[1/3] drm: introduce share plane

Message ID	1469519194-23133-1-git-send-email-mark.yao@rock-chips.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <dri-devel-bounces@lists.freedesktop.org> From: Mark Yao <mark.yao@rock-chips.com> To: David Airlie <airlied@linux.ie>, Heiko Stuebner <heiko@sntech.de>, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] drm: introduce share plane Date: Tue, 26 Jul 2016 15:46:32 +0800 Message-Id: <1469519194-23133-1-git-send-email-mark.yao@rock-chips.com> Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" <dri-devel-bounces@lists.freedesktop.org>

yao mark July 26, 2016, 7:46 a.m. UTC

What is share plane:
Plane hardware only be used when the display scanout run into plane active
scanout, that means we can reuse the plane hardware resources on plane
non-active scanout.

     --------------------------------------------------
    |  scanout                                       |
    |         ------------------                     |
    |         | parent plane   |                     |
    |         | active scanout |                     |
    |         |                |   ----------------- |
    |         ------------------   | share plane 1 | |
    |  -----------------           |active scanout | |
    |  | share plane 0 |           |               | |
    |  |active scanout |           ----------------- |
    |  |               |                             |
    |  -----------------                             |
    --------------------------------------------------
One plane hardware can be reuse for multi-planes, we assume the first
plane is parent plane, other planes share the resource with first one.
    parent plane
        |---share plane 0
        |---share plane 1
        ...

Because resource share, There are some limit on share plane: one group
of share planes need use same zpos, can not overlap, etc.

We assume share plane is a universal plane with some limit flags.
people who use the share plane need know the limit, should call the ioctl
DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.

A group of share planes would has same shard id, so userspace can
group them, judge share plane's limit.

Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
---
 drivers/gpu/drm/drm_crtc.c  | 110 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_ioctl.c |   5 ++
 include/drm/drmP.h          |   5 ++
 include/drm/drm_crtc.h      |  14 ++++++
 include/uapi/drm/drm.h      |   7 +++
 5 files changed, 141 insertions(+)

Daniel Vetter July 26, 2016, 8:26 a.m. UTC | #1

On Tue, Jul 26, 2016 at 03:46:32PM +0800, Mark Yao wrote:
> What is share plane:
> Plane hardware only be used when the display scanout run into plane active
> scanout, that means we can reuse the plane hardware resources on plane
> non-active scanout.
> 
>      --------------------------------------------------
>     |  scanout                                       |
>     |         ------------------                     |
>     |         | parent plane   |                     |
>     |         | active scanout |                     |
>     |         |                |   ----------------- |
>     |         ------------------   | share plane 1 | |
>     |  -----------------           |active scanout | |
>     |  | share plane 0 |           |               | |
>     |  |active scanout |           ----------------- |
>     |  |               |                             |
>     |  -----------------                             |
>     --------------------------------------------------
> One plane hardware can be reuse for multi-planes, we assume the first
> plane is parent plane, other planes share the resource with first one.
>     parent plane
>         |---share plane 0
>         |---share plane 1
>         ...
> 
> Because resource share, There are some limit on share plane: one group
> of share planes need use same zpos, can not overlap, etc.
> 
> We assume share plane is a universal plane with some limit flags.
> people who use the share plane need know the limit, should call the ioctl
> DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
> 
> A group of share planes would has same shard id, so userspace can
> group them, judge share plane's limit.
> 
> Signed-off-by: Mark Yao <mark.yao@rock-chips.com>

This seems extremely hw specific, why exactly do we need to add a new
relationship on planes? What does this buy on _other_ drivers?

Imo this should be solved by virtualizing planes in the driver. Start out
by assigning planes, and if you can reuse one for sharing then do that,
otherwise allocate a new one. If there's not enough real planes, fail the
atomic_check.

