glx: Unify dri2/dri3 vblank_mode logic.

We need it from kopper, as well.

Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17470>

src/loader/loader_dri3_helper.c

@@ -39,12 +39,6 @@
 #include "util/macros.h"
 #include "drm-uapi/drm_fourcc.h"
 
-/* From driconf.h, user exposed so should be stable */
-#define DRI_CONF_VBLANK_NEVER 0
-#define DRI_CONF_VBLANK_DEF_INTERVAL_0 1
-#define DRI_CONF_VBLANK_DEF_INTERVAL_1 2
-#define DRI_CONF_VBLANK_ALWAYS_SYNC 3
-
 /**
  * A cached blit context.
  */
@@ -397,8 +391,6 @@ loader_dri3_drawable_init(xcb_connection_t *conn,
    xcb_get_geometry_cookie_t cookie;
    xcb_get_geometry_reply_t *reply;
    xcb_generic_error_t *error;
-   GLint vblank_mode = DRI_CONF_VBLANK_DEF_INTERVAL_1;
-   int swap_interval;
 
    draw->conn = conn;
    draw->ext = ext;
@@ -425,9 +417,6 @@ loader_dri3_drawable_init(xcb_connection_t *conn,
    if (draw->ext->config) {
       unsigned char adaptive_sync = 0;
 
-      draw->ext->config->configQueryi(draw->dri_screen,
-                                      "vblank_mode", &vblank_mode);
-
       draw->ext->config->configQueryb(draw->dri_screen,
                                       "adaptive_sync",
                                       &adaptive_sync);
@@ -438,18 +427,8 @@ loader_dri3_drawable_init(xcb_connection_t *conn,
    if (!draw->adaptive_sync)
       set_adaptive_sync_property(conn, draw->drawable, false);
 
-   switch (vblank_mode) {
-   case DRI_CONF_VBLANK_NEVER:
-   case DRI_CONF_VBLANK_DEF_INTERVAL_0:
-      swap_interval = 0;
-      break;
-   case DRI_CONF_VBLANK_DEF_INTERVAL_1:
-   case DRI_CONF_VBLANK_ALWAYS_SYNC:
-   default:
-      swap_interval = 1;
-      break;
-   }
-   draw->swap_interval = swap_interval;
+   draw->swap_interval = dri_get_initial_swap_interval(draw->dri_screen,
+                                                       draw->ext->config);
 
    dri3_update_max_num_back(draw);
 
@@ -487,7 +466,7 @@ loader_dri3_drawable_init(xcb_connection_t *conn,
     * Make sure server has the same swap interval we do for the new
     * drawable.
     */
-   loader_dri3_set_swap_interval(draw, swap_interval);
+   loader_dri3_set_swap_interval(draw, draw->swap_interval);
 
    return 0;
 }

src/loader/loader_dri_helper.c

@@ -72,3 +72,56 @@ __DRIimage *loader_dri_create_image(__DRIscreen *screen,
    return image->createImage(screen, width, height, dri_format, dri_usage,
                              loaderPrivate);
 }
+
+/* From driconf.h, user exposed so should be stable */
+#define DRI_CONF_VBLANK_NEVER 0
+#define DRI_CONF_VBLANK_DEF_INTERVAL_0 1
+#define DRI_CONF_VBLANK_DEF_INTERVAL_1 2
+#define DRI_CONF_VBLANK_ALWAYS_SYNC 3
+
+static int dri_vblank_mode(__DRIscreen *driScreen, const __DRI2configQueryExtension *config)
+{
+   GLint vblank_mode = DRI_CONF_VBLANK_DEF_INTERVAL_1;
+
+   if (config)
+      config->configQueryi(driScreen, "vblank_mode", &vblank_mode);
+
+   return vblank_mode;
+}
+
+int dri_get_initial_swap_interval(__DRIscreen *driScreen,
+                                  const __DRI2configQueryExtension *config)
+{
+   int vblank_mode = dri_vblank_mode(driScreen, config);
+
+   switch (vblank_mode) {
+   case DRI_CONF_VBLANK_NEVER:
+   case DRI_CONF_VBLANK_DEF_INTERVAL_0:
+      return 0;
+   case DRI_CONF_VBLANK_DEF_INTERVAL_1:
+   case DRI_CONF_VBLANK_ALWAYS_SYNC:
+   default:
+      return 1;
+   }
+}
+
+bool dri_valid_swap_interval(__DRIscreen *driScreen,
+                             const __DRI2configQueryExtension *config, int interval)
+{
+   int vblank_mode = dri_vblank_mode(driScreen, config);
+
+   switch (vblank_mode) {
+   case DRI_CONF_VBLANK_NEVER:
+      if (interval != 0)
+         return false;
+      break;
+   case DRI_CONF_VBLANK_ALWAYS_SYNC:
+      if (interval <= 0)
+         return false;
+      break;
+   default:
+      break;
+   }
+
+   return true;
+}

src/loader/loader_dri_helper.h

@@ -31,3 +31,9 @@ __DRIimage *loader_dri_create_image(__DRIscreen *screen,
                                     const uint64_t *modifiers,
                                     unsigned int modifiers_count,
                                     void *loaderPrivate);
+
+int dri_get_initial_swap_interval(__DRIscreen *driScreen,
+                                  const __DRI2configQueryExtension *config);
+
+bool dri_valid_swap_interval(__DRIscreen *driScreen,
+                             const __DRI2configQueryExtension *config, int interval);