Re: [PATCH 3/3] drm/vc4: Prefer PPF over TPZ when dst >= 2/3 src

Boris Brezillon boris.brezillon@bootlin.com writes:

The HVS spec recommends using PPF when the downscaling ratio is between 2/3 and 1. Let's modify vc4_get_scaling_mode() to follow this recommendation.

Signed-off-by: Boris Brezillon boris.brezillon@bootlin.com

drivers/gpu/drm/vc4/vc4_plane.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c index 5950e6b6b7f0..1d0d91e50aaf 100644 --- a/drivers/gpu/drm/vc4/vc4_plane.c +++ b/drivers/gpu/drm/vc4/vc4_plane.c @@ -129,12 +129,12 @@ static const struct hvs_format *vc4_get_hvs_format(u32 drm_format)

static enum vc4_scaling_mode vc4_get_scaling_mode(u32 src, u32 dst) {

• if (dst > src)

• if (dst == src)

• return VC4_SCALING_NONE;
  

• if (3 * dst >= 2 * src) return VC4_SCALING_PPF;

• else if (dst < src)

• return VC4_SCALING_TPZ;
  

  else

• return VC4_SCALING_NONE;
  

• return VC4_SCALING_TPZ;
  

}

Reviewed-by: Eric Anholt eric@anholt.net