This seems way to hw specific to be useful as a generic concept.
-Daniel

> ---
>  drivers/gpu/drm/drm_crtc.c  | 110 ++++++++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_ioctl.c |   5 ++
>  include/drm/drmP.h          |   5 ++
>  include/drm/drm_crtc.h      |  14 ++++++
>  include/uapi/drm/drm.h      |   7 +++
>  5 files changed, 141 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 9d3f80e..3a8257e 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -1426,6 +1426,96 @@ int drm_plane_init(struct drm_device *dev, struct drm_plane *plane,
>  EXPORT_SYMBOL(drm_plane_init);
>  
>  /**
> + * drm_share_plane_init - Initialize a share plane
> + * @dev: DRM device
> + * @plane: plane object to init
> + * @parent: this plane share some resources with parent plane.
> + * @possible_crtcs: bitmask of possible CRTCs
> + * @funcs: callbacks for the new plane
> + * @formats: array of supported formats (%DRM_FORMAT_*)
> + * @format_count: number of elements in @formats
> + * @type: type of plane (overlay, primary, cursor)
> + *
> + * With this API, the plane can share hardware resources with other planes.
> + *
> + *   --------------------------------------------------
> + *   |  scanout                                       |
> + *   |         ------------------                     |
> + *   |         |  parent plane  |                     |
> + *   |         | active scanout |                     |
> + *   |         |                |   ----------------- |
> + *   |         ------------------   | share plane 1 | |
> + *   |  -----------------           |active scanout | |
> + *   |  | share plane 0 |           |               | |
> + *   |  |active scanout |           ----------------- |
> + *   |  |               |                             |
> + *   |  -----------------                             |
> + *   --------------------------------------------------
> + *
> + *    parent plane
> + *        |---share plane 0
> + *        |---share plane 1
> + *        ...
> + *
> + * The plane hardware is used when the display scanout run into plane active
> + * scanout, that means we can reuse the plane hardware resources on plane
> + * non-active scanout.
> + *
> + * Because resource share, There are some limit on share plane: one group
> + * of share planes need use same zpos, can't not overlap, etc.
> + *
> + * Here assume share plane is a universal plane with some limit flags.
> + * people who use the share plane need know the limit, should call the ioctl
> + * DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
> + *
> + * Returns:
> + * Zero on success, error code on failure.
> + */
> +
> +int drm_share_plane_init(struct drm_device *dev, struct drm_plane *plane,
> +			 struct drm_plane *parent,
> +			 unsigned long possible_crtcs,
> +			 const struct drm_plane_funcs *funcs,
> +			 const uint32_t *formats, unsigned int format_count,
> +			 enum drm_plane_type type)
> +{
> +	struct drm_mode_config *config = &dev->mode_config;
> +	int ret;
> +	int share_id;
> +
> +	/*
> +	 * TODO: only verified on ATOMIC drm driver.
> +	 */
> +	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
> +		return -EINVAL;
> +
> +	ret = drm_universal_plane_init(dev, plane, possible_crtcs, funcs,
> +				       formats, format_count, type, NULL);
> +	if (ret)
> +		return ret;
> +
> +	if (parent) {
> +		/*
> +		 * Can't support more than two level plane share.
> +		 */
> +		WARN_ON(parent->parent);
> +		share_id = parent->base.id;
> +		plane->parent = parent;
> +
> +		config->num_share_plane++;
> +		if (plane->type == DRM_PLANE_TYPE_OVERLAY)
> +			config->num_share_overlay_plane++;
> +	} else {
> +		share_id = plane->base.id;
> +	}
> +
> +	drm_object_attach_property(&plane->base,
> +				   config->prop_share_id, share_id);
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_share_plane_init);
> +
> +/**
>   * drm_plane_cleanup - Clean up the core plane usage
>   * @plane: plane to cleanup
>   *
> @@ -1452,6 +1542,11 @@ void drm_plane_cleanup(struct drm_plane *plane)
>  	dev->mode_config.num_total_plane--;
>  	if (plane->type == DRM_PLANE_TYPE_OVERLAY)
>  		dev->mode_config.num_overlay_plane--;
> +	if (plane->parent) {
> +		dev->mode_config.num_share_plane--;
> +		if (plane->type == DRM_PLANE_TYPE_OVERLAY)
> +			dev->mode_config.num_share_overlay_plane--;
> +	}
>  	drm_modeset_unlock_all(dev);
>  
>  	WARN_ON(plane->state && !plane->funcs->atomic_destroy_state);
> @@ -1600,6 +1695,13 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
