[igt-dev] [PATCH i-g-t] lib/crc: Reset fifo underrun reporting for every crc capture

[Daniel Vetter]

We have tons of issues with crc mismatches, but often by that time
there was already a fifo underrun, which disables further fifo
underrun reporting. Reset fifo underrun reporting before we capture a
crc so that it's easier to figure out why the crc mismatch happened.

Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 lib/igt_debugfs.c | 21 +++++++++++++++++++++
 lib/igt_debugfs.h |  2 ++
 lib/igt_kms.c     |  8 ++------
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c
index 6cfaa97579e7..640c78e972e9 100644
--- a/lib/igt_debugfs.c
+++ b/lib/igt_debugfs.c
@@ -808,6 +808,8 @@ void igt_pipe_crc_start(igt_pipe_crc_t *pipe_crc)
 	/* Stop first just to make sure we don't have lingering state left. */
 	igt_pipe_crc_stop(pipe_crc);
 
+	igt_reset_fifo_underrun_reporting(pipe_crc->fd);
+
 	igt_assert_eq(write(pipe_crc->ctl_fd, src, strlen(src)), strlen(src));
 
 	sprintf(buf, "crtc-%d/crc/data", pipe_crc->pipe);
@@ -1002,6 +1004,25 @@ void igt_pipe_crc_collect_crc(igt_pipe_crc_t *pipe_crc, igt_crc_t *out_crc)
 	igt_pipe_crc_stop(pipe_crc);
 }
 
+/**
+ * igt_reset_fifo_underrun_reporting:
+ * @drm_fd: drm device file descriptor
+ *
+ * Resets fifo underrun reporting, if supported by the device. Useful since fifo
+ * underrun reporting tends to be one-shot, so good to reset it before the
+ * actual functional test again in case there's been a separate issue happening
+ * while preparing the test setup.
+ */
+void igt_reset_fifo_underrun_reporting(int drm_fd)
+{
+	int fd = igt_debugfs_open(drm_fd, "i915_fifo_underrun_reset", O_WRONLY);
+	if (fd >= 0) {
+		igt_assert_eq(write(fd, "y", 1), 1);
+
+		close(fd);
+	}
+}
+
 /*
  * Drop caches
  */
diff --git a/lib/igt_debugfs.h b/lib/igt_debugfs.h
index 1233cd8f7a07..b9cf0f813773 100644
--- a/lib/igt_debugfs.h
+++ b/lib/igt_debugfs.h
@@ -216,6 +216,8 @@ void igt_require_hpd_storm_ctl(int fd);
 		  DROP_FREED | \
 		  DROP_IDLE)
 
+void igt_reset_fifo_underrun_reporting(int drm_fd);
+
 bool igt_drop_caches_has(int fd, uint64_t val);
 void igt_drop_caches_set(int fd, uint64_t val);
 
diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 85a911e11060..080f90ae6e8c 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -3269,14 +3269,10 @@ 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_reset_fifo_underrun_reporting(display->drm_fd);
 
 		igt_display_drop_events(display);
+
 		display->first_commit = false;
 	}
 }
-- 
2.20.1