diff mbox series

[v4,4/4] drm/vkms: add overlay support

Message ID 8261bf93d8a0e3ffaf81d8e7c9b3e9c229116be3.1619250933.git.melissa.srw@gmail.com (mailing list archive)
State New, archived
Headers show
Series drm/vkms: add overlay plane support | expand

Commit Message

Melissa Wen April 24, 2021, 8:26 a.m. UTC
Add support to overlay plane, in addition to primary and cursor
planes. In this approach, the plane composition still requires an
active primary plane and planes are composed associatively in the
order: (primary <- overlay) <- cursor

It enables to run the following IGT tests successfully:
- kms_plane_cursor:
  - pipe-A-[overlay, primary, viewport]-size-[64, 128, 256]
- kms_atomic:
  - plane-overlay-legacy
and preserves the successful execution of kms_cursor_crc,
kms_writeback and kms_flip

Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/vkms/vkms_composer.c | 27 +++++++++++++++++----------
 drivers/gpu/drm/vkms/vkms_drv.c      |  5 +++++
 drivers/gpu/drm/vkms/vkms_drv.h      |  1 +
 drivers/gpu/drm/vkms/vkms_output.c   | 11 ++++++++++-
 drivers/gpu/drm/vkms/vkms_plane.c    | 15 ++++++++++++---
 5 files changed, 45 insertions(+), 14 deletions(-)

Comments

Pekka Paalanen April 26, 2021, 8:07 a.m. UTC | #1
On Sat, 24 Apr 2021 05:26:10 -0300
Melissa Wen <melissa.srw@gmail.com> wrote:

> Add support to overlay plane, in addition to primary and cursor
> planes. In this approach, the plane composition still requires an
> active primary plane and planes are composed associatively in the
> order: (primary <- overlay) <- cursor
> 
> It enables to run the following IGT tests successfully:
> - kms_plane_cursor:
>   - pipe-A-[overlay, primary, viewport]-size-[64, 128, 256]
> - kms_atomic:
>   - plane-overlay-legacy
> and preserves the successful execution of kms_cursor_crc,
> kms_writeback and kms_flip
> 
> Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Hi,

just curious, when you need to compute a CRC without having a writeback
connector output, where do you write the blended result in order to
compute CRC?


