This patch adds code and documentation for the following blending
related properties: 'alpha', 'blending' and 'alpha_premult'.
'alpha' property defines plane's transparency used for some blending
modes.
'alpha_premult' property defines if RGB pixel data in the framebuffer
contains values pre-multiplied by its alpha value or full range RGB
values (0-255), which needs to be multiplied by pixel alpha value for
blending operation.
'blending' property selects blending mode - by selecting one of the
predefined values, user can select a pair of factors, which will be
used in the generic blending equation. For more information, see
the kerneldoc for the added code.
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
Documentation/DocBook/gpu.tmpl | 47 +++++++++++++++++-
drivers/gpu/drm/drm_atomic.c | 12 +++++
drivers/gpu/drm/drm_blend.c | 110 +++++++++++++++++++++++++++++++++++++++++
include/drm/drm_crtc.h | 15 ++++++
include/uapi/drm/drm_mode.h | 101 +++++++++++++++++++++++++++++++++++++
5 files changed, 283 insertions(+), 2 deletions(-)
diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl
index ae7d913adf60..e5197368e68f 100644
--- a/Documentation/DocBook/gpu.tmpl
+++ b/Documentation/DocBook/gpu.tmpl
@@ -1110,6 +1110,22 @@ int max_width, max_height;</synopsis>
</sect2>
</sect1>
+ <!-- Internals: plane blending -->
+
+ <sect1 id="drm-plane-blending">
+ <title>Plane blending</title>
+
+ <sect2>
+ <title>Plane Blending Overview</title>
+!Pinclude/uapi/drm/drm_mode.h Generic plane blending operation
+ </sect2>
+ <sect2>
+ <title>Blending Function Reference</title>
+!Iinclude/uapi/drm/drm_mode.h
+!Edrivers/gpu/drm/drm_blend.c
+ </sect2>
+ </sect1>
+
<!-- Internals: kms initialization and cleanup -->
<sect1 id="drm-kms-init">
@@ -1816,7 +1832,7 @@ void intel_crt_init(struct drm_device *dev)
<td valign="top" >Description/Restrictions</td>
</tr>
<tr>
- <td rowspan="38" valign="top" >DRM</td>
+ <td rowspan="41" valign="top" >DRM</td>
<td valign="top" >Generic</td>
<td valign="top" >“rotation”</td>
<td valign="top" >BITMASK</td>
@@ -2068,7 +2084,7 @@ void intel_crt_init(struct drm_device *dev)
<td valign="top" >property to suggest an Y offset for a connector</td>
</tr>
<tr>
- <td rowspan="4" valign="top" >Optional</td>
+ <td rowspan="7" valign="top" >Optional</td>
<td valign="top" >“scaling mode”</td>
<td valign="top" >ENUM</td>
<td valign="top" >{ "None", "Full", "Center", "Full aspect" }</td>
@@ -2102,6 +2118,33 @@ void intel_crt_init(struct drm_device *dev)
planes' order. Exact value range is driver dependent.</td>
</tr>
<tr>
+ <td valign="top" > "alpha" </td>
+ <td valign="top" >RANGE</td>
+ <td valign="top" >Min=0, Max= driver dependent</td>
+ <td valign="top" >Plane</td>
+ <td valign="top" >Plane's alpha value (transparency) for blending operation. Used in some blending modes. </td>
+ </tr>
+ <tr>
+ <td valign="top" > "alpha_premult" </td>
+ <td valign="top" >BOOL</td>
+ <td valign="top" >Min=0, Max=1</td>
+ <td valign="top" >Plane</td>
+ <td valign="top" >Indicates the range of the RGB data of the framebuffer attached to the given plane.
