Re: [PATCH 1/4] drm: add generic zpos property

Hi Benjamin,

Thank you for the patch.

I would have started working on this next week, thanks for beating me to it :-)

On Wednesday 11 May 2016 12:25:05 Benjamin Gaignard wrote:

This patch adds support for generic plane's zpos property property with well-defined semantics:

• added zpos properties to plane and plane state structures
• added helpers for normalizing zpos properties of given set of planes
• well defined semantics: planes are sorted by zpos values and then plane id value if zpos equals

Normalized zpos values are calculated automatically when generic muttable zpos property has been initialized. Drivers can simply use plane_state->normalized_zpos in their atomic_check and/or plane_update callbacks without any additional calls to DRM core.

Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com

Compare to Marek's original patch zpos property is now specific to each plane and no more to the core. Normalize function take care of the range of per plane defined range before set normalized_zpos.

Signed-off-by: Benjamin Gaignard benjamin.gaignard@linaro.org

Cc: Inki Dae inki.dae@samsung.com Cc: Daniel Vetter daniel@ffwll.ch Cc: Ville Syrjala ville.syrjala@linux.intel.com Cc: Joonyoung Shim jy0922.shim@samsung.com Cc: Seung-Woo Kim sw0312.kim@samsung.com Cc: Andrzej Hajda a.hajda@samsung.com Cc: Krzysztof Kozlowski k.kozlowski@samsung.com Cc: Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com Cc: Tobias Jakobi tjakobi@math.uni-bielefeld.de Cc: Gustavo Padovan gustavo@padovan.org Cc: vincent.abriou@st.com Cc: fabien.dessenne@st.com Cc: Laurent Pinchart laurent.pinchart@ideasonboard.com

---

Documentation/DocBook/gpu.tmpl | 10 ++ drivers/gpu/drm/Makefile | 2 +- drivers/gpu/drm/drm_atomic_helper.c | 6 + drivers/gpu/drm/drm_blend.c | 284 +++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_crtc_internal.h | 3 + include/drm/drm_crtc.h | 25 ++++ 6 files changed, 329 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/drm_blend.c

diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl index 9dd48f7..0df6abb 100644 --- a/Documentation/DocBook/gpu.tmpl +++ b/Documentation/DocBook/gpu.tmpl @@ -2151,6 +2151,16 @@ void intel_crt_init(struct drm_device *dev) the underlying hardware).</td>

</tr> <tr> + <td valign="top" > "zpos" </td> + <td valign="top" >RANGE</td> + <td valign="top" >Min= driver dependent, Max= driver dependent</td> + <td valign="top" >Plane</td> + <td valign="top" >Plane's 'z' position during blending operation (0 for background, highest for frontmost). + If two planes assigned to same CRTC have equal zpos values, the plane with higher plane + id is treated as closer to front. Can be IMMUTABLE if driver doesn't support changing + planes' order. Exact value range is driver dependent.</td> + </tr> + <tr> <td rowspan="20" valign="top" >i915</td> <td rowspan="2" valign="top" >Generic</td> <td valign="top" >"Broadcast RGB"</td> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 2bd3e5a..df88253 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -2,7 +2,7 @@ # Makefile for the drm device driver. This driver provides support for the # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.

-drm-y := drm_auth.o drm_bufs.o drm_cache.o \ +drm-y := drm_auth.o drm_bufs.o drm_blend.o drm_cache.o \ drm_context.o drm_dma.o \ drm_fops.o drm_gem.o drm_ioctl.o drm_irq.o \ drm_lock.o drm_memory.o drm_drv.o drm_vm.o \ diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 997fd21..f10652f 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -32,6 +32,8 @@ #include <drm/drm_atomic_helper.h> #include <linux/fence.h>

+#include "drm_crtc_internal.h"

drm_atomic_helper_normalize_zpos() is declared in <drm/drm_crtc.h>, why do you need to include drm_crtc_internal.h ?

/**

• DOC: overview

@@ -587,6 +589,10 @@ drm_atomic_helper_check_planes(struct drm_device *dev, struct drm_plane_state *plane_state; int i, ret = 0;

• ret = drm_atomic_helper_normalize_zpos(dev, state);
• if (ret)

• return ret;
  

• for_each_plane_in_state(state, plane, plane_state, i) { const struct drm_plane_helper_funcs *funcs;

diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c new file mode 100644 index 0000000..7017715 --- /dev/null +++ b/drivers/gpu/drm/drm_blend.c @@ -0,0 +1,284 @@

[snip]

+#include <linux/slab.h> +#include <linux/sort.h> +#include <linux/export.h> +#include <drm/drmP.h> +#include <drm/drm_crtc.h> +#include <drm/drm_atomic.h>

Nitpicking, could you please keep header files alphabetically sorted ? It helps locating and avoiding duplicates.

