From: Louis-Francis Ratté-Boulianne <[email protected]>

DRI3 version 1.2 adds support for explicit format modifiers,
including multi-planar buffers.

Signed-off-by: Daniel Stone <[email protected]>
Signed-off-by: Louis-Francis Ratté-Boulianne <[email protected]>
---
 dri3proto.pc.in                    |   2 +-
 dri3proto.txt                      | 319 +++++++++++++++++++++++++++++++++++--
 include/X11/extensions/dri3proto.h |  86 +++++++++-
 meson.build                        |   2 +-
 4 files changed, 396 insertions(+), 13 deletions(-)

diff --git a/dri3proto.pc.in b/dri3proto.pc.in
index 6d81d07..e42d60e 100644
--- a/dri3proto.pc.in
+++ b/dri3proto.pc.in
@@ -5,5 +5,5 @@ includedir=@includedir@
  
 Name: DRI3Proto
 Description: DRI3 extension headers
-Version: 1.0
+Version: 1.2
 Cflags: -I${includedir}
diff --git a/dri3proto.txt b/dri3proto.txt
index dac11d3..94322e7 100644
--- a/dri3proto.txt
+++ b/dri3proto.txt
@@ -1,16 +1,22 @@
                          The DRI3 Extension
-                            Version 1.0
-                              2013-6-4
-      
+                            Version 1.2
+                             2018-02-28
+
                            Keith Packard
                          [email protected]
                          Intel Corporation
 
+                           Daniel Stone
+                      [email protected]
+                            Collabora
+
+
 1. Introduction
 
 The DRI3 extension provides mechanisms to translate between direct
 rendered buffers and X pixmaps. When combined with the Present extension,
-a complete direct rendering solution for OpenGL is provided.
+a complete direct rendering solution for hardware-accelerated devices
+such as GPUs is provided.
 
 The direct rendered buffers are passed across the protocol via
 standard POSIX file descriptor passing mechanisms. On Linux, these
@@ -25,8 +31,9 @@ which can be used to serialize access to shared render 
buffers.
 Eric Anholt <[email protected]>
 Dave Airlie <[email protected]>
 Kristian Høgsberg <[email protected]>
-James Jones <[email protected]>
+James Jones <[email protected]>
 Arthur Huillet <[email protected]>
+Louis-Francis Ratté-Boulianne <[email protected]>
 
                             ❄ ❄ ❄  ❄  ❄ ❄ ❄ 
 
@@ -117,9 +124,10 @@ The name of this extension is "DRI3"
        Errors: Alloc, Drawable, IDChoice, Value, Match
 
        Creates a pixmap for the direct rendering object associated
-       with 'buffer'. Changes to pixmap will be visible in that
-       direct rendered object and changes to the direct rendered
-       object will be visible in the pixmap.
+       with 'buffer' and the screen associated with 'drawable'.
+       Changes to pixmap will be visible in that direct rendered
+       object and changes to the direct rendered object will be
+       visible in the pixmap.
 
        'size' specifies the total size of the buffer bytes. 'width',
        'height' describe the geometry (in pixels) of the underlying
@@ -137,6 +145,9 @@ The name of this extension is "DRI3"
        If depth or bpp are not supported by the screen, a Value error
        is returned.
 
+       For information on synchronization of buffer access between
+       the client and the X server, please see section 12.
+
 ┌───
     DRI3BufferFromPixmap
        pixmap: PIXMAP
@@ -167,6 +178,9 @@ The name of this extension is "DRI3"
        If buffer cannot be used with the screen associated with
        drawable, a Match error is returned.
 
+       For information on synchronization of buffer access between
+       the client and the X server, please see section 12.
+
 ┌───
     DRI3FenceFromFD
        drawable: DRAWABLE
@@ -182,6 +196,9 @@ The name of this extension is "DRI3"
        Details about the mechanism used with this file descriptor are
        outside the scope of the DRI3 extension.
 
+       For information on synchronization of buffer access between
+       the client and the X server, please see section 12.
+
 ┌───
     DRI3FDFromFence
        drawable: DRAWABLE
@@ -199,8 +216,163 @@ The name of this extension is "DRI3"
        associated with a direct rendering device that 'fence' can
        work with, otherwise a Match error results.
 
+       For information on synchronization of buffer access between
+       the client and the X server, please see section 12.
 
-                            ❄ ❄ ❄  ❄  ❄ ❄ ❄ 
+┌───
+    DRI3GetSupportedModifiers
+       window: WINDOW
+       depth: CARD8
+       bpp: CARD8
+      ▶
+       num_window_modifiers: CARD32
+       num_screen_modifiers: CARD32
+       window_modifiers: ListOfCARD64
+       screen_modifiers: ListOfCARD64
+└───
+       Errors: Window, Match
+
+       Return supported DRM FourCC modifiers for the specified
+       'window'.
+
+       The first list of 'window_modifiers' contains a set of
+       modifiers which the server considers optimal for the window's
+       current configuration. Using these modifiers to allocate, even
+       if locally suboptimal to the client driver, may result in a
+       more optimal display pipeline, e.g. by avoiding composition.
+
+       The second list of 'screen_modifiers', is the total set of
+       modifiers which are acceptable for use on the Screen associated
+       with 'window'. This set of modifiers will not change over the
+       lifetime of the client. Using this set of modifiers to allocate
+       may not result in a globally optimal pipeline, if separate
+       'window_modifiers' are available.
+
+       It is expected that a client calling this request will obtain
+       the modifiers for a particular window, allocate buffers using
+       the preferred modifier set as described above, create a Pixmap
+       referring to the storage of those buffers using the
+       DRI3BuffersFromPixmap request, then make the content visible
+       in the storage of those buffers visible with a request such as
+       the Present extension's PresentPixmap.
+
+       The meaning of any modifier is canonically defined in
+       drm_fourcc.h.
+
+┌───
+    DRI3PixmapFromBuffers
+       pixmap: PIXMAP
+       window: WINDOW
+       num_buffers: CARD8
+       width, height: CARD16
+       stride0, offset0: CARD32
+       stride1, offset1: CARD32
+       stride2, offset2: CARD32
+       stride3, offset3: CARD32
+       depth, bpp: CARD8
+       modifier: CARD64
+       buffers: ListOfFD
+└───
+       Errors: Alloc, Window, IDChoice, Value, Match
+
+       Creates a pixmap for the direct rendering object associated
+       with 'buffers' and the screen associated with 'window'.
+       Changes to pixmap will be visible in that direct rendered
+       object and changes to the direct rendered object will be
+       visible in the pixmap. The pixmap will be available for
+       presentation to the window.
+
+       In contrast to PixmapFromBuffer, multiple buffers may be
+       combined to specify a single logical source for pixel
+       sampling: 'num_buffers' may be set from 1 (single buffer,
+       akin to PixmapFromBuffer) to 4. This is the number of file
+       descriptors which will be sent with this request; one per
+       buffer.
+
+       Modifiers allow explicit specification of non-linear sources,
+       such as tiled or compressed buffers. The combination of bpp,
+       depth, and modifier allows unambiguous declaration of the
+       buffer layout in a manner defined by the DRM tokens.
+
+       If 'modifier' is DRM_FORMAT_MOD_INVALID, the client does
+       not have information on the buffer layout. In this case, the
+       buffer may only have a single plane. The driver may make its
+       own inference through unspecified means to determine the exact
+       buffer layout, however this is neither required nor defined
+       by the specification, and is considered an implementation
+       detail of the particular driver.
+
+       'width' and 'height' describe the geometry (in pixels) of the
+       logical pixel-sample source.
+
+       'strideN' and 'offsetN' define the number of bytes per logical
+       scanline, and the distance in bytes from the beginning of the
+       buffer passed for that plane until the start of the sample
+       source for that plane, respectively for plane N. If the plane
+       is not used according to the format and modifier specification,
+       both values for that plane must be zero.
+
+       Precisely how any additional information about the buffer (such
+       as memory placement) is shared is outside the scope of this
+       extension.
+
+       If the buffer(s) cannot be used with the screen associated with
+       'window', a Match error is returned.
+
+       If the bpp, depth, and modifier combination is not supported by
+       the screen, a Value error is returned.
+
+       For information on synchronization of buffer access between
+       the client and the X server, please see section 12.
+
+┌───
+    DRI3BuffersFromPixmap
+       pixmap: PIXMAP
+      ▶
+       nfd: CARD8
+       width, height: CARD16
+       depth, bpp: CARD8
+       modifier: CARD64
+       strides: ListOfCARD32
+       offsets: ListOfCARD32
+       buffers: ListOfFD
+└───
+       Errors: Pixmap, Match
+
+       Returns direct rendering objects associated with 'pixmap'.
+       Changes to 'pixmap' will be visible in the direct rendered
+       objects and changes to the direct rendered objects will be
+       visible in 'pixmap' after flushing and synchronization.
+
+       'width' and 'height' describe the geometry (in pixels) of the
+       logical pixel-sample source from combining the direct rendering
+       objects.
+
+       See PixmapFromBuffers for more details on DRM modifiers usage.
+
+       'nfd' describes the number of buffers returned for the pixmap,
+       which must be combined together according to 'depth', 'bpp', and
+       'modifier'.
+
+       For each buffer, there is an entry in the 'strides',
+       'offsets', and 'buffers' list. 'buffer' contains a single file
+       descriptor referring to the buffer. 'stride' specifies the
+       number of bytes per logical scanline for this plane, and
+       'offset' specifies the distance in bytes from the beginning
+       of 'buffer' until the start of the sample source for that
+       plane.
+
+       Precisely how any additional information about the buffer is
+       shared is outside the scope of this extension.
+
+       If buffers cannot be exported from the the screen associated
+       with 'pixmap', a Match error is returned.
+
+       For information on synchronization of buffer access between
+       the client and the X server, please see section 12.
+
+
+                            ❄ ❄ ❄  ❄  ❄ ❄ ❄
 
 9. Extension Events
 
@@ -214,6 +386,11 @@ The DRI3 extension is adapted from the DRI2 extension.
 
        1.0: First published version
 
+       1.1: Cosmetic changes
+
+       1.2: Add GetSupportedModifiers,
+            PixmapFromBuffers, and BuffersFromPixmap requests.
+
                             ❄ ❄ ❄  ❄  ❄ ❄ ❄
 
 
@@ -249,6 +426,57 @@ objects from the X server.
 
                             ❄ ❄ ❄  ❄  ❄ ❄ ❄
 
+12. Synchronization
+
+Synchronization of access to buffers shared between processes is not
+currently explicitly controlled by this protocol.
+
+Without the use of additional extensions not defined by the DRI3
+protocol as of version 1.2, synchronization between multiple
+processes and contexts is considered to follow the implicit model.
+
+In this model, the driver is required to have a global view of
+access requests issued by all processes with a reference to the
+buffer, and control scheduling of all operations on that buffer,
+whether performed by the CPU or auxiliary hardware.
+
+The driver is responsible for enforcing a strict ordering to protect
+against write-after-read or read-after-write hazards, such that any
+reads requested by one process or context, are fulfilled before any
+writes requested by another process or context, as long as that read
+was definitively submitted before the write.
+
+A similar dependency exists for reads submitted after writes: the
+driver must ensure that the write is fully visible and coherent to
+the read request.
+
+As a purely illustrative example, if two processes share a buffer,
+where one process reads from a buffer using an OpenGL texture
+sampler and submits this work by calling 'glFlush', and the other
+process submits work to the driver to write to that buffer, the
+driver is responsible for ensuring that the results of the latter
+write are not visible to the texture sampler.
+
+The Sync fences provided by DRI3 control only this submission of
+work and ensuing global visibility of the requests, rather than the
+completion of the work within any hardware. To further the example
+above, a fence used to prevent any writes to the buffer before the
+sampler had completed access, the fence would be signaled when
+'glFlush' had been called, at which point the request has become
+globally visible to the driver's request-scheduling and
+synchronization mechanisms. The logical ordering of requests made
+by software has been preserved, and the driver then takes care
+to ensure that these requests are scheduled such they do not
+observe effects from requests made later in time.
+
+This presents a fully coherent in-order FIFO-like model across
+processes, where synchronzation is handled externally to the DRI3
+client with no explicit intervention.
+
+This restriction also applies for cross-device usage.
+
+                            ❄ ❄ ❄  ❄  ❄ ❄ ❄
+
 Appendix A. Protocol Encoding
 
