[PATCH 2/2] drm/vkms: Add 'virtual_hw' module option

[Gabriela Bittencourt]

Add Virtual Vblank, virtual hardware module option ('virtual_hw')
allows to skip the timing of vblank routine.

Signed-off-by: Gabriela Bittencourt <gabrielabittencourt00 at gmail.com>
---
 drivers/gpu/drm/vkms/vkms_crtc.c | 28 ++++++++++++++++++++++++++--
 drivers/gpu/drm/vkms/vkms_drv.c  | 13 +++++++++++--
 drivers/gpu/drm/vkms/vkms_drv.h  |  2 ++
 3 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index a72769b81efe..d4aa1ed93bf2 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -58,6 +58,18 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
 	return HRTIMER_RESTART;
 }
 
+static void vkms_virtual_vblank_simulate(struct vkms_output *output,
+					 struct drm_crtc *crtc)
+{
+	struct vkms_crtc_state *state;
+	bool ret;
+
+	state = output->composer_state;
+	ret = vkms_queue_compose_worker(output, state);
+	if (!ret)
+		DRM_DEBUG_DRIVER("Composer worker already queued\n");
+}
+
 static int vkms_enable_vblank(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
@@ -214,16 +226,25 @@ static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
 	return 0;
 }
 
+static bool vkms_crtc_atomic_check_vblank_enable(struct drm_crtc *crtc)
+{
+	struct vkms_output *vkms_out = drm_crtc_to_vkms_output(crtc);
+
+	return (!vkms_out->disable_vblank);
+}
+
 static void vkms_crtc_atomic_enable(struct drm_crtc *crtc,
 				    struct drm_crtc_state *old_state)
 {
-	drm_crtc_vblank_on(crtc);
+	if (vkms_crtc_atomic_check_vblank_enable(crtc))
+		drm_crtc_vblank_on(crtc);
 }
 
 static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,
 				     struct drm_crtc_state *old_state)
 {
-	drm_crtc_vblank_off(crtc);
+	if (vkms_crtc_atomic_check_vblank_enable(crtc))
+		drm_crtc_vblank_off(crtc);
 }
 
 static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
@@ -258,6 +279,9 @@ static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
 	vkms_output->composer_state = to_vkms_crtc_state(crtc->state);
 
 	spin_unlock_irq(&vkms_output->lock);
+
+	if (vkms_output->disable_vblank)
+		vkms_virtual_vblank_simulate(vkms_output, crtc);
 }
 
 static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = {
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index eef85f1a0ce5..f7c25961b083 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -39,6 +39,11 @@ bool enable_cursor;
 module_param_named(enable_cursor, enable_cursor, bool, 0444);
 MODULE_PARM_DESC(enable_cursor, "Enable/Disable cursor support");
 
+bool virtual_hw;
+module_param_named(virtual_hw, virtual_hw, bool, 0444);
+MODULE_PARM_DESC(virtual_hw,
+		 "Enable virtual hardware mode / Disable vblank");
+
 static const struct file_operations vkms_driver_fops = {
 	.owner		= THIS_MODULE,
 	.open		= drm_open,
@@ -168,9 +173,13 @@ static int __init vkms_init(void)
 		goto out_put;
 	}
 
-	vkms_device->drm.irq_enabled = true;
+	vkms_device->output.disable_vblank = virtual_hw;
+	vkms_device->drm.irq_enabled = !virtual_hw;
+
+	if (virtual_hw)
+		DRM_INFO("Virtual hardware mode enabled");
 
-	ret = drm_vblank_init(&vkms_device->drm, 1);
+	ret = (virtual_hw) ? 0 : drm_vblank_init(&vkms_device->drm, 1);
 	if (ret) {
 		DRM_ERROR("Failed to vblank\n");
 		goto out_put;
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index eda04ffba7b1..52ad8e06adc5 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -19,6 +19,7 @@
 #define YRES_MAX  8192
 
 extern bool enable_cursor;
+extern bool virtual_hw;
 
 struct vkms_composer {
 	struct drm_framebuffer fb;
@@ -64,6 +65,7 @@ struct vkms_output {
 	struct drm_encoder encoder;
 	struct drm_connector connector;
 	struct hrtimer vblank_hrtimer;
+	bool disable_vblank;
 	ktime_t period_ns;
 	struct drm_pending_vblank_event *event;
 	/* ordered wq for composer_work */
-- 
2.25.1