1 files changed, 13 insertions, 1 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_clear.c b/src/mesa/drivers/dri/i965/brw_clear.c
index ce40e52d461..53d8e5400ef 100644
--- a/src/mesa/drivers/dri/i965/brw_clear.c
+++ b/src/mesa/drivers/dri/i965/brw_clear.c
@@ -77,6 +77,18 @@ debug_mask(const char *name, GLbitfield mask)
 }
 
 /**
+ * Returns true if the scissor is a noop (cuts out nothing).
+ */
+static bool
+noop_scissor(struct gl_context *ctx, struct gl_framebuffer *fb)
+{
+   return ctx->Scissor.X <= 0 &&
+          ctx->Scissor.Y <= 0 &&
+          ctx->Scissor.Width >= fb->Width &&
+          ctx->Scissor.Height >= fb->Height;
+}
+
+/**
  * Implements fast depth clears on gen6+.
  *
  * Fast clears basically work by setting a flag in each of the subspans
@@ -107,7 +119,7 @@ brw_fast_clear_depth(struct gl_context *ctx)
     * a previous clear had happened at a different clear value and resolve it
     * first.
     */
-   if (ctx->Scissor.Enabled) {
+   if (ctx->Scissor.Enabled && !noop_scissor(ctx, fb)) {
       perf_debug("Failed to fast clear depth due to scissor being enabled.  "
                  "Possible 5%% performance win if avoided.\n");
       return false;