+ When enabled, RGB values fits the range from 0 to pixel's alpha value. When disabled, RGB
+ values are from 0 to 255 range and during blending operations they will be multiplied by
+ the pixel's alpha value first before computing result of blending equations. Value of this
+ property is used in some blending modes and only when user attaches framebuffer with pixel
+ format, which contains non-binary alpha channel.</td>
+ </tr>
+ <tr>
+ <td valign="top" > "blending" </td>
+ <td valign="top" >ENUM</td>
+ <td valign="top" >{ "disabled", "pixel-alpha", "const-alpha" "pixel-const-alpha" }</td>
+ <td valign="top" >Plane</td>
+ <td valign="top" >Selects algorithm used in plane blending operation. For more information, see
+ DRM_BLEND_* symbolic constant documentation. </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/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index a19201efb7d1..a85da144fd95 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -632,6 +632,12 @@ int drm_atomic_plane_set_property(struct drm_plane *plane,
state->rotation = val;
} else if (property == config->zpos_property) {
state->zpos = val;
+ } else if (property == config->alpha_property) {
+ state->alpha = val;
+ } else if (property == config->alpha_premult_property) {
+ state->alpha_premult = val;
+ } else if (property == config->blending_property) {
+ state->blending = val;
} else if (plane->funcs->atomic_set_property) {
return plane->funcs->atomic_set_property(plane, state,
property, val);
@@ -690,6 +696,12 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
*val = state->rotation;
} else if (property == config->zpos_property) {
*val = state->zpos;
+ } else if (property == config->alpha_property) {
+ *val = state->alpha;
+ } else if (property == config->alpha_premult_property) {
+ *val = state->alpha_premult;
+ } else if (property == config->blending_property) {
+ *val = state->blending;
} else if (plane->funcs->atomic_get_property) {
return plane->funcs->atomic_get_property(plane, state, property, val);
} else {
diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index cdcb647c8ed9..eb7996a848df 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -99,6 +99,116 @@ int drm_mode_create_zpos_immutable_property(struct drm_device *dev,
}
EXPORT_SYMBOL(drm_mode_create_zpos_immutable_property);
+/**
+ * drm_mode_create_blending_property - create generic blending property
+ * @dev: DRM device
+ * @supported_blendings: array of supported blending modes
+ * @supported_blendings_count: size of @supported_blendings array
+ *
+ * This function initializes generic blending property to selected subset
+ * of supported blending modes. Drivers can then attach this property to
+ * planes to let userspace to configure different blending modes. For more
+ * information on blending modes, see DRM_BLEND_* defines.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_create_blending_property(struct drm_device *dev,
+ unsigned int *supported_blendings,
+ unsigned int supported_blendings_count)
+{
+ struct drm_property *prop;
+ static const struct drm_prop_enum_list all_values[] = {
+ { DRM_BLEND_DISABLED, "disabled" },
+ { DRM_BLEND_PIXEL_ALPHA, "pixel-alpha" },
+ { DRM_BLEND_CONST_ALPHA, "const-alpha" },
+ { DRM_BLEND_PIXEL_CONST_ALPHA, "pixel-const-alpha" },
+ };
+ struct drm_prop_enum_list *values;
+ int i, j;
+
+ values = kmalloc(supported_blendings_count * sizeof(*values),
+ GFP_KERNEL);
+ if (!values)
+ return -ENOMEM;
+
+ for (i = 0; i < supported_blendings_count; i++) {
+ for (j = 0; j < ARRAY_SIZE(all_values); j++) {
+ if (all_values[j].type == supported_blendings[i]) {
+ values[i].type = supported_blendings[i];
+ values[i].name = all_values[j].name;
+ break;
+ }
+ }
+ }
+
+ prop = drm_property_create_enum(dev, 0, "blending", values,
+ supported_blendings_count);
+ kfree(values);
+
+ if (!prop)
+ return -ENOMEM;
+
+ dev->mode_config.blending_property = prop;
+ return 0;
+}
+EXPORT_SYMBOL(drm_mode_create_blending_property);
+
+/**
+ * drm_mode_create_alpha_property - create plane alpha property
+ * @dev: DRM device
+ * @max: maximal possible value of alpha property
+ *
+ * This function initializes generic plane's alpha property. It's value is used
+ * for blending operations, depending on selected blending mode. For more
+ * information, see DRM_BLEND_* modes and its documentation. Maximum alpha value
+ * is determined by the driver.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_create_alpha_property(struct drm_device *dev, unsigned int max)
+{
+ struct drm_property *prop;
+
+ prop = drm_property_create_range(dev, 0, "alpha", 0, max);
+ if (!prop)
+ return -ENOMEM;
+
+ dev->mode_config.alpha_property = prop;
+ return 0;
+}
+EXPORT_SYMBOL(drm_mode_create_alpha_property);
+
+/**
+ * drm_mode_create_alpha_premult_property - create muttable zpos property
+ * @dev: DRM device
+ *
+ * This function initializes generic plane's alpha pre-multiplication property.
