On Mon, Jan 16, 2017 at 1:13 AM, Topi Pohjolainen <
topi.pohjolai...@gmail.com> wrote:
> Gen8 and Gen9 are already more heavily constrained as one
> applies arrayed/mipmapped alignment even for non-arrayed and
> non-mipmapped.
>
> Signed-off-by: Topi Pohjolainen <topi.pohjolai...@intel.com>
> ---
> src/intel/isl/isl_gen7.c | 39 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/src/intel/isl/isl_gen7.c b/src/intel/isl/isl_gen7.c
> index 18687b5..b1874c1 100644
> --- a/src/intel/isl/isl_gen7.c
> +++ b/src/intel/isl/isl_gen7.c
> @@ -403,6 +403,45 @@ isl_gen7_choose_image_alignment_el(const struct
> isl_device *dev,
> /* IVB+ does not support combined depthstencil. */
> assert(!isl_surf_usage_is_depth_and_stencil(info->usage));
>
> + const struct isl_format_layout *fmtl = isl_format_get_layout(info->
> format);
> + if (fmtl->txc == ISL_TXC_CCS) {
> + assert(tiling == ISL_TILING_CCS);
> +
> + /*
> + * IvyBrigde PRM Vol 2, Part 1, "11.7 MCS Buffer for Render
> Target(s)":
> + *
> + * The following table describes the RT alignment
> + * Pixels Lines
> + * TiledY RT CL
> + * bpp
> + * 32 8 4
> + * 64 4 4
> + * 128 2 4
> + */
>
This isn't quite correct... Yes, the table above describes the horizontal
and vertical alignment of the single-sampled MCS on Ivy Bridge. However,
ISL already takes care of this for us by its choice of block sizes. Each
of the CCS formats is a "compressed" format with a block size that exactly
matches the alignment given in the table. Since the alignment returned by
this function is in units of *elements*, the correct value should be 1x1
for all CCS formats on gen7. For instance, GEN7_CCS_32BPP_Y is a
compressed format with a block size of 8x4 pixels per element and a 1x1el
alignment becomes 8x4px. Does that make sense? It's a bit subtle.
> + switch (fmtl->format) {
> + case ISL_FORMAT_GEN7_CCS_32BPP_X:
> + *image_align_el = isl_extent3d(8, 4, 1);
> + return;
> + case ISL_FORMAT_GEN7_CCS_64BPP_X:
> + *image_align_el = isl_extent3d(4, 4, 1);
> + return;
> + case ISL_FORMAT_GEN7_CCS_128BPP_X:
> + *image_align_el = isl_extent3d(2, 4, 1);
> + return;
> + case ISL_FORMAT_GEN7_CCS_32BPP_Y:
> + *image_align_el = isl_extent3d(8, 4, 1);
> + return;
> + case ISL_FORMAT_GEN7_CCS_64BPP_Y:
> + *image_align_el = isl_extent3d(4, 4, 1);
> + return;
> + case ISL_FORMAT_GEN7_CCS_128BPP_Y:
> + *image_align_el = isl_extent3d(2, 4, 1);
> + return;
> + default:
> + unreachable("Invalid CCS format");
> + }
> + }
> +
> *image_align_el = (struct isl_extent3d) {
> .w = gen7_choose_halign_el(dev, info),
> .h = gen7_choose_valign_el(dev, info, tiling),
> --
> 2.5.5
>
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