+#include "drm_internal.h"

+#define MAX(a, b) (((a) > (b)) ? (a) : (b))

linux/kernel.h has max and max_t, is there really a need for a new macro ?

+/**

• • drm_plane_atomic_set_zpos_property - set plane zpos property
• • @plane: drm plane
• • @state: drm plane state
• • @property: must be the zpos property associated to the plane
• • @val: zpos value to be set
• • Returns:
• • Zero on success, negative errno on failure.
• */

+int drm_plane_atomic_set_zpos_property(struct drm_plane *plane,

• 		       struct drm_plane_state *state,
  

• 		       struct drm_property *property,
  

• 		       uint64_t val)
  

+{

• struct drm_mode_object *obj = &plane->base;
• int i;
• for (i = 0; i < obj->properties->count; i++) {

• if (obj->properties->properties[i] == property) {
  

• 	state->zpos = val;
  

• 	return 0;
  

• }
  

• }
• return -EINVAL;

+} +EXPORT_SYMBOL(drm_plane_atomic_set_zpos_property);

Why do you need this function instead of adding zpos support to drm_atomic_plane_set_property() ? Same question for the get handler.

+/**

• • drm_plane_atomic_get_zpos_property - set plane zpos property
• • @plane: drm plane
• • @state: drm plane state
• • @property: must be the zpos property associated to the plane
• • @val: zpos value to be retrieve
• • Returns:
• • Zero on success, negative errno on failure.
• */

+int drm_plane_atomic_get_zpos_property(struct drm_plane *plane,

• 		       const struct drm_plane_state *state,
  

• 		       struct drm_property *property,
  

• 		       uint64_t *val)
  

+{

• struct drm_mode_object *obj = &plane->base;
• int i;
• for (i = 0; i < obj->properties->count; i++) {

• if (obj->properties->properties[i] == property) {
  

• 	*val = state->zpos;
  

• 	return 0;
  

• }
  

• }
• return -EINVAL;

+} +EXPORT_SYMBOL(drm_plane_atomic_get_zpos_property);

+/**

• • drm_plane_create_zpos_property - create mutable zpos property
• • @plane: drm plane
• • @min: minimal possible value of zpos property
• • @max: maximal possible value of zpos property
• • This function initializes generic mutable zpos property and enables

support

• • for it in drm core. Drivers can then attach this property to planes to

enable

• • support for configurable planes arrangement during blending operation.
• • Once mutable zpos property has been enabled, the DRM core will

automatically

• • calculate drm_plane_state->normalized_zpos values. Usually min should be

set

• • to 0 and max to maximal number of planes for given crtc - 1.
• • If zpos of some planes cannot be changed (like fixed background or
• • cursor/topmost planes), driver should adjust min/max values and assign

those

• • planes immutable zpos property with lower or higher values (for more
• • information, see drm_mode_create_zpos_immutable_property() function). In

such

• • case driver should also assign proper initial zpos values for all planes

in

• • its plane_reset() callback, so the planes will be always sorted

properly.

• • Returns:
• • Zero on success, negative errno on failure.
• */

+int drm_plane_create_zpos_property(struct drm_plane *plane,

• 		   unsigned int min, unsigned int max)
  

+{

• struct drm_property *prop;
• prop = drm_property_create_range(plane->dev, 0, "zpos", min, max);
• if (!prop)

• return -ENOMEM;
  

You should cache prop (in drm_mode_config) instead of recreating it for each plane, like done for the other properties. Same in the next function.

• drm_object_attach_property(&plane->base, prop, min);
• return 0;

+} +EXPORT_SYMBOL(drm_plane_create_zpos_property);

+/**

• • drm_plane_create_zpos_immutable_property - create immuttable zpos

property

• • @plane: drm plane
• • @min: minimal possible value of zpos property
• • @max: maximal possible value of zpos property
• • This function initializes generic immutable zpos property and enables
• • support for it in drm core. Using this property driver lets userspace
• • to get the arrangement of the planes for blending operation and notifies
• • it that the hardware (or driver) doesn't support changing of the

planes'

• • order.
• • Returns:
• • Zero on success, negative errno on failure.
• */

+int drm_plane_create_zpos_immutable_property(struct drm_plane *plane,

• 			     unsigned int min, unsigned int max)
  

+{

• struct drm_property *prop;
• prop = drm_property_create_range(plane->dev, DRM_MODE_PROP_IMMUTABLE,

• 			 "zpos", min, max);
  

Can two properties exist with the same name but different flags (immutable and mutable) ? Or with different min/max values ? I don't expect min/max to be different for every plane, so maybe a function that creates the zpos property once with min/max values and a second one that attaches the property to planes would be a better API.

