minigbm: conditionally fallback to strip scanout use_flag

Only 2d virtgpu backend needs to fallback here because virtio primary
plane only allows DRM_FORMAT_XRGB8888.

Most our platforms cannot display YV12 (except msm), thus the fallback
is required for the converted DRM_FORMAT_YVU420_ANDROID. For virgl
backend, additionally append a BO_USE_LINEAR as a replacement for the
hack inside compute_virgl_bind_flags.

BUG=b:199524294
TEST=CQ
TEST=gralloctest alloc_combinations
TEST=android.media.cts.VideoDecoderRotationTest

Change-Id: Ic87838ea2aae2b0abf87ed898ad75a3d7e556471
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/3166775
Tested-by: Yiwei Zhang <zzyiwei@chromium.org>
Auto-Submit: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Commit-Queue: Yiwei Zhang <zzyiwei@chromium.org>
diff --git a/helpers.c b/helpers.c
index 3c720cc..4c76e07 100644
--- a/helpers.c
+++ b/helpers.c
@@ -665,3 +665,11 @@
 		return format;
 	}
 }
+
+uint64_t drv_resolve_use_flags_helper(uint32_t format, uint64_t use_flags)
+{
+	if (format == DRM_FORMAT_YVU420_ANDROID)
+		return use_flags & ~BO_USE_SCANOUT;
+
+	return use_flags;
+}