Thanks,
pq

> ---
>  drivers/gpu/drm/vkms/vkms_composer.c | 27 +++++++++++++++++----------
>  drivers/gpu/drm/vkms/vkms_drv.c      |  5 +++++
>  drivers/gpu/drm/vkms/vkms_drv.h      |  1 +
>  drivers/gpu/drm/vkms/vkms_output.c   | 11 ++++++++++-
>  drivers/gpu/drm/vkms/vkms_plane.c    | 15 ++++++++++++---
>  5 files changed, 45 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> index 7e01bc39d2a1..1b510f3dbcbf 100644
> --- a/drivers/gpu/drm/vkms/vkms_composer.c
> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> @@ -176,11 +176,12 @@ static void compose_plane(struct vkms_composer *primary_composer,
>  
>  static int compose_active_planes(void **vaddr_out,
>  				 struct vkms_composer *primary_composer,
> -				 struct vkms_composer *cursor_composer)
> +				 struct vkms_crtc_state *crtc_state)
>  {
>  	struct drm_framebuffer *fb = &primary_composer->fb;
>  	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
>  	struct drm_gem_shmem_object *shmem_obj = to_drm_gem_shmem_obj(gem_obj);
> +	int i;
>  
>  	if (!*vaddr_out) {
>  		*vaddr_out = kzalloc(shmem_obj->base.size, GFP_KERNEL);
> @@ -195,8 +196,14 @@ static int compose_active_planes(void **vaddr_out,
>  
>  	memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);
>  
> -	if (cursor_composer)
> -		compose_plane(primary_composer, cursor_composer, *vaddr_out);
> +	/* If there are other planes besides primary, we consider the active
> +	 * planes should be in z-order and compose them associatively:
> +	 * ((primary <- overlay) <- cursor)
> +	 */
> +	for (i = 1; i < crtc_state->num_active_planes; i++)
> +		compose_plane(primary_composer,
> +			      crtc_state->active_planes[i]->composer,
> +			      *vaddr_out);
>  
>  	return 0;
>  }
> @@ -218,7 +225,7 @@ void vkms_composer_worker(struct work_struct *work)
>  	struct drm_crtc *crtc = crtc_state->base.crtc;
>  	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
>  	struct vkms_composer *primary_composer = NULL;
> -	struct vkms_composer *cursor_composer = NULL;
> +	struct vkms_plane_state *act_plane = NULL;
>  	bool crc_pending, wb_pending;
>  	void *vaddr_out = NULL;
>  	u32 crc32 = 0;
> @@ -242,11 +249,11 @@ void vkms_composer_worker(struct work_struct *work)
>  	if (!crc_pending)
>  		return;
>  
> -	if (crtc_state->num_active_planes >= 1)
> -		primary_composer = crtc_state->active_planes[0]->composer;
> -
> -	if (crtc_state->num_active_planes == 2)
> -		cursor_composer = crtc_state->active_planes[1]->composer;
> +	if (crtc_state->num_active_planes >= 1) {
> +		act_plane = crtc_state->active_planes[0];
> +		if (act_plane->base.plane->type == DRM_PLANE_TYPE_PRIMARY)
> +			primary_composer = act_plane->composer;
> +	}
>  
>  	if (!primary_composer)
>  		return;
> @@ -255,7 +262,7 @@ void vkms_composer_worker(struct work_struct *work)
>  		vaddr_out = crtc_state->active_writeback;
>  
>  	ret = compose_active_planes(&vaddr_out, primary_composer,
> -				    cursor_composer);
> +				    crtc_state);
>  	if (ret) {
>  		if (ret == -EINVAL && !wb_pending)
>  			kfree(vaddr_out);
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index 2173b82606f6..027ffe759440 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -44,6 +44,10 @@ static bool enable_writeback = true;
>  module_param_named(enable_writeback, enable_writeback, bool, 0444);
>  MODULE_PARM_DESC(enable_writeback, "Enable/Disable writeback connector support");
>  
> +static bool enable_overlay;
> +module_param_named(enable_overlay, enable_overlay, bool, 0444);
> +MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support");
> +
>  DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
>  
>  static void vkms_release(struct drm_device *dev)
> @@ -198,6 +202,7 @@ static int __init vkms_init(void)
>  
>  	config->cursor = enable_cursor;
>  	config->writeback = enable_writeback;
> +	config->overlay = enable_overlay;
>  
>  	return vkms_create(config);
>  }
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index 70fb79621617..ac8c9c2fa4ed 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -89,6 +89,7 @@ struct vkms_device;
>  struct vkms_config {
>  	bool writeback;
>  	bool cursor;
> +	bool overlay;
>  	/* only set when instantiated */
>  	struct vkms_device *dev;
>  };
> diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
> index 6979fbc7f821..04406bd3ff02 100644
> --- a/drivers/gpu/drm/vkms/vkms_output.c
> +++ b/drivers/gpu/drm/vkms/vkms_output.c
> @@ -39,7 +39,7 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
>  	struct drm_connector *connector = &output->connector;
>  	struct drm_encoder *encoder = &output->encoder;
>  	struct drm_crtc *crtc = &output->crtc;
> -	struct vkms_plane *primary, *cursor = NULL;
> +	struct vkms_plane *primary, *cursor = NULL, *overlay = NULL;
>  	int ret;
>  	int writeback;
>  
> @@ -47,6 +47,15 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
>  	if (IS_ERR(primary))
>  		return PTR_ERR(primary);
>  
> +	if (vkmsdev->config->overlay) {
> +		overlay = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_OVERLAY, index);
> +		if (IS_ERR(overlay))
> +			return PTR_ERR(overlay);
> +
> +		if (!overlay->base.possible_crtcs)
> +			overlay->base.possible_crtcs = drm_crtc_mask(crtc);
> +	}
> +
>  	if (vkmsdev->config->cursor) {
>  		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR, index);
>  		if (IS_ERR(cursor))
> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> index da4251aff67f..107521ace597 100644
> --- a/drivers/gpu/drm/vkms/vkms_plane.c
> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> @@ -133,7 +133,7 @@ static int vkms_plane_atomic_check(struct drm_plane *plane,
>  	if (IS_ERR(crtc_state))
>  		return PTR_ERR(crtc_state);
>  
> -	if (plane->type == DRM_PLANE_TYPE_CURSOR)
> +	if (plane->type != DRM_PLANE_TYPE_PRIMARY)
>  		can_position = true;
>  
>  	ret = drm_atomic_helper_check_plane_state(new_plane_state, crtc_state,
> @@ -200,14 +200,23 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
>  	const u32 *formats;
>  	int nformats;
>  
> -	if (type == DRM_PLANE_TYPE_CURSOR) {
> +	switch (type) {
> +	case DRM_PLANE_TYPE_PRIMARY:
> +		formats = vkms_formats;
> +		nformats = ARRAY_SIZE(vkms_formats);
> +		funcs = &vkms_primary_helper_funcs;
> +		break;
> +	case DRM_PLANE_TYPE_CURSOR:
> +	case DRM_PLANE_TYPE_OVERLAY:
>  		formats = vkms_plane_formats;
>  		nformats = ARRAY_SIZE(vkms_plane_formats);
>  		funcs = &vkms_primary_helper_funcs;
> -	} else {
> +		break;
> +	default:
>  		formats = vkms_formats;
>  		nformats = ARRAY_SIZE(vkms_formats);
>  		funcs = &vkms_primary_helper_funcs;
> +		break;
>  	}
>  
>  	plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 1 << index,
Melissa Wen April 26, 2021, 5:07 p.m. UTC | #2
On 04/26, Pekka Paalanen wrote:
> On Sat, 24 Apr 2021 05:26:10 -0300
> Melissa Wen <melissa.srw@gmail.com> wrote:
> 
> > Add support to overlay plane, in addition to primary and cursor
> > planes. In this approach, the plane composition still requires an
> > active primary plane and planes are composed associatively in the
> > order: (primary <- overlay) <- cursor
> > 
> > It enables to run the following IGT tests successfully:
> > - kms_plane_cursor:
> >   - pipe-A-[overlay, primary, viewport]-size-[64, 128, 256]
> > - kms_atomic:
> >   - plane-overlay-legacy
> > and preserves the successful execution of kms_cursor_crc,
> > kms_writeback and kms_flip
> > 
> > Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
> > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> 
> Hi,
> 
> just curious, when you need to compute a CRC without having a writeback
> connector output, where do you write the blended result in order to
> compute CRC?

