Re: [Intel-gfx] [v2] drm/i915: disable sampler indirect state in bindless heap

[Matt Atwood <matthew.s.atwood@intel.com>]

On Thu, Mar 30, 2023 at 12:27:33PM -0700, Matt Atwood wrote:
> On Thu, Mar 30, 2023 at 08:47:40PM +0300, 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
> 			       convenient 
> > only have to have one copy of the border colors). This is reproducing
> > the behavior of the Windows drivers.
> > 
> > BSpec: 46052
> > 
> Assuming still good CI results..
> Reviewed-by: Matt Atwood <matthew.s.atwood@intel.com>
My mistake version 3 required. comments inline.
> > 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 | 19 +++++++++++++++++++
> >  2 files changed, 20 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> > index 4aecb5a7b6318..f298dc461a72f 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> > @@ -1144,6 +1144,7 @@
> >  #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 e7ee24bcad893..0ce1c8c23c631 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > @@ -2535,6 +2535,25 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
> >  				 ENABLE_SMALLPL);
> >  	}
> >  
This workaround belongs in general render workarounds not rcs, as per
the address space in i915_regs.h 0x2xxx.

#define RENDER_RING_BASE        0x02000


> > +	if (GRAPHICS_VER(i915) >= 11) {
> > +		/* 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)
> > +		 *
> > +		 * BSpec: 46052
> > +		 */
> > +		wa_mcr_masked_en(wal,
> > +				 GEN10_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,
> > -- 
> > 2.34.1
> > 
MattA