Re: [PATCH v3 4/4] drm/vkms: add overlay support

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Apr 13, 2021 at 04:56:02AM -0300, Melissa Wen 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>
> ---
>  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    | 14 +++++++++++---
>  5 files changed, 44 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> index 7fe1fdb3af39..73ce1d381737 100644
> --- a/drivers/gpu/drm/vkms/vkms_composer.c
> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> @@ -158,11 +158,12 @@ static void compose_planes(struct vkms_composer *primary_composer,
>  
>  static int composite(void **vaddr_out,

Ok this was done in patch 2, but I think the names here need a bit
improvement. composite is a noun, not a verb, but this function does
stuff, so we need a verb. Also I feel like compose_planes (i.e. the
original name) reflects better what it actually does.

>  		     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);
> @@ -177,8 +178,14 @@ static int composite(void **vaddr_out,
>  
>  	memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);
>  
> -	if (cursor_composer)
> -		compose_planes(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_planes(primary_composer,

Ofc that then clashes with compose_planes here, but this function only
composes a single plane. So the plural plane_s_ is kinda wrong, and we
could just call this function compose_plane. I think with that bikeshed
this reads a bit better. So please adjust that in patch 2 (keep the r-b)
and this here also lgtm.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> +			       crtc_state->active_planes[i]->composer,
> +			       *vaddr_out);
>  
>  	return 0;
>  }
> @@ -200,7 +207,7 @@ 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;
> @@ -224,11 +231,11 @@ 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;
> @@ -236,7 +243,7 @@ void vkms_composer_worker(struct work_struct *work)
>  	if (wb_pending)
>  		vaddr_out = crtc_state->active_writeback;
>  
> -	ret = composite(&vaddr_out, primary_composer, cursor_composer);
> +	ret = composite(&vaddr_out, primary_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..8be9eab41ea0 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,
> @@ -200,11 +200,19 @@ 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;
> -- 
> 2.30.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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