[Mesa-dev] [PATCH 1/5] i965/surface_formats: Don't advertise 8 or 16-bit RGB formats

Jason Ekstrand jason at jlekstrand.net
Wed Jul 27 05:04:22 UTC 2016

We have implicitly been not advertising these formats since we had them
turned off in the format capabilities table.  We are about to update that
table and this prevents a change in behavior.  The only change in behavior
created by this patch is that we no longer advertise support for
R16G16B16_FLOAT which means that it's now renderable which seems like a
bonus.  Maybe someday we'll want to change things to start supporting
16-bit RGB formats natively but, at the moment, there's no need.
 src/mesa/drivers/dri/i965/brw_surface_formats.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_surface_formats.c b/src/mesa/drivers/dri/i965/brw_surface_formats.c
index 2543f4b..69d3bd4 100644
--- a/src/mesa/drivers/dri/i965/brw_surface_formats.c
+++ b/src/mesa/drivers/dri/i965/brw_surface_formats.c
@@ -311,6 +311,16 @@ brw_init_surface_formats(struct brw_context *brw)
       if (texture == 0 && format != MESA_FORMAT_RGBA_FLOAT32)
+      /* Don't advertisel 8 and 16-bit RGB formats to core mesa.  This ensures
+       * that they are renderable from an API perspective since core mesa will
+       * fall back to RGBA or RGBX (we can't render to non-power-of-two
+       * formats).  For 8-bit, formats, this also keeps us from hitting some
+       * nasty corners in intel_miptree_map_blit if you ever try to map one.
+       */
+      int format_size = _mesa_get_format_bytes(format);
+      if (format_size == 3 || format_size == 6)
+         continue;
       if (isl_format_supports_sampling(devinfo, texture) &&
           (isl_format_supports_filtering(devinfo, texture) || is_integer))
 	 ctx->TextureFormatSupported[format] = true;

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