[igt-dev] [PATCH i-g-t v2 5/5] lib/igt_fb: Fix blitter limit checks

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

The earlier approach of checking the higher tiled stride
limit has backfired. All out blits are between tiled and
linear, but we only ever check this for the tiled fb. Thus
we are taking the blitter path even though the linear fb
exceeds the blitter limits. So let's just check the limits
as if we are operating on linear fbs.

And let's toss in some width/height checks, and let's do
the checks for all the color planes as well.

v2: Reword the comment a bit to hopefully make it legible (Chris)

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 lib/igt_fb.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/lib/igt_fb.c b/lib/igt_fb.c
index 292c19d28c1a..8664d1af6f31 100644
--- a/lib/igt_fb.c
+++ b/lib/igt_fb.c
@@ -1580,29 +1580,37 @@ struct fb_blit_upload {
 	struct intel_batchbuffer *batch;
 };
 
-static int max_blitter_stride(int fd, uint64_t modifier)
+static bool blitter_ok(const struct igt_fb *fb)
 {
-	int stride = 32768;
-
-	if (intel_gen(intel_get_drm_devid(fd)) >= 4 &&
-	    modifier != DRM_FORMAT_MOD_NONE)
-		stride *= 4;
+	for (int i = 0; i < fb->num_planes; i++) {
+		/*
+		 * gen4+ stride limit is 4x this with tiling,
+		 * but since our blits are always between tiled
+		 * and linear surfaces (and we do this check just
+		 * for the tiled surface) we must use the lower
+		 * linear stride limit here.
+		 */
+		if (fb->plane_width[i] > 32767 ||
+		    fb->plane_height[i] > 32767 ||
+		    fb->strides[i] > 32767)
+			return false;
+	}
 
-	return stride;
+	return true;
 }
 
 static bool use_rendercopy(const struct igt_fb *fb)
 {
 	return is_ccs_modifier(fb->modifier) ||
 		(fb->modifier == I915_FORMAT_MOD_Yf_TILED &&
-		 fb->strides[0] >= max_blitter_stride(fb->fd, fb->modifier));
+		 !blitter_ok(fb));
 }
 
 static bool use_blitter(const struct igt_fb *fb)
 {
 	return (fb->modifier == I915_FORMAT_MOD_Y_TILED ||
 		fb->modifier == I915_FORMAT_MOD_Yf_TILED) &&
-		fb->strides[0] < max_blitter_stride(fb->fd, fb->modifier);
+		blitter_ok(fb);
 }
 
 static void init_buf(struct fb_blit_upload *blit,
-- 
2.21.0