• if (!prop)

• return -ENOMEM;
  

• drm_object_attach_property(&plane->base, prop, min);
• return 0;

+} +EXPORT_SYMBOL(drm_plane_create_zpos_immutable_property);

+static int drm_atomic_state_zpos_cmp(const void *a, const void *b) +{

• const struct drm_plane_state *sa = *(struct drm_plane_state **)a;
• const struct drm_plane_state *sb = *(struct drm_plane_state **)b;
• int zpos_a = (sa->zpos << 16) + sa->plane->base.id;
• int zpos_b = (sb->zpos << 16) + sb->plane->base.id;
• return zpos_a - zpos_b;

Instead of playing tricks with the ids that will create a dependency on the plane id value range, how about

if (sa->zpos != sb->zpos) return sa->zpos - sb->zpos; else return sa->plane->base.id - sb->plane->base.id;

+}

+/**

• • drm_atomic_helper_crtc_normalize_zpos - calculate normalized zpos values
• • @crtc: crtc with planes, which have to be considered for normalization
• • @crtc_state: new atomic state to apply
• • This function checks new states of all planes assigned to given crtc and
• • calculates normalized zpos value for them. Planes are compared first by

their

• • zpos values, then by plane id (if zpos equals). Plane with lowest zpos

value

• • is at the bottom. The plane_state->normalized_zpos is then filled with

unique

• • values from 0 to number of active planes in crtc minus one.
• • RETURNS
• • Zero for success or -errno
• */

+int drm_atomic_helper_crtc_normalize_zpos(struct drm_crtc *crtc,

• 			  struct drm_crtc_state *crtc_state)
  

+{

• struct drm_atomic_state *state = crtc_state->state;
• struct drm_device *dev = crtc->dev;
• int total_planes = dev->mode_config.num_total_plane;
• struct drm_plane_state **states;
• struct drm_plane *plane;
• int i, zpos, n = 0;
• int ret = 0;
• DRM_DEBUG_ATOMIC("[CRTC:%d:%s] calculating normalized zpos values\n",

• 	 crtc->base.id, crtc->name);
  

• states = kmalloc(total_planes * sizeof(*states), GFP_KERNEL);
• if (!states)

• return -ENOMEM;
  

• /*

• * Normalization process might create new states for planes which
  

• * normalized_zpos has to be recalculated.
  

• */
  

• drm_for_each_plane_mask(plane, dev, crtc_state->plane_mask) {

• struct drm_plane_state *plane_state =
  

• 	drm_atomic_get_plane_state(state, plane);
  

• if (IS_ERR(plane_state)) {
  

• 	ret = PTR_ERR(plane_state);
  

• 	goto fail;
  

• }
  

• states[n++] = plane_state;
  

• DRM_DEBUG_ATOMIC("[PLANE:%d:%s] processing zpos value %d\n",
  

• 		 plane->base.id, plane->name,
  

• 		 plane_state->zpos);
  

• }
• sort(states, n, sizeof(*states), drm_atomic_state_zpos_cmp, NULL);
• for (i = 0, zpos = 0; i < n; i++, zpos++) {

• plane = states[i]->plane;
  

• zpos = MAX(zpos, states[i]->zpos);
  

• states[i]->normalized_zpos = zpos;
  

Can't you just use i instead of MAX(zpos, states[i]->zpos) ?

• DRM_DEBUG_ATOMIC("[PLANE:%d:%s] normalized zpos value %d\n",
  

• 		 plane->base.id, plane->name, zpos);
  

• }
• crtc_state->zpos_changed = true;

+fail:

We reach the label in the normal code path too, I would thus call it done or exit instead of fail.

