hwcontext_vaapi: Improve logging around quirk detection

Clarify that the list is the naughty list, and therefore being on it is
not desirable.  The i965 driver does not need to be on the list after
version 2.0 (when the standard parameter buffer rendering behaviour was
changed).

libavutil/hwcontext_vaapi.c

@@ -279,11 +279,14 @@ static const struct {
     const char *match_string;
     unsigned int quirks;
 } vaapi_driver_quirks_table[] = {
+#if !VA_CHECK_VERSION(1, 0, 0)
+    // The i965 driver did not conform before version 2.0.
     {
         "Intel i965 (Quick Sync)",
         "i965",
         AV_VAAPI_DRIVER_QUIRK_RENDER_PARAM_BUFFERS,
     },
+#endif
     {
         "Intel iHD",
         "ubit",
@@ -344,29 +347,37 @@ static int vaapi_device_init(AVHWDeviceContext *hwdev)
         }
     }
 
+    vendor_string = vaQueryVendorString(hwctx->display);
+    if (vendor_string)
+        av_log(hwdev, AV_LOG_VERBOSE, "VAAPI driver: %s.\n", vendor_string);
+
     if (hwctx->driver_quirks & AV_VAAPI_DRIVER_QUIRK_USER_SET) {
-        av_log(hwdev, AV_LOG_VERBOSE, "Not detecting driver: "
-               "quirks set by user.\n");
+        av_log(hwdev, AV_LOG_VERBOSE, "Using quirks set by user (%#x).\n",
+               hwctx->driver_quirks);
     } 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);
+                    av_log(hwdev, AV_LOG_VERBOSE, "Matched driver string "
+                           "as known nonstandard driver \"%s\", setting "
+                           "quirks (%#x).\n",
+                           vaapi_driver_quirks_table[i].friendly_name,
+                           vaapi_driver_quirks_table[i].quirks);
                     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_log(hwdev, AV_LOG_VERBOSE, "Driver not found in known "
+                       "nonstandard list, using standard behaviour.\n");
             }
+        } else {
+            av_log(hwdev, AV_LOG_VERBOSE, "Driver has no vendor string, "
+                   "assuming standard behaviour.\n");
         }
     }