[igt-dev] [PATCH i-g-t] lib/igt_kms: Reset FIFO underruns on first commit after init()/reset().

[Maarten Lankhorst]

When we set the test to its first state, we will clear FIFO underrun
status through the debugfs, so that any underruns caused by the tests
will not affect other tests. In particular this also resets the FBC
FIFO underrun status, so previous failures won't affect other tests
that depend on FBC.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105681
---
 lib/igt_kms.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 19d650a8dcf8..c943411e52d7 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -3112,6 +3112,13 @@ display_commit_changed(igt_display_t *display, enum igt_commit_style s)
 	}
 
 	if (display->first_commit) {
+		int fd = igt_debugfs_open(display->drm_fd, "i915_fifo_underrun_reset", O_WRONLY);
+		if (fd >= 0) {
+			igt_assert_eq(write(fd, "y", 1), 1);
+
+			close(fd);
+		}
+
 		igt_display_drop_events(display);
 		display->first_commit = false;
 	}
-- 
2.16.3