>  		return -ENOMEM;
>  	dev->mode_config.plane_type_property = prop;
>  
> +	prop = drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE,
> +					 "SHARE_ID", 0, UINT_MAX);
> +	if (!prop)
> +		return -ENOMEM;
> +
> +	dev->mode_config.prop_share_id = prop;
> +
>  	prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
>  			"SRC_X", 0, UINT_MAX);
>  	if (!prop)
> @@ -2431,6 +2533,12 @@ int drm_mode_getplane_res(struct drm_device *dev, void *data,
>  		num_planes = config->num_total_plane;
>  	else
>  		num_planes = config->num_overlay_plane;
> +	if (!file_priv->share_planes) {
> +		if (file_priv->universal_planes)
> +			num_planes -= config->num_share_plane;
> +		else
> +			num_planes -= config->num_share_overlay_plane;
> +	}
>  
>  	/*
>  	 * This ioctl is called twice, once to determine how much space is
> @@ -2449,6 +2557,8 @@ int drm_mode_getplane_res(struct drm_device *dev, void *data,
>  			if (plane->type != DRM_PLANE_TYPE_OVERLAY &&
>  			    !file_priv->universal_planes)
>  				continue;
> +			if (plane->parent && !file_priv->share_planes)
> +				continue;
>  
>  			if (put_user(plane->base.id, plane_ptr + copied))
>  				return -EFAULT;
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index 33af4a5..8b0120d 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -294,6 +294,11 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
>  			return -EINVAL;
>  		file_priv->universal_planes = req->value;
>  		break;
> +	case DRM_CLIENT_CAP_SHARE_PLANES:
> +		if (req->value > 1)
> +			return -EINVAL;
> +		file_priv->share_planes = req->value;
> +		break;
>  	case DRM_CLIENT_CAP_ATOMIC:
>  		if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
>  			return -EINVAL;
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index c2fe2cf..285d177 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -314,6 +314,11 @@ struct drm_file {
>  	/* true if client understands atomic properties */
>  	unsigned atomic:1;
>  	/*
> +	 * true if client understands share planes and
> +	 * hardware support share planes.
> +	 */
> +	unsigned share_planes:1;
> +	/*
>  	 * This client is the creator of @master.
>  	 * Protected by struct drm_device::master_mutex.
>  	 */
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 9e6ab4a..a3fe9b0 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -1660,6 +1660,7 @@ enum drm_plane_type {
>  /**
>   * struct drm_plane - central DRM plane control structure
>   * @dev: DRM device this plane belongs to
> + * @parent: this plane share some resources with parent plane.
>   * @head: for list management
>   * @name: human readable name, can be overwritten by the driver
>   * @base: base mode object
> @@ -1679,6 +1680,7 @@ enum drm_plane_type {
>   */
>  struct drm_plane {
>  	struct drm_device *dev;
> +	struct drm_plane *parent;
>  	struct list_head head;
>  
>  	char *name;
> @@ -2408,6 +2410,8 @@ struct drm_mode_config {
>  	 */
>  	int num_overlay_plane;
>  	int num_total_plane;
> +	int num_share_plane;
> +	int num_share_overlay_plane;
>  	struct list_head plane_list;
>  
>  	int num_crtc;
> @@ -2428,6 +2432,9 @@ struct drm_mode_config {
>  
>  	struct mutex blob_lock;
>  
> +	/* pointers to share properties */
> +	struct drm_property *prop_share_id;
> +
>  	/* pointers to standard properties */
>  	struct list_head property_blob_list;
>  	struct drm_property *edid_property;
> @@ -2636,6 +2643,13 @@ extern int drm_plane_init(struct drm_device *dev,
>  			  const struct drm_plane_funcs *funcs,
>  			  const uint32_t *formats, unsigned int format_count,
>  			  bool is_primary);
> +extern int drm_share_plane_init(struct drm_device *dev, struct drm_plane *plane,
> +				struct drm_plane *parent,
> +				unsigned long possible_crtcs,
> +				const struct drm_plane_funcs *funcs,
> +				const uint32_t *formats,
> +				unsigned int format_count,
> +				enum drm_plane_type type);
>  extern void drm_plane_cleanup(struct drm_plane *plane);
>  
>  /**
> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index 452675f..01979a4 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -677,6 +677,13 @@ struct drm_get_cap {
>   */
>  #define DRM_CLIENT_CAP_ATOMIC	3
>  
> +/**
> + * DRM_CLIENT_CAP_SHARE_PLANES
> + *
> + * If set to 1, the DRM core will expose share planes to userspace.
> + */
> +#define DRM_CLIENT_CAP_SHARE_PLANES	4
> +
>  /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
>  struct drm_set_client_cap {
>  	__u64 capability;
> -- 
> 1.9.1
> 
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

