[Intel-gfx] [PATCH igt 2/4] lib: Idle the GT when quiescing the GPU

[Chris Wilson]

As part of the general procedure for ensuring the GPU is idle, we also
want to ask the driver to flush its idle_worker. The idle_worker is
responsible for releasing both the driver's internal cache of buffers
and cache of state (such as the prolonged GT wakeref). By flushing the
idle_worker we ensure that each test (each caller needing an idle gpu)
has a clean slate; not carrying over caches from one test to the next.

Note this is a silent no-op for kernels that do not know about DROP_IDLE,
old bugs will remain.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 lib/drmtest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/drmtest.c b/lib/drmtest.c
index 8a07152c..15a46477 100644
--- a/lib/drmtest.c
+++ b/lib/drmtest.c
@@ -187,7 +187,7 @@ void gem_quiescent_gpu(int fd)
 	gem_sync(fd, obj.handle);
 	gem_close(fd, obj.handle);
 
-	igt_drop_caches_set(fd, DROP_RETIRE | DROP_FREED);
+	igt_drop_caches_set(fd, DROP_RETIRE | DROP_IDLE | DROP_FREED);
 }
 
 /**
-- 
2.15.0.rc1