hwcontext_vaapi: Add driver quirks to the hwdevice

The driver being used is detected inside av_hwdevice_ctx_init() and
the quirks field then set from a table of known device.  If this
behaviour is unwanted, the user can also set the quirks field
manually.

Also adds the Intel i965 driver quirk (it does not destroy parameter
buffers used in a call to vaRenderPicture()) and detects that driver
to set it.

(cherry picked from commit 4926fa9a4aa03f3b751f52e900b9efb87fea0591)

4 files changed, 66 insertions, 1 deletions

diff --git a/doc/APIchanges b/doc/APIchanges
index eb8e2351ba..e2daed3aca 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,10 @@ libavutil:     2015-08-28
 
 API changes, most recent first:
 
+2016-xx-xx - xxxxxxx - lavu 55.38.100 - hwcontext_vaapi.h
+  Add driver quirks field to VAAPI-specific hwdevice and enum with
+  members AV_VAAPI_DRIVER_QUIRK_* to represent its values.
+
 2016-11-10 - xxxxxxx - lavu 55.36.100 - pixfmt.h
   Add AV_PIX_FMT_GRAY12(LE/BE).
 
diff --git a/libavutil/hwcontext_vaapi.c b/libavutil/hwcontext_vaapi.c
index cfa25bce62..9546550705 100644
--- a/libavutil/hwcontext_vaapi.c
+++ b/libavutil/hwcontext_vaapi.c
@@ -265,12 +265,25 @@ fail:
     return err;
 }
 
+static const struct {
+    const char *friendly_name;
+    const char *match_string;
+    unsigned int quirks;
+} vaapi_driver_quirks_table[] = {
+    {
+        "Intel i965 (Quick Sync)",
+        "i965",
+        AV_VAAPI_DRIVER_QUIRK_RENDER_PARAM_BUFFERS,
+    },
+};
+
 static int vaapi_device_init(AVHWDeviceContext *hwdev)
 {
     VAAPIDeviceContext *ctx = hwdev->internal->priv;
     AVVAAPIDeviceContext *hwctx = hwdev->hwctx;
     VAImageFormat *image_list = NULL;
     VAStatus vas;
+    const char *vendor_string;
     int err, i, image_count;
     enum AVPixelFormat pix_fmt;
     unsigned int fourcc;
@@ -312,6 +325,32 @@ static int vaapi_device_init(AVHWDeviceContext *hwdev)
         }
     }
 
+    if (hwctx->driver_quirks & AV_VAAPI_DRIVER_QUIRK_USER_SET) {
+        av_log(hwdev, AV_LOG_VERBOSE, "Not detecting driver: "
+               "quirks set by user.\n");
+    } else {
+        // Detect the driver in use and set quirk flags if necessary.
+        vendor_string = vaQueryVendorString(hwctx->display);
+        hwctx->driver_quirks = 0;
+        if (vendor_string) {
+            for (i = 0; i < FF_ARRAY_ELEMS(vaapi_driver_quirks_table); i++) {
+                if (strstr(vendor_string,
+                           vaapi_driver_quirks_table[i].match_string)) {
+                    av_log(hwdev, AV_LOG_VERBOSE, "Matched \"%s\" as known "
+                           "driver \"%s\".\n", vendor_string,
+                           vaapi_driver_quirks_table[i].friendly_name);
+                    hwctx->driver_quirks |=
+                        vaapi_driver_quirks_table[i].quirks;
+                    break;
+                }
+            }
+            if (!(i < FF_ARRAY_ELEMS(vaapi_driver_quirks_table))) {
+                av_log(hwdev, AV_LOG_VERBOSE, "Unknown driver \"%s\", "
+                       "assuming standard behaviour.\n", vendor_string);
+            }
+        }
+    }
+
     av_free(image_list);
     return 0;
 fail:
diff --git a/libavutil/hwcontext_vaapi.h b/libavutil/hwcontext_vaapi.h
index 7fd1a36e8f..8bd8031b9d 100644
--- a/libavutil/hwcontext_vaapi.h
+++ b/libavutil/hwcontext_vaapi.h
@@ -33,6 +33,20 @@
  * with the data pointer set to a VASurfaceID.
  */
 
+enum {
+    /**
+     * The quirks field has been set by the user and should not be detected
+     * automatically by av_hwdevice_ctx_init().
+     */
+    AV_VAAPI_DRIVER_QUIRK_USER_SET = (1 << 0),
+    /**
+     * The driver does not destroy parameter buffers when they are used by
+     * vaRenderPicture().  Additional code will be required to destroy them
+     * separately afterwards.
+     */
+    AV_VAAPI_DRIVER_QUIRK_RENDER_PARAM_BUFFERS = (1 << 1),
+};
+
 /**
  * VAAPI connection details.
  *
@@ -43,6 +57,14 @@ typedef struct AVVAAPIDeviceContext {
      * The VADisplay handle, to be filled by the user.
      */
     VADisplay display;
+    /**
+     * Driver quirks to apply - this is filled by av_hwdevice_ctx_init(),
+     * with reference to a table of known drivers, unless the
+     * AV_VAAPI_DRIVER_QUIRK_USER_SET bit is already present.  The user
+     * may need to refer to this field when performing any later
+     * operations using VAAPI with the same VADisplay.
+     */
+    unsigned int driver_quirks;
 } AVVAAPIDeviceContext;
 
 /**
diff --git a/libavutil/version.h b/libavutil/version.h
index a49be1ac9b..81c51815a4 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -79,7 +79,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  55
-#define LIBAVUTIL_VERSION_MINOR  37
+#define LIBAVUTIL_VERSION_MINOR  38
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \