MODE_ABS);
+	if (!use_hw_vblank) {
+		/* all the pipes are disabled */
+		if (!found)
+			hrtimer_cancel(&irq->vblank_timer.timer);
+		else
+			hrtimer_start(&irq->vblank_timer.timer,
+				      ktime_add_ns(ktime_get(), irq->vblank_timer.period),
+				      HRTIMER_MODE_ABS);
+	}
 	mutex_unlock(&gvt->lock);
 }
 
-static void emulate_vblank_on_pipe(struct intel_vgpu *vgpu, int pipe)
+void emulate_vblank_on_pipe(struct intel_vgpu *vgpu, int pipe)
 {
 	struct drm_i915_private *dev_priv = vgpu->gvt->dev_priv;
 	struct intel_vgpu_irq *irq = &vgpu->irq;
diff --git a/drivers/gpu/drm/i915/gvt/display.h b/drivers/gpu/drm/i915/gvt/display.h
index 5d929bb..e0a85df 100644
--- a/drivers/gpu/drm/i915/gvt/display.h
+++ b/drivers/gpu/drm/i915/gvt/display.h
@@ -187,12 +187,13 @@ static inline char *vgpu_edid_str(enum intel_vgpu_edid id)
 }
 
 void intel_gvt_emulate_vblank(struct intel_gvt *gvt);
-void intel_gvt_check_vblank_emulation(struct intel_gvt *gvt);
+void intel_gvt_check_vblank_emulation(struct intel_gvt *gvt, bool use_hw_vblank);
 
 int intel_vgpu_init_display(struct intel_vgpu *vgpu, u64 resolution);
 void intel_vgpu_reset_display(struct intel_vgpu *vgpu);
 void intel_vgpu_clean_display(struct intel_vgpu *vgpu);
 
+void emulate_vblank_on_pipe(struct intel_vgpu *vgpu, int pipe);
 int pipe_is_enabled(struct intel_vgpu *vgpu, int pipe);
 
 
diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
index 733a2a0..a017ac4 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.c
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -250,6 +250,94 @@ static void init_device_info(struct intel_gvt *gvt)
 	info->msi_cap_offset = pdev->msi_cap;
 }
 
+static int emulate_crtc_a_vblank_thread(void *data)
+{
+	struct intel_gvt *gvt = (struct intel_gvt *)data;
+	struct drm_device *dev = &gvt->dev_priv->drm;
+	struct intel_vgpu *vgpu;
+	struct completion vblank_done = gvt->vblank_done[PIPE_A];
+	int ret;
+	int id;
+
+	DRM_DEBUG_KMS("vblank service thread a start\n");
+
+	while (!kthread_should_stop()) {
+		init_completion(&vblank_done);
+retry:
+		ret = intel_gvt_register_HW_vblank_event(dev, &vblank_done, PIPE_A);
+		if (ret) {
+			goto retry;
+		}
+
+		/* wait for the complete */
+		wait_for_completion_interruptible(&vblank_done);
+
+		/* inject the vblank to gvt */
+		for_each_active_vgpu(gvt, vgpu, id)
+			emulate_vblank_on_pipe(vgpu, PIPE_A);
+	}
+
+	return 0;
+}
+
+static int emulate_crtc_b_vblank_thread(void *data)
+{
+	struct intel_gvt *gvt = (struct intel_gvt *)data;
+	struct drm_device *dev = &gvt->dev_priv->drm;
+	struct intel_vgpu *vgpu;
+	struct completion vblank_done = gvt->vblank_done[PIPE_B];
+	int ret;
+	int id;
+
+	DRM_DEBUG_KMS("vblank service thread b start\n");
+
+	while (!kthread_should_stop()) {
+		init_completion(&vblank_done);
+retry:
+		ret = intel_gvt_register_HW_vblank_event(dev, &vblank_done, PIPE_B);
+		if (ret)
+			goto retry;
+
+		/* wait for the complete */
+		wait_for_completion_interruptible(&vblank_done);
+
+		/* inject the vblank to gvt */
+		for_each_active_vgpu(gvt, vgpu, id)
+			emulate_vblank_on_pipe(vgpu, PIPE_B);
+	}
+
+	return 0;
+}
+
+static int emulate_crtc_c_vblank_thread(void *data)
+{
+	struct intel_gvt *gvt = (struct intel_gvt *)data;
+	struct drm_device *dev = &gvt->dev_priv->drm;
+	struct intel_vgpu *vgpu;
+	struct completion vblank_done = gvt->vblank_done[PIPE_C];
+	int ret;
+	int id;
+
+	DRM_DEBUG_KMS("vblank service thread c start\n");
+
+	while (!kthread_should_stop()) {
+		init_completion(&vblank_done);
+retry:
+		ret = intel_gvt_register_HW_vblank_event(dev, &vblank_done, PIPE_C);
+		if (ret)
+			goto retry;
+
+		/* wait for the complete */
+		wait_for_completion_interruptible(&vblank_done);
+
+		/* inject the vblank to gvt */
+		for_each_active_vgpu(gvt, vgpu, id)
+			emulate_vblank_on_pipe(vgpu, PIPE_C);
+	}
+
+	return 0;
+}
+
 static int gvt_service_thread(void *data)
 {
 	struct intel_gvt *gvt = (struct intel_gvt *)data;
@@ -285,6 +373,9 @@ static int gvt_service_thread(void *data)
 static void clean_service_thread(struct intel_gvt *gvt)
 {
 	kthread_stop(gvt->service_thread);
+	kthread_stop(gvt->vblank_thread[PIPE_A]);
+	kthread_stop(gvt->vblank_thread[PIPE_B]);
+	kthread_stop(gvt->vblank_thread[PIPE_C]);
 }
 