yao mark July 26, 2016, 9:51 a.m. UTC | #2

On 2016年07月26日 16:26, Daniel Vetter wrote:
> On Tue, Jul 26, 2016 at 03:46:32PM +0800, Mark Yao wrote:
>> >What is share plane:
>> >Plane hardware only be used when the display scanout run into plane active
>> >scanout, that means we can reuse the plane hardware resources on plane
>> >non-active scanout.
>> >
>> >      --------------------------------------------------
>> >     |  scanout                                       |
>> >     |         ------------------                     |
>> >     |         | parent plane   |                     |
>> >     |         | active scanout |                     |
>> >     |         |                |   ----------------- |
>> >     |         ------------------   | share plane 1 | |
>> >     |  -----------------           |active scanout | |
>> >     |  | share plane 0 |           |               | |
>> >     |  |active scanout |           ----------------- |
>> >     |  |               |                             |
>> >     |  -----------------                             |
>> >     --------------------------------------------------
>> >One plane hardware can be reuse for multi-planes, we assume the first
>> >plane is parent plane, other planes share the resource with first one.
>> >     parent plane
>> >         |---share plane 0
>> >         |---share plane 1
>> >         ...
>> >
>> >Because resource share, There are some limit on share plane: one group
>> >of share planes need use same zpos, can not overlap, etc.
>> >
>> >We assume share plane is a universal plane with some limit flags.
>> >people who use the share plane need know the limit, should call the ioctl
>> >DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
>> >
>> >A group of share planes would has same shard id, so userspace can
>> >group them, judge share plane's limit.
>> >
>> >Signed-off-by: Mark Yao<mark.yao@rock-chips.com>
> This seems extremely hw specific, why exactly do we need to add a new
> relationship on planes? What does this buy on_other_  drivers?
Yes, now it's plane hardware specific, maybe others have same design, 
because this design
would save hardware resource to support multi-planes.

> Imo this should be solved by virtualizing planes in the driver. Start out
> by assigning planes, and if you can reuse one for sharing then do that,
> otherwise allocate a new one. If there's not enough real planes, fail the
> atomic_check.
I think that is too complex, trying with atomic_check I think it's not a 
good idea, userspace try planes every commit would be a heavy work.

Userspace need  know all planes relationship, group them, some display 
windows can put together, some can't,
too many permutation and combination, I think can't just commit with try.

example:
userspace:
windows 1: pos(0, 0)  size(1024, 100)
windows 2: pos(0, 50) size(400, 500)
windows 3: pos(0, 200) size(800, 300)

drm plane resources:
plane 0 and plane 1 is a group of share planes
plane 2 is common plane.

if userspace know the relationship, then they can assign windows 1 and 
window 3 to plane0 and plane 1. that would be success.
but if they don't know, assign window 1/2 to plane 0/1, failed, assign 
window 2/3 to plane 0/1, failed. mostly would get failed.

