dri2proto: Add DRI2GetParam request

Bump protocol version to 1.4.
Bump package version to 2.7.

This new protocol request effectively allows clients to perform feature
detection on the DDX.

If I had DRI2GetParam in June 2011, when I was implementing support in the
Intel DDX and Mesa for new hardware that required a new DRI2 attachment
format, then I could have avoided a week of pain caused by the necessity
to write a horrid feature detection hack [1] in Mesa. In the future, when
the work begins to add MSAA support to the Intel DDX, having a clean way
to do feature detection will allow us to avoid revisiting and expanding
that hack.

[1] mesa, commit aea2236a, function intel_verify_dri2_has_hi

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Ian Romanick <idr@freedesktop.org>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>

3 files changed, 76 insertions, 3 deletions

diff --git a/configure.ac b/configure.ac
index d671f5a..aeb86a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 AC_PREREQ([2.60])
-AC_INIT([DRI2Proto], [2.6], [https://bugs.freedesktop.org/enter_bug.cgi?product=xorg])
+AC_INIT([DRI2Proto], [2.7], [https://bugs.freedesktop.org/enter_bug.cgi?product=xorg])
 AM_INIT_AUTOMAKE([foreign dist-bzip2])
 AM_MAINTAINER_MODE
 
diff --git a/dri2proto.h b/dri2proto.h
index cd82afb..128b807 100644
--- a/dri2proto.h
+++ b/dri2proto.h
@@ -35,11 +35,11 @@
 
 #define DRI2_NAME                       "DRI2"
 #define DRI2_MAJOR                      1
-#define DRI2_MINOR                      3
+#define DRI2_MINOR                      4
 
 #define DRI2NumberErrors                0
 #define DRI2NumberEvents                2
-#define DRI2NumberRequests              13
+#define DRI2NumberRequests              14
 
 #define X_DRI2QueryVersion              0
 #define X_DRI2Connect                   1
@@ -54,6 +54,7 @@
 #define X_DRI2WaitMSC                   10
 #define X_DRI2WaitSBC                   11
 #define X_DRI2SwapInterval              12
+#define X_DRI2GetParam                  13
 
 /*
  * Events
@@ -330,4 +331,27 @@ typedef struct {
 } xDRI2InvalidateBuffers;
 #define sz_xDRI2InvalidateBuffers 32
 
+typedef struct {
+    CARD8   reqType;
+    CARD8   dri2ReqType;
+    CARD16  length B16;
+    CARD32  drawable B32;
+    CARD32  param B32;
+} xDRI2GetParamReq;
+#define sz_xDRI2GetParamReq 12
+
+typedef struct {
+    BYTE    type; /*X_Reply*/
+    BOOL    is_param_recognized;
+    CARD16  sequenceNumber B16;
+    CARD32  length B32;
+    CARD32  value_hi B32;
+    CARD32  value_lo B32;
+    CARD32  pad1 B32;
+    CARD32  pad2 B32;
+    CARD32  pad3 B32;
+    CARD32  pad4 B32;
+} xDRI2GetParamReply;
+#define sz_xDRI2GetParamReply 32
+
 #endif
diff --git a/dri2proto.txt b/dri2proto.txt
index 7bde067..9921301 100644
--- a/dri2proto.txt
+++ b/dri2proto.txt
@@ -440,6 +440,36 @@ The name of this extension is "DRI2".
         DRI2SwapBuffers requests to swap at most once per interval frames,
         which is useful useful for limiting the frame rate.
 
+┌───
+    DRI2GetParam
+        drawable: DRAWABLE
+        param: CARD32
+      ▶
+        is_param_recognized: BOOL
+        value: CARD64
+└───
+        Errors: Drawable
+
+        Get the value of a parameter.  The parameter's value is looked up on
+        the screen associated with 'drawable'.
+
+        Parameter names in which the value of the most significant byte is
+        0 are reserved for the X server. Currently, no such parameter names
+        are defined. (When any such names are defined, they will be defined in
+        this extension specification and its associated headers).
+
+        Parameter names in which the byte's value is 1 are reserved for the
+        DDX. Such names are private to each driver and shall be defined in the
+        respective driver's headers.
+
+        Parameter names in which the byte's value is neither 0 nor 1 are
+        reserved for future use.
+
+        Possible values of 'is_param_recognized' are true (1) and false (0).
+        If false, then 'value' is undefined.
+
+        This request is only available with protocol version 1.4 or later.
+
                              ⚙ ⚙ ⚙  ⚙ ⚙ ⚙
 
 9. Extension Events
@@ -512,6 +542,8 @@ The DRI2 extension has undergone a number of revisions before
 
         2.6: Enlightenment attained.  Added the DRI2BufferHiz attachment.
 
+        2.7: Added the DRI2GetParam request.
+
 Compatibility up to 2.0 is not preserved, but was also never released.
 
 
@@ -830,6 +862,23 @@ A.2 Protocol Requests
      ▶
 └───
 
+┌───
+    DRI2GetParam
+        1       CARD8                   major opcode
+        1       13                      DRI2 opcode
+        2       8                       length
+        4       DRAWABLE                drawable
+        4       CARD32                  param
+     ▶
+        1       1                       Reply
+        1       BOOL                    is_param_recognized
+        2       CARD16                  sequence number
+        4       0                       reply length
+        4       CARD32                  value_hi
+        4       CARD32                  value_lo
+        16                              unused
+└───
+
 A.3 Protocol Events
 
 The DRI2 extension specifies DRI2_BufferSwapComplete and