[Intel-gfx] [PATCH] tests/kms_flip: test a fb backed by a bo too big for its own good

[oscar.mateo at intel.com]

From: Oscar Mateo <oscar.mateo at intel.com>

This is a "review by igt test" for a bug located in
i915_gem_object_pin_to_display_plane and fixed by:

commit 392013bdd4b6128795e33c84bd6d6d3fd66ff0a3
Author: Oscar Mateo <oscar.mateo at intel.com>
Date:   Fri May 16 11:23:12 2014 +0100

    drm/i915: Gracefully handle obj not bound to GGTT in is_pin_display

    Otherwise, we do a NULL pointer dereference.

    I've seen this happen while handling an error in
    i915_gem_object_pin_to_display_plane():

    If i915_gem_object_set_cache_level() fails, we call is_pin_display()
    to handle the error. At this point, the object is still not pinned
    to GGTT and maybe not even bound, so we have to check before we
    dereference its GGTT vma.

    v2: Chris Wilson says restoring the old value is easier, but that
    is_pin_display is useful as a theory of operation. Take the solomonic
    decision: at least this way is_pin_display is a little more robust
    (until Chris can kill it off).

Signed-off-by: Oscar Mateo <oscar.mateo at intel.com>
---
 tests/kms_flip.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 97 insertions(+), 5 deletions(-)

diff --git a/tests/kms_flip.c b/tests/kms_flip.c
index bb4f71d..7296122 100644
--- a/tests/kms_flip.c
+++ b/tests/kms_flip.c
@@ -74,6 +74,7 @@
 #define TEST_RPM		(1 << 25)
 #define TEST_SUSPEND		(1 << 26)
 #define TEST_TS_CONT		(1 << 27)
+#define TEST_BO_TOOBIG		(1 << 28)
 
 #define EVENT_FLIP		(1 << 0)
 #define EVENT_VBLANK		(1 << 1)
@@ -1208,6 +1209,84 @@ static void free_test_output(struct test_output *o)
 	}
 }
 