• kfree(states);
• return ret;

+} +EXPORT_SYMBOL(drm_atomic_helper_crtc_normalize_zpos);

+/**

• • drm_atomic_helper_normalize_zpos - calculate normalized zpos values for

all

• • 		      crtcs
    

• • @dev: DRM device
• • @state: atomic state of DRM device
• • This function calculates normalized zpos value for all modified planes

in

• • the provided atomic state of DRM device. For more information, see
• • drm_atomic_helper_crtc_normalize_zpos() function.
• • RETURNS
• • Zero for success or -errno
• */

+int drm_atomic_helper_normalize_zpos(struct drm_device *dev,

• 		     struct drm_atomic_state *state)
  

+{

• struct drm_crtc *crtc;
• struct drm_crtc_state *crtc_state;
• struct drm_plane *plane;
• struct drm_plane_state *plane_state;
• int i, ret = 0;
• for_each_plane_in_state(state, plane, plane_state, i) {

• crtc = plane_state->crtc;
  

• if (!crtc)
  

• 	continue;
  

• if (plane->state->zpos != plane_state->zpos) {
  

• 	crtc_state =
  

• 		drm_atomic_get_existing_crtc_state(state, crtc);
  

• 	crtc_state->zpos_changed = true;
  

• }
  

• }
• for_each_crtc_in_state(state, crtc, crtc_state, i) {

• if (crtc_state->plane_mask != crtc->state->plane_mask ||
  

•     crtc_state->zpos_changed) {
  

• 	ret = drm_atomic_helper_crtc_normalize_zpos(crtc,
  

• 						    crtc_state);
  

• 	if (ret)
  

• 		return ret;
  

• }
  

• }
• return 0;

+} +EXPORT_SYMBOL(drm_atomic_helper_normalize_zpos); diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h index a78c138..37d9068 100644 --- a/drivers/gpu/drm/drm_crtc_internal.h +++ b/drivers/gpu/drm/drm_crtc_internal.h @@ -42,3 +42,6 @@ int drm_atomic_get_property(struct drm_mode_object *obj, int drm_mode_atomic_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv);

+/* drm_blend.c */ +int drm_atomic_helper_normalize_zpos(struct drm_device *dev,

• 		     struct drm_atomic_state *state);
  

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index d1559cd..a34bc29 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -305,6 +305,7 @@ struct drm_plane_helper_funcs;

• @mode_changed: crtc_state->mode or crtc_state->enable has been changed
• @active_changed: crtc_state->active has been toggled.
• @connectors_changed: connectors to this crtc have been updated

• • @zpos_changed: zpos values of planes on this crtc have been updated
  • @color_mgmt_changed: color management properties have changed (degamma

or * gamma LUT or CSC matrix)

• @plane_mask: bitmask of (1 << drm_plane_index(plane)) of attached planes

@@ -340,6 +341,7 @@ struct drm_crtc_state { bool mode_changed : 1; bool active_changed : 1; bool connectors_changed : 1;

• bool zpos_changed : 1; bool color_mgmt_changed : 1;

  /* attached planes bitmask:

@@ -1263,6 +1265,9 @@ struct drm_connector {

• plane (in 16.16)
• @src_w: width of visible portion of plane (in 16.16)
• @src_h: height of visible portion of plane (in 16.16)

• • @zpos: priority of the given plane on crtc (optional)
• • @normalized_zpos: normalized value of zpos: unique, range from 0 to N

• • for given crtc
    

If N is the number of active planes that would be 0 to N-1. If N is the number of active planes minus one then this is correct :-)

• @state: backpointer to global drm_atomic_state

*/ struct drm_plane_state { @@ -1283,6 +1288,10 @@ struct drm_plane_state { /* Plane rotation */ unsigned int rotation;

• /* Plane zpos */
• unsigned int zpos;
• unsigned int normalized_zpos;
• struct drm_atomic_state *state;

};

@@ -2554,6 +2563,22 @@ extern struct drm_property *drm_mode_create_rotation_property(struct drm_device extern unsigned int drm_rotation_simplify(unsigned int rotation, unsigned int supported_rotations);

+extern int drm_plane_atomic_set_zpos_property(struct drm_plane *plane,

• 			      struct drm_plane_state *state,
  

• 			      struct drm_property *property,
  

• 			      uint64_t val);
  

You can drop the extern keywords, they're not needed. I know that lots of functions in this header file use extern, but not all of them do, and moving forward I don't see a big reason to keep using unneeded keywords.

+extern int drm_plane_atomic_get_zpos_property(struct drm_plane *plane,

• 			      const struct drm_plane_state *state,
  

• 			      struct drm_property *property,
  

• 			      uint64_t *val);
  

+extern int drm_plane_create_zpos_property(struct drm_plane *plane,

• 			  unsigned int min, unsigned int max);
  

Shouldn't this be named drm_plane_attach_zpos_property() instead ? The main purpose of the function is to attach the property, even if it has to create it on first invocation as a side effect.

+extern int drm_plane_create_zpos_immutable_property(struct drm_plane *plane,

• 				    unsigned int min,
  

• 				    unsigned int max);
  

/* Helpers */

static inline struct drm_plane *drm_plane_find(struct drm_device *dev,