>
> This seems way to hw specific to be useful as a generic concept.

We want to change the drm_mode_getplane_res behavior, if userspace call 
DRM_CLIENT_CAP_SHARE_PLANES, that means userspace know hardware limit,
then we return full planes support to userspace, if don't, just make a 
group of share planes as one plane.
this work is on generic place.

> -Daniel
>
>

yao mark July 28, 2016, 3:01 a.m. UTC | #3

Any ideas for the share planes?

This function is important for our series of vop full design.
     The series of vop is:
     IP version    chipname
     3.1           rk3288
     3.2           rk3368
     3.4           rk3366
     3.5           rk3399 big
     3.6           rk3399 lit
     3.7           rk322x

example on rk3288:  if not support share plane, each vop only support 
four planes, but if support this function, each vop can support ten planes.

On 2016年07月26日 17:51, Mark yao wrote:
> On 2016年07月26日 16:26, Daniel Vetter wrote:
>> On Tue, Jul 26, 2016 at 03:46:32PM +0800, Mark Yao wrote:
>>> >What is share plane:
>>> >Plane hardware only be used when the display scanout run into plane 
>>> active
>>> >scanout, that means we can reuse the plane hardware resources on plane
>>> >non-active scanout.
>>> >
>>> >      --------------------------------------------------
>>> >     |  scanout                                       |
>>> >     |         ------------------                     |
>>> >     |         | parent plane   |                     |
>>> >     |         | active scanout |                     |
>>> >     |         |                |   ----------------- |
>>> >     |         ------------------   | share plane 1 | |
>>> >     |  -----------------           |active scanout | |
>>> >     |  | share plane 0 |           |               | |
>>> >     |  |active scanout |           ----------------- |
>>> >     |  |               |                             |
>>> >     |  -----------------                             |
>>> >     --------------------------------------------------
>>> >One plane hardware can be reuse for multi-planes, we assume the first
>>> >plane is parent plane, other planes share the resource with first one.
>>> >     parent plane
>>> >         |---share plane 0
>>> >         |---share plane 1
>>> >         ...
>>> >
>>> >Because resource share, There are some limit on share plane: one group
>>> >of share planes need use same zpos, can not overlap, etc.
>>> >
>>> >We assume share plane is a universal plane with some limit flags.
>>> >people who use the share plane need know the limit, should call the 
>>> ioctl
>>> >DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
>>> >
>>> >A group of share planes would has same shard id, so userspace can
>>> >group them, judge share plane's limit.
>>> >
>>> >Signed-off-by: Mark Yao<mark.yao@rock-chips.com>
>> This seems extremely hw specific, why exactly do we need to add a new
>> relationship on planes? What does this buy on_other_  drivers?
> Yes, now it's plane hardware specific, maybe others have same design, 
> because this design
> would save hardware resource to support multi-planes.
>
>> Imo this should be solved by virtualizing planes in the driver. Start 
>> out
>> by assigning planes, and if you can reuse one for sharing then do that,
>> otherwise allocate a new one. If there's not enough real planes, fail 
>> the
>> atomic_check.
> I think that is too complex, trying with atomic_check I think it's not 
> a good idea, userspace try planes every commit would be a heavy work.
>
> Userspace need  know all planes relationship, group them, some display 
> windows can put together, some can't,
> too many permutation and combination, I think can't just commit with try.
>
> example:
> userspace:
> windows 1: pos(0, 0)  size(1024, 100)
> windows 2: pos(0, 50) size(400, 500)
> windows 3: pos(0, 200) size(800, 300)
>
> drm plane resources:
> plane 0 and plane 1 is a group of share planes
> plane 2 is common plane.
>
> if userspace know the relationship, then they can assign windows 1 and 
> window 3 to plane0 and plane 1. that would be success.
> but if they don't know, assign window 1/2 to plane 0/1, failed, assign 
> window 2/3 to plane 0/1, failed. mostly would get failed.
>
>>
>> This seems way to hw specific to be useful as a generic concept.
>
> We want to change the drm_mode_getplane_res behavior, if userspace 
> call DRM_CLIENT_CAP_SHARE_PLANES, that means userspace know hardware 
> limit,
> then we return full planes support to userspace, if don't, just make a 
> group of share planes as one plane.
> this work is on generic place.
>
>> -Daniel
>>
>>
>