Hi,

so, when no writeback output, an output frame is allocated in the
compose_planes functions to get the plane composition there, as shown
here: https://lkml.org/lkml/2020/8/30/163

Melissa

> 
> 
> Thanks,
> pq
> 
> > ---
> >  drivers/gpu/drm/vkms/vkms_composer.c | 27 +++++++++++++++++----------
> >  drivers/gpu/drm/vkms/vkms_drv.c      |  5 +++++
> >  drivers/gpu/drm/vkms/vkms_drv.h      |  1 +
> >  drivers/gpu/drm/vkms/vkms_output.c   | 11 ++++++++++-
> >  drivers/gpu/drm/vkms/vkms_plane.c    | 15 ++++++++++++---
> >  5 files changed, 45 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> > index 7e01bc39d2a1..1b510f3dbcbf 100644
> > --- a/drivers/gpu/drm/vkms/vkms_composer.c
> > +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> > @@ -176,11 +176,12 @@ static void compose_plane(struct vkms_composer *primary_composer,
> >  
> >  static int compose_active_planes(void **vaddr_out,
> >  				 struct vkms_composer *primary_composer,
> > -				 struct vkms_composer *cursor_composer)
> > +				 struct vkms_crtc_state *crtc_state)
> >  {
> >  	struct drm_framebuffer *fb = &primary_composer->fb;
> >  	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
> >  	struct drm_gem_shmem_object *shmem_obj = to_drm_gem_shmem_obj(gem_obj);
> > +	int i;
> >  
> >  	if (!*vaddr_out) {
> >  		*vaddr_out = kzalloc(shmem_obj->base.size, GFP_KERNEL);
> > @@ -195,8 +196,14 @@ static int compose_active_planes(void **vaddr_out,
> >  
> >  	memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);
> >  
> > -	if (cursor_composer)
> > -		compose_plane(primary_composer, cursor_composer, *vaddr_out);
> > +	/* If there are other planes besides primary, we consider the active
> > +	 * planes should be in z-order and compose them associatively:
> > +	 * ((primary <- overlay) <- cursor)
> > +	 */
> > +	for (i = 1; i < crtc_state->num_active_planes; i++)
> > +		compose_plane(primary_composer,
> > +			      crtc_state->active_planes[i]->composer,
> > +			      *vaddr_out);
> >  
> >  	return 0;
> >  }
> > @@ -218,7 +225,7 @@ void vkms_composer_worker(struct work_struct *work)
> >  	struct drm_crtc *crtc = crtc_state->base.crtc;
> >  	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
> >  	struct vkms_composer *primary_composer = NULL;
> > -	struct vkms_composer *cursor_composer = NULL;
> > +	struct vkms_plane_state *act_plane = NULL;
> >  	bool crc_pending, wb_pending;
> >  	void *vaddr_out = NULL;
> >  	u32 crc32 = 0;
> > @@ -242,11 +249,11 @@ void vkms_composer_worker(struct work_struct *work)
> >  	if (!crc_pending)
> >  		return;
> >  
> > -	if (crtc_state->num_active_planes >= 1)
> > -		primary_composer = crtc_state->active_planes[0]->composer;
> > -
> > -	if (crtc_state->num_active_planes == 2)
> > -		cursor_composer = crtc_state->active_planes[1]->composer;
> > +	if (crtc_state->num_active_planes >= 1) {
> > +		act_plane = crtc_state->active_planes[0];
> > +		if (act_plane->base.plane->type == DRM_PLANE_TYPE_PRIMARY)
> > +			primary_composer = act_plane->composer;
> > +	}
> >  
> >  	if (!primary_composer)
> >  		return;
> > @@ -255,7 +262,7 @@ void vkms_composer_worker(struct work_struct *work)
> >  		vaddr_out = crtc_state->active_writeback;
> >  
> >  	ret = compose_active_planes(&vaddr_out, primary_composer,
> > -				    cursor_composer);
> > +				    crtc_state);
> >  	if (ret) {
> >  		if (ret == -EINVAL && !wb_pending)
> >  			kfree(vaddr_out);
> > diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> > index 2173b82606f6..027ffe759440 100644
> > --- a/drivers/gpu/drm/vkms/vkms_drv.c
> > +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> > @@ -44,6 +44,10 @@ static bool enable_writeback = true;
> >  module_param_named(enable_writeback, enable_writeback, bool, 0444);
> >  MODULE_PARM_DESC(enable_writeback, "Enable/Disable writeback connector support");