 static int init_service_thread(struct intel_gvt *gvt)
@@ -297,6 +388,27 @@ static int init_service_thread(struct intel_gvt *gvt)
 		gvt_err("fail to start service thread.\n");
 		return PTR_ERR(gvt->service_thread);
 	}
+
+	gvt->vblank_thread[PIPE_A] = kthread_create(emulate_crtc_a_vblank_thread,
+			gvt, "emulate_crtc_a_vblank_thread");
+	if (IS_ERR(gvt->vblank_thread[PIPE_A])) {
+		gvt_err("fail to start service thread.\n");
+		return PTR_ERR(gvt->vblank_thread[PIPE_A]);
+	}
+
+	gvt->vblank_thread[PIPE_B] = kthread_create(emulate_crtc_b_vblank_thread,
+			gvt, "emulate_crtc_b_vblank_thread");
+	if (IS_ERR(gvt->vblank_thread[PIPE_B])) {
+		gvt_err("fail to start service thread.\n");
+		return PTR_ERR(gvt->vblank_thread[PIPE_B]);
+	}
+
+	gvt->vblank_thread[PIPE_C] = kthread_create(emulate_crtc_c_vblank_thread,
+			gvt, "emulate_crtc_c_vblank_thread");
+	if (IS_ERR(gvt->vblank_thread[PIPE_C])) {
+		gvt_err("fail to start service thread.\n");
+		return PTR_ERR(gvt->vblank_thread[PIPE_C]);
+	}
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index 0ab10b0..96903d2 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -356,6 +356,9 @@ struct intel_gvt {
 
 	/* vGPU plane assignment */
 	struct assigned_plane assigned_plane[I915_MAX_PIPES][I915_MAX_PLANES];
+
+	struct task_struct *vblank_thread[I915_MAX_PIPES];
+	struct completion vblank_done[I915_MAX_PIPES];
 };
 
 static inline struct intel_gvt *to_gvt(struct drm_i915_private *i915)
diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
index 89a22a5..4ad6611 100644
--- a/drivers/gpu/drm/i915/gvt/handlers.c
+++ b/drivers/gpu/drm/i915/gvt/handlers.c
@@ -449,10 +449,12 @@ static int pipeconf_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 		vgpu_vreg(vgpu, offset) |= I965_PIPECONF_ACTIVE;
 	else
 		vgpu_vreg(vgpu, offset) &= ~I965_PIPECONF_ACTIVE;
+
 	/* vgpu_lock already hold by emulate mmio r/w */
 	mutex_unlock(&vgpu->vgpu_lock);
-	intel_gvt_check_vblank_emulation(vgpu->gvt);
+	intel_gvt_check_vblank_emulation(vgpu->gvt, true);
 	mutex_lock(&vgpu->vgpu_lock);
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/i915/gvt/interrupt.c b/drivers/gpu/drm/i915/gvt/interrupt.c
index 5daa23a..cb92ce4 100644
--- a/drivers/gpu/drm/i915/gvt/interrupt.c
+++ b/drivers/gpu/drm/i915/gvt/interrupt.c
@@ -633,6 +633,60 @@ void intel_vgpu_trigger_virtual_event(struct intel_vgpu *vgpu,
 	ops->check_pending_irq(vgpu);
 }
 
+static void release_vblank_event(struct completion *completion)
+{
+	;
+}
+
+int intel_gvt_register_HW_vblank_event(struct drm_device *dev,
+				     struct completion *vblank_done, int pipe)
+{
+	struct drm_pending_vblank_event *e;
+	struct drm_crtc *crtc;
+	unsigned long flags;
+	int ret;
+
+	DRM_DEBUG_KMS("%s begin with pipe %d, com %p, dev %p", __func__, pipe, vblank_done, dev);
+
+	crtc = drm_crtc_from_index(dev, pipe);
+	if (!crtc) {
+		DRM_ERROR("cannot get crtc %d\n", pipe);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = drm_crtc_vblank_get(crtc);
+	if (ret) {
+		DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
+		goto out;
+	}
+
+	e = kzalloc(sizeof *e, GFP_KERNEL);
+	if (!e) {
+		drm_crtc_vblank_put(crtc);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* create a vblank event */
+	e->event.base.type = DRM_EVENT_VBLANK;
+	e->event.base.length = sizeof(e->event);
+	e->pipe = pipe;
+	e->base.completion = vblank_done;
+	e->base.completion_release = release_vblank_event;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+	e->sequence = drm_crtc_accurate_vblank_count(crtc) + 1;
+
+	/* add the event to vblank list */
+	list_add_tail(&e->base.link, &dev->vblank_event_list);
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+
+	DRM_DEBUG_KMS("%s: success \n", __func__);
+out:
+	return ret;
+}
+
 static void init_events(
 	struct intel_gvt_irq *irq)
 {
diff --git a/drivers/gpu/drm/i915/gvt/interrupt.h b/drivers/gpu/drm/i915/gvt/interrupt.h
index 5313fb1..ed4936e 100644
--- a/drivers/gpu/drm/i915/gvt/interrupt.h
+++ b/drivers/gpu/drm/i915/gvt/interrupt.h
@@ -213,6 +213,8 @@ struct intel_gvt_irq {
 
 int intel_gvt_init_irq(struct intel_gvt *gvt);
 void intel_gvt_clean_irq(struct intel_gvt *gvt);
+int intel_gvt_register_HW_vblank_event(struct drm_device *dev,
+				 struct completion *vblank_done, int pipe);
 
 void intel_vgpu_trigger_virtual_event(struct intel_vgpu *vgpu,
 	enum intel_gvt_event_type event);
-- 
2.7.4



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