Revert "zink: remove descriptor-mode selection infrastructure"

this would've been in-use, but khronos changes while I was on vacation
blocked a merge

This reverts commit 3f371d4e94.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20489>

docs/drivers/zink.rst

@@ -249,6 +249,19 @@ are required to be supported
 
   * :ext:`VK_KHR_draw_indirect_count`
 
+Performance
+-----------
+
+If you notice poor performance and high CPU usage while running an application,
+changing the descriptor manager may improve performance:
+
+.. envvar:: ZINK_DESCRIPTORS <mode> ("auto")
+
+``auto``
+   Automatically detect best mode. This is the default.
+``lazy``
+   Attempt to use the least amount of CPU by binding descriptors opportunistically.
+
 Debugging
 ---------
 

src/gallium/drivers/zink/zink_screen.c

@@ -89,6 +89,17 @@ uint32_t
 zink_debug;
 
 
+static const struct debug_named_value
+zink_descriptor_options[] = {
+   { "auto", ZINK_DESCRIPTOR_MODE_AUTO, "Automatically detect best mode" },
+   { "lazy", ZINK_DESCRIPTOR_MODE_LAZY, "Don't cache, do least amount of updates" },
+   DEBUG_NAMED_VALUE_END
+};
+
+DEBUG_GET_ONCE_FLAGS_OPTION(zink_descriptor_mode, "ZINK_DESCRIPTORS", zink_descriptor_options, ZINK_DESCRIPTOR_MODE_AUTO)
+
+enum zink_descriptor_mode zink_descriptor_mode;
+
 static const char *
 zink_get_vendor(struct pipe_screen *pscreen)
 {
@@ -2465,6 +2476,7 @@ zink_internal_create_screen(const struct pipe_screen_config *config)
    screen->abort_on_hang = debug_get_bool_option("ZINK_HANG_ABORT", false);
 
    zink_debug = debug_get_option_zink_debug();
+   zink_descriptor_mode = debug_get_option_zink_descriptor_mode();
 
    screen->loader_lib = util_dl_open(VK_LIBNAME);
    if (!screen->loader_lib)
@@ -2571,6 +2583,9 @@ zink_internal_create_screen(const struct pipe_screen_config *config)
       screen->desc_set_id[ZINK_DESCRIPTOR_TYPE_IMAGE] = 4;
       screen->desc_set_id[ZINK_DESCRIPTOR_BINDLESS] = 5;
    }
+   if (zink_descriptor_mode == ZINK_DESCRIPTOR_MODE_AUTO) {
+      zink_descriptor_mode = ZINK_DESCRIPTOR_MODE_LAZY;
+   }
 
    if (screen->info.have_EXT_calibrated_timestamps && !check_have_device_time(screen))
       goto fail;

src/gallium/drivers/zink/zink_types.h

@@ -146,6 +146,11 @@ enum zink_descriptor_type {
    ZINK_DESCRIPTOR_NON_BINDLESS_TYPES = ZINK_DESCRIPTOR_BASE_TYPES + 1, /**< for struct sizing */
 };
 
+enum zink_descriptor_mode {
+   ZINK_DESCRIPTOR_MODE_AUTO,
+   ZINK_DESCRIPTOR_MODE_LAZY,
+};
+
 /* indexing for descriptor template management */
 enum zink_descriptor_size_index {
    ZDS_INDEX_UBO,