+ * This property indicates the range of the RGB data of the framebuffer attached
+ * to the given plane. When enabled, RGB values fits the range from 0 to pixel's
+ * alpha value. When disabled, RGB values are from 0 to 255 range and during
+ * blending operations they will be multiplied by the pixel's alpha value first
+ * before computing result of blending equations. Value of this property is used
+ * only when user attaches framebuffer with pixel format, which contains
+ * non-binary alpha channel (for example: DRM_FORMAT_ARGB8888).
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_create_alpha_premult_property(struct drm_device *dev)
+{
+ struct drm_property *prop;
+
+ prop = drm_property_create_bool(dev, 0, "alpha_premult");
+ if (!prop)
+ return -ENOMEM;
+
+ dev->mode_config.alpha_premult_property = prop;
+ return 0;
+}
+EXPORT_SYMBOL(drm_mode_create_alpha_premult_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;
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 702f4f28f580..47ae79483a19 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1276,6 +1276,11 @@ struct drm_plane_state {
unsigned int zpos;
unsigned int normalized_zpos;
+ /* Plane blending */
+ unsigned int blending;
+ unsigned int alpha;
+ bool alpha_premult;
+
struct drm_atomic_state *state;
};
@@ -2098,6 +2103,9 @@ struct drm_mode_config {
struct drm_property *rotation_property;
struct drm_property *zpos_property;
struct drm_property *zpos_immutable_property;
+ struct drm_property *blending_property;
+ struct drm_property *alpha_property;
+ struct drm_property *alpha_premult_property;
struct drm_property *prop_src_x;
struct drm_property *prop_src_y;
struct drm_property *prop_src_w;
@@ -2505,6 +2513,13 @@ extern int drm_mode_create_zpos_immutable_property(struct drm_device *dev,
unsigned int min,
unsigned int max);
+extern int drm_mode_create_blending_property(struct drm_device *dev,
+ unsigned int *supported_blendings,
+ unsigned int supported_blendings_count);
+extern int drm_mode_create_alpha_property(struct drm_device *dev,
+ unsigned int max);
+extern int drm_mode_create_alpha_premult_property(struct drm_device *dev);
+
/* Helpers */
static inline struct drm_plane *drm_plane_find(struct drm_device *dev,
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 50adb46204c2..6da7076a3856 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -596,4 +596,105 @@ struct drm_mode_destroy_blob {
__u32 blob_id;
};
+/**
+ * DOC: Generic plane blending operation
+ *
+ * Planes attached to one CRTC are blended by the hardware to produce the final
+ * result on the display. The order of planes during blending operation is
+ * determined by 'zpos' property. When order of plane for blending operation is
+ * determined, then framebuffers of all planes are placed on the display area
+ * according to the configured position and target size.
+ *
+ * Then one of the selected blending procedure is applied to each pixel on the
+ * display area to compute the final result of the blending. The blending
+ * procedure is similar to the well known glBlendFunc() API.
+ *
+ * The generic equation for blending is:
+ * outputRGB = sF * sRGB + dF * dRGB
+ *
+ * @sRGB: are RGB values of blended plane
+ *
+ * @dRGB: are RGB values of plane's background (result of previous blending or
+ * RGB pixel values of deeper planes).
+ *
+ * @sF and @dF: are one of DRM_FACTOR_* symbolic constants.
+ *
+ * Blending mode then defined as DRM_BLEND(sF, dF), which selects respective
+ * factors for the above equation. For more information, see drm_blend_mode
+ * enum.
+ */
+
+/**
+ * enum drm_blend_factor - factors for defining plane blending formula
+ * @DRM_FACTOR_ZERO: constant zero
+ * @DRM_FACTOR_ONE: constant one
+ * @DRM_FACTOR_SRC_ALPHA: pixel alpha value
+ * @DRM_FACTOR_ONE_MINUS_SRC_ALPHA: 1 - DRM_FACTOR_SRC_ALPHA
+ * @DRM_FACTOR_CONST_ALPHA: constant alpha (plane's property)
+ * @DRM_FACTOR_ONE_MINUS_CONST_ALPHA: 1 - DRM_FACTOR_CONST_ALPHA
+ * @DRM_FACTOR_SRC_CONST_ALPHA: pixel alpha value multiplied by plane's
+ * constant alpha
+ * @DRM_FACTOR_ONE_MINUS_SRC_CONST_ALPHA: 1 - DRM_FACTOR_SRC_CONST_ALPHA
+ *
+ * Values of this enum are used to define plane blending formula. Two factors
+ * have to be selected - one for source plane and one for destination
+ * (background).
