gallium: Add PIPE_CAP_QUERY_TIMESTAMP_BITS

For those drivers that don't make full use of the 64 bits in
pipe_query_result.u64.

Applications will make use of it via GL_QUERY_COUNTER_BITS to handle
when the value rolls over.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10770>

docs/gallium/screen.rst

@@ -153,6 +153,8 @@ The integer capabilities:
   pipe_draw_info::start_instance.
 * ``PIPE_CAP_QUERY_TIMESTAMP``: Whether PIPE_QUERY_TIMESTAMP and
   the pipe_screen::get_timestamp hook are implemented.
+* ``PIPE_CAP_QUERY_TIMESTAMP_BITS``: How many bits the driver uses for the
+  results of GL_TIMESTAMP queries.
 * ``PIPE_CAP_TEXTURE_MULTISAMPLE``: Whether all MSAA resources supported
   for rendering are also supported for texturing.
 * ``PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT``: The minimum alignment that should be

src/gallium/auxiliary/util/u_screen.c

@@ -515,6 +515,9 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
                                    PIPE_SHADER_CAP_MAX_SHADER_BUFFERS);
    }
 
+   case PIPE_CAP_QUERY_TIMESTAMP_BITS:
+      return 64;
+
    default:
       unreachable("bad PIPE_CAP_*");
    }

src/gallium/drivers/iris/iris_screen.c

@@ -407,6 +407,9 @@ iris_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
        */
       return devinfo->ver >= 11;
 
+   case PIPE_CAP_QUERY_TIMESTAMP_BITS:
+      return TIMESTAMP_BITS;
+
    default:
       return u_pipe_screen_get_param_defaults(pscreen, param);
    }

src/gallium/drivers/zink/zink_screen.c

@@ -676,6 +676,9 @@ zink_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_QUERY_TIMESTAMP:
       return screen->timestamp_valid_bits > 0;
 
+   case PIPE_CAP_QUERY_TIMESTAMP_BITS:
+      return screen->timestamp_valid_bits;
+
    case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:
       return 1 << MIN_SLAB_ORDER;
 

src/gallium/include/pipe/p_defines.h

@@ -1001,6 +1001,7 @@ enum pipe_cap
    PIPE_CAP_DITHERING,
    PIPE_CAP_FBFETCH_ZS,
    PIPE_CAP_TIMELINE_SEMAPHORE_IMPORT,
+   PIPE_CAP_QUERY_TIMESTAMP_BITS,
 
    PIPE_CAP_LAST,
    /* XXX do not add caps after PIPE_CAP_LAST! */

src/mesa/state_tracker/st_context.c

@@ -559,6 +559,9 @@ st_create_context_priv(struct gl_context *ctx, struct pipe_context *pipe,
                                   PIPE_TEXTURE_2D, 0, 0,
                                   PIPE_BIND_SAMPLER_VIEW);
 
+   ctx->Const.QueryCounterBits.Timestamp =
+      screen->get_param(screen, PIPE_CAP_QUERY_TIMESTAMP_BITS);
+
    st->has_stencil_export =
       screen->get_param(screen, PIPE_CAP_SHADER_STENCIL_EXPORT);
    st->has_etc1 = screen->is_format_supported(screen, PIPE_FORMAT_ETC1_RGB8,