> >  
> > +static bool enable_overlay;
> > +module_param_named(enable_overlay, enable_overlay, bool, 0444);
> > +MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support");
> > +
> >  DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
> >  
> >  static void vkms_release(struct drm_device *dev)
> > @@ -198,6 +202,7 @@ static int __init vkms_init(void)
> >  
> >  	config->cursor = enable_cursor;
> >  	config->writeback = enable_writeback;
> > +	config->overlay = enable_overlay;
> >  
> >  	return vkms_create(config);
> >  }
> > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> > index 70fb79621617..ac8c9c2fa4ed 100644
> > --- a/drivers/gpu/drm/vkms/vkms_drv.h
> > +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> > @@ -89,6 +89,7 @@ struct vkms_device;
> >  struct vkms_config {
> >  	bool writeback;
> >  	bool cursor;
> > +	bool overlay;
> >  	/* only set when instantiated */
> >  	struct vkms_device *dev;
> >  };
> > diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
> > index 6979fbc7f821..04406bd3ff02 100644
> > --- a/drivers/gpu/drm/vkms/vkms_output.c
> > +++ b/drivers/gpu/drm/vkms/vkms_output.c
> > @@ -39,7 +39,7 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
> >  	struct drm_connector *connector = &output->connector;
> >  	struct drm_encoder *encoder = &output->encoder;
> >  	struct drm_crtc *crtc = &output->crtc;
> > -	struct vkms_plane *primary, *cursor = NULL;
> > +	struct vkms_plane *primary, *cursor = NULL, *overlay = NULL;
> >  	int ret;
> >  	int writeback;
> >  
> > @@ -47,6 +47,15 @@ int vkms_output_init(struct vkms_device *vkmsdev, int index)
> >  	if (IS_ERR(primary))
> >  		return PTR_ERR(primary);
> >  
> > +	if (vkmsdev->config->overlay) {
> > +		overlay = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_OVERLAY, index);
> > +		if (IS_ERR(overlay))
> > +			return PTR_ERR(overlay);
> > +
> > +		if (!overlay->base.possible_crtcs)
> > +			overlay->base.possible_crtcs = drm_crtc_mask(crtc);
> > +	}
> > +
> >  	if (vkmsdev->config->cursor) {
> >  		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR, index);
> >  		if (IS_ERR(cursor))
> > diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> > index da4251aff67f..107521ace597 100644
> > --- a/drivers/gpu/drm/vkms/vkms_plane.c
> > +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> > @@ -133,7 +133,7 @@ static int vkms_plane_atomic_check(struct drm_plane *plane,
> >  	if (IS_ERR(crtc_state))
> >  		return PTR_ERR(crtc_state);
> >  
> > -	if (plane->type == DRM_PLANE_TYPE_CURSOR)
> > +	if (plane->type != DRM_PLANE_TYPE_PRIMARY)
> >  		can_position = true;
> >  
> >  	ret = drm_atomic_helper_check_plane_state(new_plane_state, crtc_state,
> > @@ -200,14 +200,23 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
> >  	const u32 *formats;
> >  	int nformats;
> >  
> > -	if (type == DRM_PLANE_TYPE_CURSOR) {
> > +	switch (type) {
> > +	case DRM_PLANE_TYPE_PRIMARY:
> > +		formats = vkms_formats;
> > +		nformats = ARRAY_SIZE(vkms_formats);
> > +		funcs = &vkms_primary_helper_funcs;
> > +		break;
> > +	case DRM_PLANE_TYPE_CURSOR:
> > +	case DRM_PLANE_TYPE_OVERLAY:
> >  		formats = vkms_plane_formats;
> >  		nformats = ARRAY_SIZE(vkms_plane_formats);
> >  		funcs = &vkms_primary_helper_funcs;
> > -	} else {
> > +		break;
> > +	default:
> >  		formats = vkms_formats;
> >  		nformats = ARRAY_SIZE(vkms_formats);
> >  		funcs = &vkms_primary_helper_funcs;
> > +		break;
> >  	}
> >  
> >  	plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 1 << index,
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
index 7e01bc39d2a1..1b510f3dbcbf 100644
--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -176,11 +176,12 @@  static void compose_plane(struct vkms_composer *primary_composer,
 
