[igt-dev] [PATCH i-g-t] i915/gem_exec_capture: Trim the blocking workload

[Chris Wilson]

While we want the capture to last long enough to delay the concurrent
client, we don't want to wait forever for the capture to complete to
proceed with the testing.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2559
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 tests/i915/gem_exec_capture.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tests/i915/gem_exec_capture.c b/tests/i915/gem_exec_capture.c
index cb0d3151b..3da78d632 100644
--- a/tests/i915/gem_exec_capture.c
+++ b/tests/i915/gem_exec_capture.c
@@ -21,6 +21,7 @@
  * IN THE SOFTWARE.
  */
 
+#include <sys/poll.h>
 #include <zlib.h>
 
 #include "i915/gem.h"
@@ -524,6 +525,7 @@ static void prioinv(int fd, int dir, unsigned ring, const char *name)
 		  gtt, ram);
 
 	count = min(gtt, ram) / 4;
+	count = min(count, 256); /* Keep the duration within reason */
 	igt_require(count > 1);
 
 	intel_require_memory(count, size, CHECK_RAM);
@@ -535,18 +537,26 @@ static void prioinv(int fd, int dir, unsigned ring, const char *name)
 	igt_assert(pipe(link) == 0);
 	igt_fork(child, 1) {
 		fd = gem_reopen_driver(fd);
-		igt_debug("Submitting large hang + capture\n");
+		igt_debug("Submitting large capture [%ld x %dMiB objects]\n",
+			  count, (int)(size >> 20));
 		free(__captureN(fd, dir, ring, size, count, ASYNC));
 		write(link[1], &fd, sizeof(fd)); /* wake the parent up */
 		igt_force_gpu_reset(fd);
+		write(link[1], &fd, sizeof(fd)); /* wake the parent up */
 	}
 	read(link[0], &dummy, sizeof(dummy));
+	igt_require_f(poll(&(struct pollfd){link[0], POLLIN}, 1, 500) == 0,
+		      "Capture completed too quickly! Will not block\n");
 
 	igt_debug("Submitting nop\n");
 	gem_execbuf(fd, &execbuf);
 	igt_assert_eq(gem_wait(fd, obj.handle, &timeout), 0);
 	gem_close(fd, obj.handle);
 
+	igt_assert_f(poll(&(struct pollfd){link[0], POLLIN}, 1, 0) == 0,
+		     "Capture completed before nop!\n");
+
+	igt_debug("Waiting for capture/reset to complete\n");
 	igt_waitchildren();
 	close(link[0]);
 	close(link[1]);
-- 
2.29.2