 Syntactic Conventions
@@ -367,6 +595,79 @@ A.2 Protocol Requests
        0       FD                      fence fd
 └───
 
+┌───
+    DRI3GetSupportedModifiers
+       1       CARD8                   major opcode
+       1       7                       DRI3 opcode
+       2       3                       length
+       4       Window                  window
+       1       CARD8                   depth
+       1       CARD8                   bpp
+       2                               unused
+      ▶
+       1       1                       Reply
+        1      0                       unused
+       2       CARD16                  sequence number
+       4       CARD32                  reply length
+       4       CARD32                  num_window_modifiers
+       4       CARD32                  num_screen_modifiers
+       16                              unused
+
+       4       ListOfCARD64            window_modifiers[num_window_modifiers]
+       4       ListOfCARD64            screen_modifiers[num_screen_modifiers]
+└───
+
+┌───
+    DRI3PixmapFromBuffers
+       1       CARD8                   major opcode
+       1       8                       DRI3 opcode
+       2       8                       length
+       4       Pixmap                  pixmap
+       4       Window                  window
+       1       CARD8                   num_buffers
+       3                               unused
+       2       CARD16                  width
+       2       CARD16                  height
+       4       CARD32                  stride0
+       4       CARD32                  offset0
+       4       CARD32                  stride1
+       4       CARD32                  offset1
+       4       CARD32                  stride2
+       4       CARD32                  offset2
+       4       CARD32                  stride3
+       4       CARD32                  offset3
+       1       CARD8                   depth
+       1       CARD8                   bpp
+       2                               unused
+       8       CARD64                  modifier
+
+       0       ListOfFD                buffers[num_buffers]
+└───
+
+┌───
+    DRI3BuffersFromPixmap
+       1       CARD8                   major opcode
+       1       9                       DRI3 opcode
+       2       2                       length
+       4       Pixmap                  pixmap
+      ▶
+       1       1                       Reply
+        1      CARD8                   nfd
+       2       CARD16                  sequence number
+       4       CARD32                  reply length
+       2       CARD16                  width
+       2       CARD16                  height
+       4       CARD8                   unused
+       8       CARD64                  modifier
+       1       CARD8                   depth
+       1       CARD8                   bpp
+       6                               unused
+
+       0       ListOfFD                buffer[nfd]
+       4       ListOfCARD32            strides[nfd]
+       4       ListOfCARD32            offsets[nfd]
+└───
+
 A.3 Protocol Events
 
 The DRI3 extension defines no events.
diff --git a/include/X11/extensions/dri3proto.h 
b/include/X11/extensions/dri3proto.h
index ceddee8..51b825d 100644
--- a/include/X11/extensions/dri3proto.h
+++ b/include/X11/extensions/dri3proto.h
@@ -25,7 +25,7 @@
 
 #define DRI3_NAME                      "DRI3"
 #define DRI3_MAJOR                     1
-#define DRI3_MINOR                     0
+#define DRI3_MINOR                     2
 
