Re: [PATCH] drm/i915/gen11: Add Wa_1604278689:icl,ehl

[Matt Roper <matthew.d.roper@intel.com>]

On Mon, Aug 19, 2019 at 07:13:56PM +0300, Ville Syrjälä wrote:
> On Thu, Aug 15, 2019 at 02:58:59PM -0700, Matt Roper wrote:
> > From the bspec:
> > 
> >         "SW must always program the FBC_RT_BASE_ADDR_REGISTER_* register
> >         in Render Engine to a reserved value (0xFFFF_FFFF) such that the
> >         programmed value doesn’t match the render target surface address
> >         programmed. This would disable render engine from generating
> >         modify messages to FBC unit in display."
> 
> This looks a bit peculiar. That magic value seems to imply that the
> RT_VALID bit no longer functions as intended. I filed a spec issue to
> get some clarification on this.

Yeah, this worried me as well, although I figured their logic was that
turning on the 'valid' bit was okay as long as the address comparisons
always returned a mismatch.  However CI starts failing with this
workaround applied, and experimentation with trybot indicates that
the failures go away when I add a "& ~RT_VALID" to the RT_BASE register
value.  I'll submit an updated version that turns that bit off in a bit.


Matt

> 
> > 
> > Bspec: 11388
> > Bspec: 33451
> > Cc: José Roberto de Souza <jose.souza@intel.com>
> > Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> > ---
> >  drivers/gpu/drm/i915/gt/intel_workarounds.c | 6 ++++++
> >  drivers/gpu/drm/i915/i915_reg.h             | 1 +
> >  2 files changed, 7 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > index 704ace01e7f5..29b50e2c0627 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> > @@ -567,6 +567,12 @@ static void icl_ctx_workarounds_init(struct intel_engine_cs *engine,
> >  	/* allow headerless messages for preemptible GPGPU context */
> >  	WA_SET_BIT_MASKED(GEN10_SAMPLER_MODE,
> >  			  GEN11_SAMPLER_ENABLE_HEADLESS_MSG);
> > +
> > +	/* Wa_1604278689:icl,ehl */
> > +	wa_write_masked_or(wal, IVB_FBC_RT_BASE_UPPER,
> > +			   0, /* write-only register; skip validation */
> > +			   0xFFFFFFFF);
> > +	wa_write(wal, IVB_FBC_RT_BASE, 0xFFFFFFFF);
> >  }
> >  
> >  static void
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index def6dbdc7e2e..14af1b1dc0d3 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -3214,6 +3214,7 @@ enum i915_power_well_id {
> >  
> >  /* Framebuffer compression for Ivybridge */
> >  #define IVB_FBC_RT_BASE			_MMIO(0x7020)
> > +#define IVB_FBC_RT_BASE_UPPER		_MMIO(0x7024)
> 
> That register seems to be BDW+ actually.
> 
> >  
> >  #define IPS_CTL		_MMIO(0x43408)
> >  #define   IPS_ENABLE	(1 << 31)
> > -- 
> > 2.20.1
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795
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