+static int create_bigbo_for_fb(int fd, int width, int height, int bpp,
+				   bool tiled, uint32_t *gem_handle_ret,
+				   unsigned *size_ret, unsigned *stride_ret)
+{
+	uint32_t gem_handle;
+	int size, ret = 0;
+	unsigned stride;
+
+	if (tiled) {
+		int v;
+
+		v = width * bpp / 8;
+		for (stride = 512; stride < v; stride *= 2)
+			;
+
+		v = stride * height;
+		for (size = 1024*1024; size < v; size *= 2)
+			;
+	} else {
+		/* Scan-out has a 64 byte alignment restriction */
+		stride = (width * (bpp / 8) + 63) & ~63;
+		size = stride * height;
+	}
+
+	/* 256 MB is usually the maximum mappable aperture,
+	 * (make it 4x times that to ensure failure) */
+	gem_handle = gem_create(fd, 4*256*1024*1024);
+
+	if (tiled)
+		ret = __gem_set_tiling(fd, gem_handle, I915_TILING_X, stride);
+
+	*stride_ret = stride;
+	*size_ret = size;
+	*gem_handle_ret = gem_handle;
+
+	return ret;
+}
+
+static unsigned int igt_create_fb_with_bigbo(int fd, int width, int height,
+					     uint32_t format, bool tiled,
+					     struct igt_fb *fb)
+{
+	uint32_t handles[4];
+	uint32_t pitches[4];
+	uint32_t offsets[4];
+	uint32_t fb_id;
+	int bpp;
+	int ret;
+
+	memset(fb, 0, sizeof(*fb));
+
+	bpp = igt_drm_format_to_bpp(format);
+	ret = create_bigbo_for_fb(fd, width, height, bpp, tiled,
+			&fb->gem_handle, &fb->size, &fb->stride);
+	if (ret < 0)
+		return ret;
+
+	memset(handles, 0, sizeof(handles));
+	handles[0] = fb->gem_handle;
+	memset(pitches, 0, sizeof(pitches));
+	pitches[0] = fb->stride;
+	memset(offsets, 0, sizeof(offsets));
+	if (drmModeAddFB2(fd, width, height, format, handles, pitches,
+			  offsets, &fb_id, 0) < 0) {
+		gem_close(fd, fb->gem_handle);
+
+		return 0;
+	}
+
+	fb->width = width;
+	fb->height = height;
+	fb->tiling = tiled;
+	fb->drm_format = format;
+	fb->fb_id = fb_id;
+
+	return fb_id;
+}
+
 static void run_test_on_crtc_set(struct test_output *o, int *crtc_idxs,
 				 int crtc_count, int duration_ms)
 {
@@ -1252,9 +1331,15 @@ static void run_test_on_crtc_set(struct test_output *o, int *crtc_idxs,
 	o->fb_ids[0] = igt_create_fb(drm_fd, o->fb_width, o->fb_height,
 					 igt_bpp_depth_to_drm_format(o->bpp, o->depth),
 					 tiled, &o->fb_info[0]);
-	o->fb_ids[1] = igt_create_fb(drm_fd, o->fb_width, o->fb_height,
-					 igt_bpp_depth_to_drm_format(o->bpp, o->depth),
-					 tiled, &o->fb_info[1]);
+	if (o->flags & TEST_BO_TOOBIG) {
+		o->fb_ids[1] = igt_create_fb_with_bigbo(drm_fd, o->fb_width, o->fb_height,
+						 igt_bpp_depth_to_drm_format(o->bpp, o->depth),
+						 tiled, &o->fb_info[1]);
+	} else {
+		o->fb_ids[1] = igt_create_fb(drm_fd, o->fb_width, o->fb_height,
+						 igt_bpp_depth_to_drm_format(o->bpp, o->depth),
+						 tiled, &o->fb_info[1]);
+	}
 	o->fb_ids[2] = igt_create_fb(drm_fd, o->fb_width, o->fb_height,
 					 igt_bpp_depth_to_drm_format(o->bpp, o->depth),
 					 true, &o->fb_info[2]);
@@ -1264,7 +1349,8 @@ static void run_test_on_crtc_set(struct test_output *o, int *crtc_idxs,
 		igt_require(o->fb_ids[2]);
 
 	paint_flip_mode(&o->fb_info[0], false);
-	paint_flip_mode(&o->fb_info[1], true);
+	if (!(o->flags & TEST_BO_TOOBIG))
+		paint_flip_mode(&o->fb_info[1], true);
 	if (o->fb_ids[2])
 		paint_flip_mode(&o->fb_info[2], true);
 
@@ -1288,10 +1374,15 @@ static void run_test_on_crtc_set(struct test_output *o, int *crtc_idxs,
 	if (o->flags & TEST_CHECK_TS)
 		sleep(1);
 
-	igt_assert(do_page_flip(o, o->fb_ids[1], true) == 0);
+	if (o->flags & TEST_BO_TOOBIG) {
+		igt_assert(do_page_flip(o, o->fb_ids[1], true) == -E2BIG);
+		goto out;
+	} else
+		igt_assert(do_page_flip(o, o->fb_ids[1], true) == 0);
 	wait_for_events(o);
 
 	o->current_fb_id = 1;
+
 	if (o->flags & TEST_FLIP)
 		o->flip_state.seq_step = 1;
 	else
@@ -1543,6 +1634,7 @@ int main(int argc, char **argv)
 		{ 10, TEST_VBLANK | TEST_DPMS | TEST_SUSPEND | TEST_TS_CONT, "dpms-vs-suspend" },
 		{ 0, TEST_VBLANK | TEST_MODESET | TEST_RPM | TEST_TS_CONT, "modeset-vs-rpm" },
 		{ 0, TEST_VBLANK | TEST_MODESET | TEST_SUSPEND | TEST_TS_CONT, "modeset-vs-suspend" },
+		{ 0, TEST_BO_TOOBIG | TEST_NO_2X_OUTPUT, "bo-too-big" },
 	};
 	int i;
 
-- 
1.9.0