+ */
+enum drm_blend_factor {
+ DRM_FACTOR_ZERO,
+ DRM_FACTOR_ONE,
+ DRM_FACTOR_SRC_ALPHA,
+ DRM_FACTOR_ONE_MINUS_SRC_ALPHA,
+ DRM_FACTOR_CONST_ALPHA,
+ DRM_FACTOR_ONE_MINUS_CONST_ALPHA,
+ DRM_FACTOR_SRC_CONST_ALPHA,
+ DRM_FACTOR_ONE_MINUS_SRC_CONST_ALPHA,
+};
+
+#define DRM_BLEND(s, d) ((d << 16) | (s))
+
+/**
+ * enum drm_blend_mode - predefined blending modes
+ * @DRM_BLEND_S_ONE_D_ZERO: no transparency; per-pixel and plane's alpha is
+ * ignored regardless of the selected pixel format.
+ * @DRM_BLEND_S_SRC_ALPHA_D_ONE_MINUS_SRC_ALPHA: blending with per-pixel alpha;
+ * plane's alpha is ignored, aplies only when pixel format defines alpha
+ * channel, otherwise same as @DRM_BLEND_DISABLED and
+ * @DRM_BLEND_S_ONE_D_ZERO.
+ * @DRM_BLEND_S_CONST_ALPHA_D_ONE_MINUS_CONST_ALPHA: blending with constant
+ * alpha; per-pixel alpha is ignored regardless of the selected pixel
+ * format.
+ * @DRM_BLEND_S_SRC_CONST_ALPHA_D_ONE_MINUS_SRC_CONST_ALPHA: blending with both
+ * per-pixel and plane's alpha; aplies only when pixel format defines alpha
+ * channel, otherwise same as @DRM_BLEND_CONST_ALPHA and
+ * @DRM_BLEND_S_CONST_ALPHA_D_ONE_MINUS_CONST_ALPHA
+ * @DRM_BLEND_DISABLED: same as @DRM_BLEND_S_ONE_D_ZERO
+ * @DRM_BLEND_PIXEL_ALPHA: same as @DRM_BLEND_S_SRC_ALPHA_D_ONE_MINUS_SRC_ALPHA,
+ * @DRM_BLEND_CONST_ALPHA: same as
+ * @DRM_BLEND_S_CONST_ALPHA_D_ONE_MINUS_CONST_ALPHA,
+ * @DRM_BLEND_PIXEL_CONST_ALPHA: same as
+ * @DRM_BLEND_S_SRC_CONST_ALPHA_D_ONE_MINUS_SRC_CONST_ALPHA,
+ *
+ * Values of this enum can be set to 'blend' plane's property. The actual
+ * value of each blending mode consists of two drm_blend_factor values
+ * encoded on lower 16 bits for source plane and higher 16 bits for destiantion
+ * (background).
+ */
+enum drm_blend_mode {
+ DRM_BLEND_S_ONE_D_ZERO = DRM_BLEND(DRM_FACTOR_ONE, DRM_FACTOR_ZERO),
+ DRM_BLEND_S_SRC_ALPHA_D_ONE_MINUS_SRC_ALPHA =
+ DRM_BLEND(DRM_FACTOR_SRC_ALPHA,
+ DRM_FACTOR_ONE_MINUS_SRC_ALPHA),
+ DRM_BLEND_S_CONST_ALPHA_D_ONE_MINUS_CONST_ALPHA =
+ DRM_BLEND(DRM_FACTOR_CONST_ALPHA,
+ DRM_FACTOR_ONE_MINUS_CONST_ALPHA),
+ DRM_BLEND_S_SRC_CONST_ALPHA_D_ONE_MINUS_SRC_CONST_ALPHA =
+ DRM_BLEND(DRM_FACTOR_SRC_CONST_ALPHA,
+ DRM_FACTOR_ONE_MINUS_SRC_CONST_ALPHA),
+ DRM_BLEND_DISABLED = DRM_BLEND_S_ONE_D_ZERO,
+ DRM_BLEND_PIXEL_ALPHA = DRM_BLEND_S_SRC_ALPHA_D_ONE_MINUS_SRC_ALPHA,
+ DRM_BLEND_CONST_ALPHA = DRM_BLEND_S_CONST_ALPHA_D_ONE_MINUS_CONST_ALPHA,
+ DRM_BLEND_PIXEL_CONST_ALPHA = DRM_BLEND_S_SRC_CONST_ALPHA_D_ONE_MINUS_SRC_CONST_ALPHA,
+};
+
#endif
--
1.9.2
--
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