[Intel-gfx] [PATCH igt] igt/gem_mocs_settings: Wait for RC6 EI before polling

[Chris Wilson]

On bxt, we see that the rc6 subtest flip-flops as RC6 does not restart
within our desired interval. Improve the likelihood of the inspection
passing by idling the GPU and waiting for 2 Evaluation Intervals before
we start polling of RC6 residency.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 tests/gem_mocs_settings.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/gem_mocs_settings.c b/tests/gem_mocs_settings.c
index 9705fbfd..85fd637a 100644
--- a/tests/gem_mocs_settings.c
+++ b/tests/gem_mocs_settings.c
@@ -336,12 +336,15 @@ static uint32_t rc6_residency(int dir)
 
 static void rc6_wait(int fd)
 {
-	int sysfs;
 	uint32_t residency;
+	int sysfs;
 
 	sysfs = igt_sysfs_open(fd, NULL);
 	igt_assert_lte(0, sysfs);
 
+	gem_quiescent_gpu(fd);
+	usleep(320e3); /* Wait for 2 EIs before polling; should now be active */
+
 	residency = rc6_residency(sysfs);
 	igt_require(igt_wait(rc6_residency(sysfs) != residency, 10000, 2));
 
-- 
2.16.2