[Intel-gfx] [RESEND PATCH v6 i-g-t] tests/kms_flip: Skip VBlank tests in modules without VBlank

[Rodrigo Siqueira]

The kms_flip test relies on VBlank support, and this situation may
exclude some virtual drivers to take advantage of this set of tests.
This commit adds a mechanism that checks if a module has VBlank. If the
target module has VBlank support, kms_flip will run all the VBlank
tests; otherwise, the VBlank tests will be skipped. Additionally, this
commit improves the test coverage by checks if the function
drmWaitVBlank() returns EOPNOTSUPP (i.e., no VBlank support).

V5: Drop the DRM_VBLANK_NEXTONMISS (Chris Wilson)

V4: Replace DRM_VBLANK_ABSOLUTE by DRM_VBLANK_RELATIVE and
DRM_VBLANK_NEXTONMISS

V3: Add documentation (Daniel Vetter)

V2: Add new branch coverage to check if VBlank is enabled or not and
update commit message

V1: Chris Wilson
  - Change function name from igt_there_is_vblank to kms_has_vblank
  - Move vblank function check from igt_aux to igt_kms
  - Utilizes memset in dummy_vbl variable
  - Directly return the result of drmWaitVBlank()

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
---
Updates:
1. Rebase the code with the last updates from the master.
2. Patch tested on VC4, Bochs, VKMS, and i915.

 lib/igt_kms.c    | 20 ++++++++++++++++++++
 lib/igt_kms.h    |  2 ++
 tests/kms_flip.c | 22 ++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index df9aafd2..0bdd1e40 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -1656,6 +1656,26 @@ void igt_assert_plane_visible(int fd, enum pipe pipe, int plane_index, bool visi
 	igt_assert_eq(visible, visibility);
 }
 
+/**
+ * kms_has_vblank:
+ * @fd: DRM fd
+ *
+ * Get the VBlank errno after an attempt to call drmWaitVBlank(). This
+ * function is useful for checking if a driver has support or not for VBlank.
+ *
+ * Returns: true if target driver has VBlank support, otherwise return false.
+ */
+bool kms_has_vblank(int fd)
+{
+	drmVBlank dummy_vbl;
+
+	memset(&dummy_vbl, 0, sizeof(drmVBlank));
+	dummy_vbl.request.type = DRM_VBLANK_RELATIVE;
+
+	drmWaitVBlank(fd, &dummy_vbl);
+	return (errno != EOPNOTSUPP);
+}
+
 /*
  * A small modeset API
  */
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 38bdc08f..b0ff79ab 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -230,6 +230,8 @@ void kmstest_wait_for_pageflip(int fd);
 unsigned int kmstest_get_vblank(int fd, int pipe, unsigned int flags);
 void igt_assert_plane_visible(int fd, enum pipe pipe, int plane_index, bool visibility);
 
+bool kms_has_vblank(int fd);
+
 /*
  * A small modeset API
  */
diff --git a/tests/kms_flip.c b/tests/kms_flip.c
index 6287ce14..4e0471a9 100755
--- a/tests/kms_flip.c
+++ b/tests/kms_flip.c
@@ -71,6 +71,7 @@
 #define TEST_SUSPEND		(1 << 26)
 #define TEST_BO_TOOBIG		(1 << 28)
 
+#define TEST_NO_VBLANK		(1 << 29)
 #define TEST_BASIC		(1 << 30)
 
 #define EVENT_FLIP		(1 << 0)
@@ -126,6 +127,18 @@ struct event_state {
 	int seq_step;
 };
 
+static bool vblank_dependence(int flags)
+{
+	int vblank_flags = TEST_VBLANK | TEST_VBLANK_BLOCK |
+			   TEST_VBLANK_ABSOLUTE | TEST_VBLANK_EXPIRED_SEQ |
+			   TEST_CHECK_TS | TEST_VBLANK_RACE;
+
+	if (flags & vblank_flags)
+		return true;
+
+	return false;
+}
+
 static float timeval_float(const struct timeval *tv)
 {
 	return tv->tv_sec + tv->tv_usec / 1000000.0f;
@@ -1176,6 +1189,7 @@ static void run_test_on_crtc_set(struct test_output *o, int *crtc_idxs,
 	unsigned bo_size = 0;
 	uint64_t tiling;
 	int i;
+	bool vblank = true;
 
 	switch (crtc_count) {
 	case RUN_TEST:
@@ -1259,6 +1273,14 @@ static void run_test_on_crtc_set(struct test_output *o, int *crtc_idxs,
 	}
 	igt_assert(fb_is_bound(o, o->fb_ids[0]));
 
+	vblank = kms_has_vblank(drm_fd);
+	if (!vblank) {
+		if (vblank_dependence(o->flags))
+			igt_require_f(vblank, "There is no VBlank\n");
+		else
+			o->flags |= TEST_NO_VBLANK;
+	}
+
 	/* quiescent the hw a bit so ensure we don't miss a single frame */
 	if (o->flags & TEST_CHECK_TS)
 		calibrate_ts(o, crtc_idxs[0]);
-- 
2.21.0