Daniel Vetter July 28, 2016, 8:03 a.m. UTC | #4

On Thu, Jul 28, 2016 at 11:01:04AM +0800, Mark yao wrote:
> Any ideas for the share planes?
> 
> This function is important for our series of vop full design.
>     The series of vop is:
>     IP version    chipname
>     3.1           rk3288
>     3.2           rk3368
>     3.4           rk3366
>     3.5           rk3399 big
>     3.6           rk3399 lit
>     3.7           rk322x
> 
> example on rk3288:  if not support share plane, each vop only support four
> planes, but if support this function, each vop can support ten planes.

Like I said, register 10 planes in the kernel driver, figure out a good
way to actually allocate them to hw resources. We have a similar issue on
skl/bxt in the i915 driver where there's only a limited amount of
scalers, and we need to dynamically allocate them to drm_plane. Here you
have fancy amount of scanout engines which you need to dynamically
allocate.

> On 2016年07月26日 17:51, Mark yao wrote:
> > On 2016年07月26日 16:26, Daniel Vetter wrote:
> > > On Tue, Jul 26, 2016 at 03:46:32PM +0800, Mark Yao wrote:
> > > > >What is share plane:
> > > > >Plane hardware only be used when the display scanout run into
> > > > plane active
> > > > >scanout, that means we can reuse the plane hardware resources on plane
> > > > >non-active scanout.
> > > > >
> > > > >      --------------------------------------------------
> > > > >     |  scanout                                       |
> > > > >     |         ------------------                     |
> > > > >     |         | parent plane   |                     |
> > > > >     |         | active scanout |                     |
> > > > >     |         |                |   ----------------- |
> > > > >     |         ------------------   | share plane 1 | |
> > > > >     |  -----------------           |active scanout | |
> > > > >     |  | share plane 0 |           |               | |
> > > > >     |  |active scanout |           ----------------- |
> > > > >     |  |               |                             |
> > > > >     |  -----------------                             |
> > > > >     --------------------------------------------------
> > > > >One plane hardware can be reuse for multi-planes, we assume the first
> > > > >plane is parent plane, other planes share the resource with first one.
> > > > >     parent plane
> > > > >         |---share plane 0
> > > > >         |---share plane 1
> > > > >         ...
> > > > >
> > > > >Because resource share, There are some limit on share plane: one group
> > > > >of share planes need use same zpos, can not overlap, etc.
> > > > >
> > > > >We assume share plane is a universal plane with some limit flags.
> > > > >people who use the share plane need know the limit, should call
> > > > the ioctl
> > > > >DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
> > > > >
> > > > >A group of share planes would has same shard id, so userspace can
> > > > >group them, judge share plane's limit.
> > > > >
> > > > >Signed-off-by: Mark Yao<mark.yao@rock-chips.com>
> > > This seems extremely hw specific, why exactly do we need to add a new
> > > relationship on planes? What does this buy on_other_  drivers?
> > Yes, now it's plane hardware specific, maybe others have same design,
> > because this design
> > would save hardware resource to support multi-planes.
> > 
> > > Imo this should be solved by virtualizing planes in the driver.
> > > Start out
> > > by assigning planes, and if you can reuse one for sharing then do that,
> > > otherwise allocate a new one. If there's not enough real planes,
> > > fail the
> > > atomic_check.
> > I think that is too complex, trying with atomic_check I think it's not a
> > good idea, userspace try planes every commit would be a heavy work.
> > 
> > Userspace need  know all planes relationship, group them, some display
> > windows can put together, some can't,
> > too many permutation and combination, I think can't just commit with try.
> > 
> > example:
> > userspace:
> > windows 1: pos(0, 0)  size(1024, 100)
> > windows 2: pos(0, 50) size(400, 500)
> > windows 3: pos(0, 200) size(800, 300)
> > 
> > drm plane resources:
> > plane 0 and plane 1 is a group of share planes
> > plane 2 is common plane.
> > 
> > if userspace know the relationship, then they can assign windows 1 and
> > window 3 to plane0 and plane 1. that would be success.
> > but if they don't know, assign window 1/2 to plane 0/1, failed, assign
> > window 2/3 to plane 0/1, failed. mostly would get failed.

