[igt-dev] [PATCH i-g-t] tests/fbdev: Add mmap readback subtest

[Imre Deak]

Add a simple subtest checking that the mmap address we get for an FB
corresponds to the content that we read back from the FB via the read
syscall.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 tests/fbdev.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/tests/fbdev.c b/tests/fbdev.c
index e5efeb93d..38623b215 100644
--- a/tests/fbdev.c
+++ b/tests/fbdev.c
@@ -83,6 +83,27 @@ igt_main
 		munmap(map, fix_info.smem_len);
 	}
 
+	igt_subtest("mmap-readback") {
+		const uint32_t pattern = 0x55aa55aa;
+		uint32_t *map;
+		uint32_t buf;
+
+		igt_require(fix_info.smem_len);
+
+		kmstest_set_vt_graphics_mode();
+
+		map = mmap(NULL, fix_info.smem_len,
+			   PROT_WRITE, MAP_SHARED, fd, 0);
+		igt_assert(map != MAP_FAILED);
+
+		map[0] = pattern;
+
+		munmap(map, fix_info.smem_len);
+
+		igt_assert_eq(read(fd, &buf, sizeof(buf)), sizeof(buf));
+		igt_assert_eq(buf, pattern);
+	}
+
 	igt_fixture {
 		close(fd);
 	}
-- 
2.25.1