Re: [Intel-gfx] [PATCH] drm/i915: disable sampler indirect state in bindless heap

["Kalvala, Haridhar" <haridhar.kalvala@intel.com>]

On 3/9/2023 8:56 PM, Lionel Landwerlin wrote:
> By default the indirect state sampler data (border colors) are stored
> in the same heap as the SAMPLER_STATE structure. For userspace drivers
> that can be 2 different heaps (dynamic state heap & bindless sampler
> state heap). This means that border colors have to copied in 2
> different places so that the same SAMPLER_STATE structure find the
> right data.
>
> This change is forcing the indirect state sampler data to only be in
> the dynamic state pool (more convinient for userspace drivers, they
> only have to have one copy of the border colors). This is reproducing
> the behavior of the Windows drivers.
>
> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
> Cc: stable@vger.kernel.org
> ---
>   drivers/gpu/drm/i915/gt/intel_gt_regs.h     |  1 +
>   drivers/gpu/drm/i915/gt/intel_workarounds.c | 17 +++++++++++++++++
>   2 files changed, 18 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> index 08d76aa06974c..1aaa471d08c56 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> @@ -1141,6 +1141,7 @@
>   #define   ENABLE_SMALLPL			REG_BIT(15)
>   #define   SC_DISABLE_POWER_OPTIMIZATION_EBB	REG_BIT(9)
>   #define   GEN11_SAMPLER_ENABLE_HEADLESS_MSG	REG_BIT(5)
> +#define   GEN11_INDIRECT_STATE_BASE_ADDR_OVERRIDE	REG_BIT(0)
>   
>   #define GEN9_HALF_SLICE_CHICKEN7		MCR_REG(0xe194)
>   #define   DG2_DISABLE_ROUND_ENABLE_ALLOW_FOR_SSLA	REG_BIT(15)
> diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> index 32aa1647721ae..734b64e714647 100644
> --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> @@ -2542,6 +2542,23 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
>   				 ENABLE_SMALLPL);
>   	}
>   
> +	if (GRAPHICS_VER(i915) >= 11) {

Hi Lionel,

Not sure should this implementation be part of "rcs_engine_wa_init" or 
"general_render_compute_wa_init".

> +		/* This is not a Wa (although referred to as
> +		 * WaSetInidrectStateOverride in places), this allows
> +		 * applications that reference sampler states through
> +		 * the BindlessSamplerStateBaseAddress to have their
> +		 * border color relative to DynamicStateBaseAddress
> +		 * rather than BindlessSamplerStateBaseAddress.
> +		 *
> +		 * Otherwise SAMPLER_STATE border colors have to be
> +		 * copied in multiple heaps (DynamicStateBaseAddress &
> +		 * BindlessSamplerStateBaseAddress)
> +		 */
> +		wa_mcr_masked_en(wal,
> +				 GEN10_SAMPLER_MODE,

  since we checking the condition for GEN11 or above, can this register 
be defined as GEN11_SAMPLER_MODE

> +				 GEN11_INDIRECT_STATE_BASE_ADDR_OVERRIDE);
> +	}
> +
>   	if (GRAPHICS_VER(i915) == 11) {
>   		/* This is not an Wa. Enable for better image quality */
>   		wa_masked_en(wal,

-- 
Regards,
Haridhar Kalvala