 static int compose_active_planes(void **vaddr_out,
 				 struct vkms_composer *primary_composer,
-				 struct vkms_composer *cursor_composer)
+				 struct vkms_crtc_state *crtc_state)
 {
 	struct drm_framebuffer *fb = &primary_composer->fb;
 	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
 	struct drm_gem_shmem_object *shmem_obj = to_drm_gem_shmem_obj(gem_obj);
+	int i;
 
 	if (!*vaddr_out) {
 		*vaddr_out = kzalloc(shmem_obj->base.size, GFP_KERNEL);
@@ -195,8 +196,14 @@  static int compose_active_planes(void **vaddr_out,
 
 	memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);
 
-	if (cursor_composer)
-		compose_plane(primary_composer, cursor_composer, *vaddr_out);
+	/* If there are other planes besides primary, we consider the active
+	 * planes should be in z-order and compose them associatively:
+	 * ((primary <- overlay) <- cursor)
+	 */
+	for (i = 1; i < crtc_state->num_active_planes; i++)
+		compose_plane(primary_composer,
+			      crtc_state->active_planes[i]->composer,
+			      *vaddr_out);
 
 	return 0;
 }
@@ -218,7 +225,7 @@  void vkms_composer_worker(struct work_struct *work)
 	struct drm_crtc *crtc = crtc_state->base.crtc;
 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 	struct vkms_composer *primary_composer = NULL;
-	struct vkms_composer *cursor_composer = NULL;
+	struct vkms_plane_state *act_plane = NULL;
 	bool crc_pending, wb_pending;
 	void *vaddr_out = NULL;
 	u32 crc32 = 0;
@@ -242,11 +249,11 @@  void vkms_composer_worker(struct work_struct *work)
 	if (!crc_pending)
 		return;
 
