igt/gem_streaming_writes: Build in a self-test

Use the first pass to write all values prior to the initial execbuf to
verify that the copy itself is true. Subsequent passes then focus on
verifying that writing values whilst the GPU is reading from
neighbouring values is then correct.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 9 insertions, 2 deletions

diff --git a/tests/gem_streaming_writes.c b/tests/gem_streaming_writes.c
index da13dab3..d42a184a 100644
--- a/tests/gem_streaming_writes.c
+++ b/tests/gem_streaming_writes.c
@@ -171,12 +171,19 @@ static void test_streaming(int fd, int mode)
 		int domain = mode ? I915_GEM_DOMAIN_GTT : I915_GEM_DOMAIN_CPU;
 		gem_set_domain(fd, src, domain, domain);
 
+		if (pass == 0) {
+			for (i = 0; i < OBJECT_SIZE/4; i++)
+				s[i] = i;
+		}
+
 		/* Now copy from the src to the dst in 32byte chunks */
 		for (offset = 0; offset < OBJECT_SIZE; offset += CHUNK_SIZE) {
 			int b;
 
-			for (i = 0; i < CHUNK_SIZE/4; i++)
-				s[offset/4 + i] = (OBJECT_SIZE*pass + offset)/4 + i;
+			if (pass) {
+				for (i = 0; i < CHUNK_SIZE/4; i++)
+					s[offset/4 + i] = (OBJECT_SIZE*pass + offset)/4 + i;
+			}
 
 			b = offset / CHUNK_SIZE / 64;
 			n = offset / CHUNK_SIZE % 64;