[Mesa-dev] [PATCH 4/6] isl: Let isl_surf_init's caller set the exact row pitch

[Jason Ekstrand]

On Mon, Mar 6, 2017 at 10:12 AM, Chad Versace <chadversary at chromium.org>
wrote:

> The caller does so by setting the new field
> isl_surf_init_info::row_pitch, which overrides isl's row pitch
> calculation.
> ---
>  src/intel/isl/isl.c | 11 ++++++++++-
>  src/intel/isl/isl.h |  9 +++++++++
>  2 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/src/intel/isl/isl.c b/src/intel/isl/isl.c
> index a91c3f92bcf..b3ac305b81b 100644
> --- a/src/intel/isl/isl.c
> +++ b/src/intel/isl/isl.c
> @@ -1005,6 +1005,9 @@ isl_calc_linear_row_pitch(const struct isl_device
> *dev,
>  {
>     const struct isl_format_layout *fmtl = isl_format_get_layout(info->
> format);
>
> +   /* Any override of row_pitch should happen earlier. */
> +   assert(info->row_pitch == 0);
> +
>     uint32_t row_pitch = info->min_row_pitch;
>
>     /* First, align the surface to a cache line boundary, as the PRM
> explains
> @@ -1088,6 +1091,9 @@ isl_calc_tiled_row_pitch(const struct isl_device
> *dev,
>  {
>     const struct isl_format_layout *fmtl = isl_format_get_layout(info->
> format);
>
> +   /* Any override of row_pitch should happen earlier. */
> +   assert(info->row_pitch == 0);
> +
>     assert(fmtl->bpb % tile_info->format_bpb == 0);
>     assert(phys_slice0_sa->w % fmtl->bw == 0);
>
> @@ -1112,7 +1118,10 @@ isl_calc_row_pitch(const struct isl_device *dev,
>                     const struct isl_tile_info *tile_info,
>                     const struct isl_extent2d *phys_slice0_sa)
>  {
> -   if (tile_info->tiling == ISL_TILING_LINEAR) {
> +   if (info->row_pitch != 0) {
> +      /* Override the usual calculation and validation. */
> +      return info->row_pitch;
> +   } else if (tile_info->tiling == ISL_TILING_LINEAR) {
>        return isl_calc_linear_row_pitch(dev, info, phys_slice0_sa);
>     } else {
>        return isl_calc_tiled_row_pitch(dev, info, tile_info,
> phys_slice0_sa);
> diff --git a/src/intel/isl/isl.h b/src/intel/isl/isl.h
> index e517f11cf5e..5f73639fb48 100644
> --- a/src/intel/isl/isl.h
> +++ b/src/intel/isl/isl.h
> @@ -813,6 +813,15 @@ struct isl_surf_init_info {
>     /** Lower bound for isl_surf::row_pitch, in bytes. */
>     uint32_t min_row_pitch;
>
> +   /**
> +    * Exact value for isl_surf::row_pitch. Ignored if zero.
> +    *
> +    * WARNING: If set, then isl_surf_init() skips many calculations and
> +    * validations. If the given row pitch is incompatible with the
> requested
> +    * surface, then behavior is undefined.
>

I'm not a fan.  I would much rather supplying a row_pitch mean "please
validate and use this" rather than "trust me".  I don't want isl_surf_init
to succeed and still give you a bad surface.  Sorry if that means real
work. :-/


> +    */
> +   uint32_t row_pitch;
> +
>     isl_surf_usage_flags_t usage;
>
>     /** Flags that alter how ISL selects isl_surf::tiling.  */
> --
> 2.12.0
>
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>
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