[Intel-gfx] [PATCH] drm/i915: Add the predicate source registers to the register whitelist

[Volkin, Bradley D]

On Fri, Nov 07, 2014 at 07:34:31AM -0800, Neil Roberts wrote:
> The predicate source registers are needed to implement conditional
> rendering without stalling. The two source registers are used to load
> the previous values of the PS_DEPTH_COUNT register saved from
> PIPE_CONTROL commands. These can then be compared and used to set the
> predicate enable bit via the MI_PREDICATE command.
> 
> Signed-off-by: Neil Roberts <neil at linux.intel.com>

Reviewed-by: Brad Volkin <bradley.d.volkin at intel.com>

> ---
> 
> There is a corresponding patch for Mesa which is using these registers
> on the mailing list here:
> 
> http://lists.freedesktop.org/archives/mesa-dev/2014-November/070347.html
> 
> There are some other registers such as MI_PREDICATE_DATA which can be
> used for more advanced predicate checking but I haven't added them to
> the list because they aren't needed to implement
> GL_NV_conditional_render.
> 
>  drivers/gpu/drm/i915/i915_cmd_parser.c | 2 ++
>  drivers/gpu/drm/i915/i915_reg.h        | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
> index 4c35e2a..9732155 100644
> --- a/drivers/gpu/drm/i915/i915_cmd_parser.c
> +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
> @@ -408,6 +408,8 @@ static const u32 gen7_render_regs[] = {
>  	REG64(PS_INVOCATION_COUNT),
>  	REG64(PS_DEPTH_COUNT),
>  	OACONTROL, /* Only allowed for LRI and SRM. See below. */
> +	REG64(MI_PREDICATE_SRC0),
> +	REG64(MI_PREDICATE_SRC1),
>  	GEN7_3DPRIM_END_OFFSET,
>  	GEN7_3DPRIM_START_VERTEX,
>  	GEN7_3DPRIM_VERTEX_COUNT,
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index ea84e1e..9275d41 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -314,6 +314,8 @@
>  #define   MI_BATCH_GTT		    (2<<6) /* aliased with (1<<7) on gen4 */
>  #define MI_BATCH_BUFFER_START_GEN8	MI_INSTR(0x31, 1)
>  
> +#define MI_PREDICATE_SRC0	(0x2400)
> +#define MI_PREDICATE_SRC1	(0x2408)
>  
>  #define MI_PREDICATE_RESULT_2	(0x2214)
>  #define  LOWER_SLICE_ENABLED	(1<<0)
> -- 
> 1.9.3
> 
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