You can still do this with the design I describe. The only difference is
that you allow generic userspace to make optimal use of your planes, too.

> > > This seems way to hw specific to be useful as a generic concept.
> > 
> > We want to change the drm_mode_getplane_res behavior, if userspace call
> > DRM_CLIENT_CAP_SHARE_PLANES, that means userspace know hardware limit,
> > then we return full planes support to userspace, if don't, just make a
> > group of share planes as one plane.
> > this work is on generic place.

So ... do you have patches for all the generic kms userspace that's out
there? Are those reviewed and ready for merging?

Adding new userspace abi is much, much, much harder than sovling this in
the vop driver. I'm working on some documentation to make this all clear
(since many arm folks seem unaware of the uapi rules we have in the drm
subsystem). But really, you're trying the much harder route with this
patch.
-Daniel

yao mark July 28, 2016, 9:28 a.m. UTC | #5

On 2016年07月28日 16:03, Daniel Vetter wrote:
> On Thu, Jul 28, 2016 at 11:01:04AM +0800, Mark yao wrote:
>> Any ideas for the share planes?
>>
>> This function is important for our series of vop full design.
>>      The series of vop is:
>>      IP version    chipname
>>      3.1           rk3288
>>      3.2           rk3368
>>      3.4           rk3366
>>      3.5           rk3399 big
>>      3.6           rk3399 lit
>>      3.7           rk322x
>>
>> example on rk3288:  if not support share plane, each vop only support four
>> planes, but if support this function, each vop can support ten planes.
> Like I said, register 10 planes in the kernel driver, figure out a good
> way to actually allocate them to hw resources. We have a similar issue on
> skl/bxt in the i915 driver where there's only a limited amount of
> scalers, and we need to dynamically allocate them to drm_plane. Here you
> have fancy amount of scanout engines which you need to dynamically
> allocate.
>
>> On 2016年07月26日 17:51, Mark yao wrote:
>>> On 2016年07月26日 16:26, Daniel Vetter wrote:
>>>> On Tue, Jul 26, 2016 at 03:46:32PM +0800, Mark Yao wrote:
>>>>>> What is share plane:
>>>>>> Plane hardware only be used when the display scanout run into
>>>>> plane active
>>>>>> scanout, that means we can reuse the plane hardware resources on plane
>>>>>> non-active scanout.
>>>>>>
>>>>>>       --------------------------------------------------
>>>>>>      |  scanout                                       |
>>>>>>      |         ------------------                     |
>>>>>>      |         | parent plane   |                     |
>>>>>>      |         | active scanout |                     |
>>>>>>      |         |                |   ----------------- |
>>>>>>      |         ------------------   | share plane 1 | |
>>>>>>      |  -----------------           |active scanout | |
>>>>>>      |  | share plane 0 |           |               | |
>>>>>>      |  |active scanout |           ----------------- |
>>>>>>      |  |               |                             |
>>>>>>      |  -----------------                             |
>>>>>>      --------------------------------------------------
>>>>>> One plane hardware can be reuse for multi-planes, we assume the first
>>>>>> plane is parent plane, other planes share the resource with first one.
>>>>>>      parent plane
>>>>>>          |---share plane 0
>>>>>>          |---share plane 1
>>>>>>          ...
>>>>>>
>>>>>> Because resource share, There are some limit on share plane: one group
>>>>>> of share planes need use same zpos, can not overlap, etc.
>>>>>>
