[Mesa-dev] [PATCH 05/12] i965/vec4/skl+: Use lcd2dms_w instead of lcd2dms

[Ben Widawsky]

On Thu, Sep 17, 2015 at 05:00:07PM +0100, Neil Roberts wrote:
> In order to support 16x MSAA, skl+ has a wider version of lcd2dms that
> takes two parameters for the MCS data. The MCS data in the response
> still fits in a single register so we just need to ensure we copy both
> values rather than just the lower one.
> ---
>  src/mesa/drivers/dri/i965/brw_vec4.cpp           |  1 +
>  src/mesa/drivers/dri/i965/brw_vec4_generator.cpp |  5 +++++
>  src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp   | 14 ++++++++++++--
>  3 files changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
> index ed49cd3..22c8d01 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
> @@ -327,6 +327,7 @@ vec4_visitor::implied_mrf_writes(vec4_instruction *inst)
>     case SHADER_OPCODE_TXD:
>     case SHADER_OPCODE_TXF:
>     case SHADER_OPCODE_TXF_CMS:
> +   case SHADER_OPCODE_TXF_CMS_W:
>     case SHADER_OPCODE_TXF_MCS:
>     case SHADER_OPCODE_TXS:
>     case SHADER_OPCODE_TG4:
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
> index 1950333..c4ddff9 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
> @@ -259,6 +259,10 @@ vec4_generator::generate_tex(vec4_instruction *inst,
>        case SHADER_OPCODE_TXF:
>  	 msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LD;
>  	 break;
> +      case SHADER_OPCODE_TXF_CMS_W:
> +         assert(devinfo->gen >= 9);
> +         msg_type = GEN9_SAMPLER_MESSAGE_SAMPLE_LD2DMS_W;
> +         break;
>        case SHADER_OPCODE_TXF_CMS:
>           if (devinfo->gen >= 7)
>              msg_type = GEN7_SAMPLER_MESSAGE_SAMPLE_LD2DMS;
> @@ -1372,6 +1376,7 @@ vec4_generator::generate_code(const cfg_t *cfg)
>        case SHADER_OPCODE_TXD:
>        case SHADER_OPCODE_TXF:
>        case SHADER_OPCODE_TXF_CMS:
> +      case SHADER_OPCODE_TXF_CMS_W:
>        case SHADER_OPCODE_TXF_MCS:
>        case SHADER_OPCODE_TXL:
>        case SHADER_OPCODE_TXS:
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
> index 0465770..79f92d8 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
> @@ -2545,7 +2545,8 @@ vec4_visitor::emit_texture(ir_texture_opcode op,
>     case ir_txl: opcode = SHADER_OPCODE_TXL; break;
>     case ir_txd: opcode = SHADER_OPCODE_TXD; break;
>     case ir_txf: opcode = SHADER_OPCODE_TXF; break;
> -   case ir_txf_ms: opcode = SHADER_OPCODE_TXF_CMS; break;
> +   case ir_txf_ms: opcode = (devinfo->gen >= 9 ? SHADER_OPCODE_TXF_CMS_W :
> +                             SHADER_OPCODE_TXF_CMS); break;
>     case ir_txs: opcode = SHADER_OPCODE_TXS; break;
>     case ir_tg4: opcode = offset_value.file != BAD_FILE
>                           ? SHADER_OPCODE_TG4_OFFSET : SHADER_OPCODE_TG4; break;
> @@ -2637,7 +2638,16 @@ vec4_visitor::emit_texture(ir_texture_opcode op,
>        } else if (op == ir_txf_ms) {
>           emit(MOV(dst_reg(MRF, param_base + 1, sample_index.type, WRITEMASK_X),
>                    sample_index));
> -         if (devinfo->gen >= 7) {
> +         if (opcode == SHADER_OPCODE_TXF_CMS_W) {
> +            /* MCS data is stored in the first two channels of ‘mcs’, but we
> +             * need to get it into the .y and .z channels of the second vec4
> +             * of params.
> +             */

I don't understand what you mean by the "second vec4". Do you just mean the .y
and .z channel?

> +            mcs.swizzle = BRW_SWIZZLE4(0, 0, 1, 1);

I don't really understand how the swizzle stuff works. Quick explanation on why
it's not BRW_SWIZZLE_XYXY would be greatly appreciated.

> +            emit(MOV(dst_reg(MRF, param_base + 1,
> +                             glsl_type::uint_type, WRITEMASK_YZ),
> +                     mcs));
> +         } else if (devinfo->gen >= 7) {
>              /* MCS data is in the first channel of `mcs`, but we need to get it into
>               * the .y channel of the second vec4 of params, so replicate .x across
>               * the whole vec4 and then mask off everything except .y