 #define DRI3NumberErrors               0
 #define DRI3NumberEvents               0
@@ -37,7 +37,12 @@
 #define X_DRI3FenceFromFD               4
 #define X_DRI3FDFromFence               5
 
-#define DRI3NumberRequests             6
+/* v1.2 */
+#define xDRI3GetSupportedModifiers      6
+#define xDRI3PixmapFromBuffers          7
+#define xDRI3BuffersFromPixmap          8
+
+#define DRI3NumberRequests             9
 
 typedef struct {
     CARD8   reqType;
@@ -164,4 +169,81 @@ typedef struct {
 
 #define sz_xDRI3FDFromFenceReply   32
 
+/* v1.2 */
+
+typedef struct {
+    CARD8   reqType;
+    CARD8   dri3ReqType;
+    CARD16  length B16;
+    CARD32  window B32;
+    CARD8   depth;
+    CARD8   bpp;
+    CARD16  pad10 B16;
+} xDRI3GetSupportedModifiersReq;
+#define sz_xDRI3GetSupportedModifiersReq     12
+
+typedef struct {
+    BYTE    type;   /* X_Reply */
+    CARD8   pad1;
+    CARD16  sequenceNumber B16;
+    CARD32  length B32;
+    CARD32  numWindowModifiers B32;
+    CARD32  numScreenModifiers B32;
+    CARD32  pad16 B32;
+    CARD32  pad20 B32;
+    CARD32  pad24 B32;
+    CARD32  pad28 B32;
+} xDRI3GetSupportedModifiersReply;
+#define sz_xDRI3GetSupportedModifiersReply   32
+
+typedef struct {
+    CARD8   reqType;
+    CARD8   dri3ReqType;
+    CARD16  length B16;
+    CARD32  pixmap B32;
+    CARD32  window B32;
+    CARD8   num_buffers; /* Number of file descriptors passed */
+    CARD8   pad13;
+    CARD16  pad14 B16;
+    CARD16  width B16;
+    CARD16  height B16;
+    CARD32  stride0 B32;
+    CARD32  offset0 B32;
+    CARD32  stride1 B32;
+    CARD32  offset1 B32;
+    CARD32  stride2 B32;
+    CARD32  offset2 B32;
+    CARD32  stride3 B32;
+    CARD32  offset3 B32;
+    CARD8   depth;
+    CARD8   bpp;
+    CARD16  pad54 B16;
+    CARD64  modifier;
+} xDRI3PixmapFromBuffersReq;
+#define sz_xDRI3PixmapFromBuffersReq 64
+
+typedef struct {
+    CARD8   reqType;
+    CARD8   dri3ReqType;
+    CARD16  length B16;
+    CARD32  pixmap B32;
+} xDRI3BuffersFromPixmapReq;
+#define sz_xDRI3BuffersFromPixmapReq     8
+
+typedef struct {
+    BYTE    type;   /* X_Reply */
+    CARD8   nfd;    /* Number of file descriptors returned */
+    CARD16  sequenceNumber B16;
+    CARD32  length B32;
+    CARD16  width B16;
+    CARD16  height B16;
+    CARD32  pad12 B32;
+    CARD64  modifier;
+    CARD8   depth;
+    CARD8   bpp;
+    CARD16  pad26 B16;
+    CARD32  pad28 B32;
+} xDRI3BuffersFromPixmapReply;
+#define sz_xDRI3BuffersFromPixmapReply   32
+
 #endif
diff --git a/meson.build b/meson.build
index 9511029..cb92280 100644
--- a/meson.build
+++ b/meson.build
@@ -30,7 +30,7 @@ pcs = [
         ['damageproto',         '1.2.1'],
         ['dmxproto',            '2.3.1'],
         ['dri2proto',           '2.8'],
-        ['dri3proto',           '1.0'],
+        ['dri3proto',           '1.2'],
         ['fixesproto',          '5.0'],
         ['fontsproto',          '2.1.3'],
         ['glproto',             '1.4.17'],
-- 
2.14.3

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