>>>>>> We assume share plane is a universal plane with some limit flags.
>>>>>> people who use the share plane need know the limit, should call
>>>>> the ioctl
>>>>>> DRM_CLIENT_CAP_SHARE_PLANES, and judge the planes limit before use it.
>>>>>>
>>>>>> A group of share planes would has same shard id, so userspace can
>>>>>> group them, judge share plane's limit.
>>>>>>
>>>>>> Signed-off-by: Mark Yao<mark.yao@rock-chips.com>
>>>> This seems extremely hw specific, why exactly do we need to add a new
>>>> relationship on planes? What does this buy on_other_  drivers?
>>> Yes, now it's plane hardware specific, maybe others have same design,
>>> because this design
>>> would save hardware resource to support multi-planes.
>>>
>>>> Imo this should be solved by virtualizing planes in the driver.
>>>> Start out
>>>> by assigning planes, and if you can reuse one for sharing then do that,
>>>> otherwise allocate a new one. If there's not enough real planes,
>>>> fail the
>>>> atomic_check.
>>> I think that is too complex, trying with atomic_check I think it's not a
>>> good idea, userspace try planes every commit would be a heavy work.
>>>
>>> Userspace need  know all planes relationship, group them, some display
>>> windows can put together, some can't,
>>> too many permutation and combination, I think can't just commit with try.
>>>
>>> example:
>>> userspace:
>>> windows 1: pos(0, 0)  size(1024, 100)
>>> windows 2: pos(0, 50) size(400, 500)
>>> windows 3: pos(0, 200) size(800, 300)
>>>
>>> drm plane resources:
>>> plane 0 and plane 1 is a group of share planes
>>> plane 2 is common plane.
>>>
>>> if userspace know the relationship, then they can assign windows 1 and
>>> window 3 to plane0 and plane 1. that would be success.
>>> but if they don't know, assign window 1/2 to plane 0/1, failed, assign
>>> window 2/3 to plane 0/1, failed. mostly would get failed.
> You can still do this with the design I describe. The only difference is
> that you allow generic userspace to make optimal use of your planes, too.
>
>>>> This seems way to hw specific to be useful as a generic concept.
>>> We want to change the drm_mode_getplane_res behavior, if userspace call
>>> DRM_CLIENT_CAP_SHARE_PLANES, that means userspace know hardware limit,
>>> then we return full planes support to userspace, if don't, just make a
>>> group of share planes as one plane.
>>> this work is on generic place.
> So ... do you have patches for all the generic kms userspace that's out
> there? Are those reviewed and ready for merging?
No, we have no other patches send to generic kms userspace upstream.

We use it on our internal userspace application now.

on our userspace application:
1, directly call drmSetClientCap(fd(), DRM_CLIENT_CAP_SHARE_PLANES, 1);
2, get planes with drmModeGetResources(fd());
3, get plane share id with drmModeObjectGetProperties,
4, group the planes with share id, if two plane use same "share id", 
that means these plane is on the same group
5, judge the plane's limit when doing plane commit.

on userspace only add a new ioctl macro DRM_CLIENT_CAP_SHARE_PLANES.

> Adding new userspace abi is much, much, much harder than sovling this in
> the vop driver. I'm working on some documentation to make this all clear
> (since many arm folks seem unaware of the uapi rules we have in the drm
> subsystem). But really, you're trying the much harder route with this
> patch.
Hmmm, So sad, you are right, change the generic api is a harder work.

Ok, I will try your advice.

Thanks.

> -Daniel

[1/3] drm: introduce share plane

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