-	if (crtc_state->num_active_planes >= 1)
-		primary_composer = crtc_state->active_planes[0]->composer;
-
-	if (crtc_state->num_active_planes == 2)
-		cursor_composer = crtc_state->active_planes[1]->composer;
+	if (crtc_state->num_active_planes >= 1) {
+		act_plane = crtc_state->active_planes[0];
+		if (act_plane->base.plane->type == DRM_PLANE_TYPE_PRIMARY)
+			primary_composer = act_plane->composer;
+	}
 
 	if (!primary_composer)
 		return;
@@ -255,7 +262,7 @@  void vkms_composer_worker(struct work_struct *work)
 		vaddr_out = crtc_state->active_writeback;
 
 	ret = compose_active_planes(&vaddr_out, primary_composer,
-				    cursor_composer);
+				    crtc_state);
 	if (ret) {
 		if (ret == -EINVAL && !wb_pending)
 			kfree(vaddr_out);
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 2173b82606f6..027ffe759440 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -44,6 +44,10 @@  static bool enable_writeback = true;
 module_param_named(enable_writeback, enable_writeback, bool, 0444);
 MODULE_PARM_DESC(enable_writeback, "Enable/Disable writeback connector support");
 
+static bool enable_overlay;
+module_param_named(enable_overlay, enable_overlay, bool, 0444);
+MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support");
+
 DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
 
 static void vkms_release(struct drm_device *dev)
@@ -198,6 +202,7 @@  static int __init vkms_init(void)
 
 	config->cursor = enable_cursor;
 	config->writeback = enable_writeback;
+	config->overlay = enable_overlay;
 
 	return vkms_create(config);
 }
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 70fb79621617..ac8c9c2fa4ed 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -89,6 +89,7 @@  struct vkms_device;
 struct vkms_config {
 	bool writeback;
 	bool cursor;
+	bool overlay;
 	/* only set when instantiated */
 	struct vkms_device *dev;
 };
diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
index 6979fbc7f821..04406bd3ff02 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -39,7 +39,7 @@  int vkms_output_init(struct vkms_device *vkmsdev, int index)
 	struct drm_connector *connector = &output->connector;
 	struct drm_encoder *encoder = &output->encoder;
 	struct drm_crtc *crtc = &output->crtc;
-	struct vkms_plane *primary, *cursor = NULL;
+	struct vkms_plane *primary, *cursor = NULL, *overlay = NULL;
 	int ret;
 	int writeback;
 
@@ -47,6 +47,15 @@  int vkms_output_init(struct vkms_device *vkmsdev, int index)
 	if (IS_ERR(primary))
 		return PTR_ERR(primary);
 
+	if (vkmsdev->config->overlay) {
+		overlay = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_OVERLAY, index);
+		if (IS_ERR(overlay))
+			return PTR_ERR(overlay);
+
+		if (!overlay->base.possible_crtcs)
+			overlay->base.possible_crtcs = drm_crtc_mask(crtc);
+	}
+
 	if (vkmsdev->config->cursor) {
 		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR, index);
 		if (IS_ERR(cursor))
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index da4251aff67f..107521ace597 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -133,7 +133,7 @@  static int vkms_plane_atomic_check(struct drm_plane *plane,
 	if (IS_ERR(crtc_state))
 		return PTR_ERR(crtc_state);
 
-	if (plane->type == DRM_PLANE_TYPE_CURSOR)
+	if (plane->type != DRM_PLANE_TYPE_PRIMARY)
 		can_position = true;
 
 	ret = drm_atomic_helper_check_plane_state(new_plane_state, crtc_state,
@@ -200,14 +200,23 @@  struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 	const u32 *formats;
 	int nformats;
 
-	if (type == DRM_PLANE_TYPE_CURSOR) {
+	switch (type) {
+	case DRM_PLANE_TYPE_PRIMARY:
+		formats = vkms_formats;
+		nformats = ARRAY_SIZE(vkms_formats);
+		funcs = &vkms_primary_helper_funcs;
+		break;
+	case DRM_PLANE_TYPE_CURSOR:
+	case DRM_PLANE_TYPE_OVERLAY:
 		formats = vkms_plane_formats;
 		nformats = ARRAY_SIZE(vkms_plane_formats);
 		funcs = &vkms_primary_helper_funcs;
-	} else {
+		break;
+	default:
 		formats = vkms_formats;
 		nformats = ARRAY_SIZE(vkms_formats);
 		funcs = &vkms_primary_helper_funcs;
+		break;
 	}
 
 	plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 1 << index,