[Intel-gfx] [PATCH] igt: Correct the return value for drm short_buffer read

[Xiong Zhang]

After i915 commit:
commit bd008e5b2953186fc0c6633a885ade95e7043800
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Tue Oct 7 14:13:51 2014 +0100

    drm: Implement O_NONBLOCK support on /dev/dri/cardN

the return value for drm short_buffer read is -1 and errno is
EAGAIN.

Signed-off-by: Xiong Zhang <xiong.y.zhang at intel.com>
---
 tests/drm_read.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/drm_read.c b/tests/drm_read.c
index 334f26a..a17d981 100644
--- a/tests/drm_read.c
+++ b/tests/drm_read.c
@@ -145,7 +145,8 @@ static void test_short_buffer(int in, int nonblock)
 
 	alarm(3);
 
-	igt_assert_eq(read(fd, buffer, 4), 0);
+	igt_assert_eq(read(fd, buffer, 4), -1);
+	igt_assert_eq(errno, EAGAIN);
 	igt_assert(read(fd, buffer, 40) > 0);
 	igt_assert(read(fd, buffer, 40) > 0);
 
-- 
1.7.9.5