Re: [PATCH v2 2/4] drm/i915/dg2: Introduce DG2_WA subplatform

[Raag Jadav <raag.jadav@intel.com>]

On Fri, Oct 11, 2024 at 01:44:01PM +0300, Jani Nikula wrote:
> On Fri, 11 Oct 2024, Raag Jadav <raag.jadav@intel.com> wrote:
> > Introduce DG2_WA subplatform for the devices that will be used in a
> > workaround and span across multiple DG2 subplatforms.
> 
> Ditto, give the subplatform a name other than "WA". Look up the specs,
> what's in common?

This WA is basically for G8 power state which reduces idle power.

I initially opted for _G8 but it didn't sit quite well with existing G10, G11 macros
which I'm guessing means something else?

Perhaps we can use _PM, but it would be a bit misleading as well, since it has nothing
to do with Linux PM.

Open to suggestions.

> > Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h          |  2 ++
> >  drivers/gpu/drm/i915/intel_device_info.c | 34 +++++++++++++++++-------
> >  drivers/gpu/drm/i915/intel_device_info.h |  5 +++-
> >  3 files changed, 31 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index 39f6614a0a99..0a68cd9379e8 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -548,6 +548,8 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
> >  	IS_SUBPLATFORM(i915, INTEL_DG2, INTEL_SUBPLATFORM_G11)
> >  #define IS_DG2_G12(i915) \
> >  	IS_SUBPLATFORM(i915, INTEL_DG2, INTEL_SUBPLATFORM_G12)
> > +#define IS_DG2_WA(i915) \
> > +	IS_SUBPLATFORM(i915, INTEL_DG2, INTEL_SUBPLATFORM_WA)
> >  #define IS_RAPTORLAKE_S(i915) \
> >  	IS_SUBPLATFORM(i915, INTEL_ALDERLAKE_S, INTEL_SUBPLATFORM_RPL)
> >  #define IS_ALDERLAKE_P_N(i915) \
> > diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
> > index 3c47c625993e..674ab2a4d75e 100644
> > --- a/drivers/gpu/drm/i915/intel_device_info.c
> > +++ b/drivers/gpu/drm/i915/intel_device_info.c
> > @@ -200,6 +200,15 @@ static const u16 subplatform_g12_ids[] = {
> >  	INTEL_DG2_G12_IDS(ID),
> >  };
> >  
> > +static const u16 subplatform_dg2_wa_ids[] = {
> > +	INTEL_DG2_WA_IDS(ID),
> > +};
> > +
> > +static const u16 subplatform_dg2_ids[] = {
> > +	INTEL_DG2_IDS(ID),
> > +	INTEL_ATS_M_IDS(ID),
> > +};
> 
> Nope, you don't need this.
> 
> > +
> >  static const u16 subplatform_arl_ids[] = {
> >  	INTEL_ARL_IDS(ID),
> >  };
> > @@ -252,15 +261,22 @@ static void intel_device_info_subplatform_init(struct drm_i915_private *i915)
> >  		if (find_devid(devid, subplatform_rplu_ids,
> >  			       ARRAY_SIZE(subplatform_rplu_ids)))
> >  			mask |= BIT(INTEL_SUBPLATFORM_RPLU);
> > -	} else if (find_devid(devid, subplatform_g10_ids,
> > -			      ARRAY_SIZE(subplatform_g10_ids))) {
> > -		mask = BIT(INTEL_SUBPLATFORM_G10);
> > -	} else if (find_devid(devid, subplatform_g11_ids,
> > -			      ARRAY_SIZE(subplatform_g11_ids))) {
> > -		mask = BIT(INTEL_SUBPLATFORM_G11);
> > -	} else if (find_devid(devid, subplatform_g12_ids,
> > -			      ARRAY_SIZE(subplatform_g12_ids))) {
> > -		mask = BIT(INTEL_SUBPLATFORM_G12);
> > +	} else if (find_devid(devid, subplatform_dg2_ids,
> > +			      ARRAY_SIZE(subplatform_dg2_ids))) {
> 
> Nope. Just hoist the below checks to higher level.

With that, won't we need to duplicate wa_ids check for each?

> > +		if (find_devid(devid, subplatform_g10_ids,
> > +			       ARRAY_SIZE(subplatform_g10_ids)))
> > +			mask = BIT(INTEL_SUBPLATFORM_G10);
> > +		else if (find_devid(devid, subplatform_g11_ids,
> > +				    ARRAY_SIZE(subplatform_g11_ids)))
> > +			mask = BIT(INTEL_SUBPLATFORM_G11);
> > +		else if (find_devid(devid, subplatform_g12_ids,
> > +				    ARRAY_SIZE(subplatform_g12_ids)))
> > +			mask = BIT(INTEL_SUBPLATFORM_G12);
> > +
> > +		/* DG2 WA ids span across multiple subplatforms */
> > +		if (find_devid(devid, subplatform_dg2_wa_ids,
> > +			       ARRAY_SIZE(subplatform_dg2_wa_ids)))
> > +			mask |= BIT(INTEL_SUBPLATFORM_WA);
> >  	} else if (find_devid(devid, subplatform_arl_ids,
> >  			      ARRAY_SIZE(subplatform_arl_ids))) {
> >  		mask = BIT(INTEL_SUBPLATFORM_ARL);
> > diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
> > index 643ff1bf74ee..c3623e859c78 100644
> > --- a/drivers/gpu/drm/i915/intel_device_info.h
> > +++ b/drivers/gpu/drm/i915/intel_device_info.h
> > @@ -95,9 +95,11 @@ enum intel_platform {
> >  /*
> >   * Subplatform bits share the same namespace per parent platform. In other words
> >   * it is fine for the same bit to be used on multiple parent platforms.
> > + * Devices can belong to multiple subplatforms if needed, so it's possible to set
> > + * multiple bits for same device.
> >   */
> >  
> > -#define INTEL_SUBPLATFORM_BITS (3)
> > +#define INTEL_SUBPLATFORM_BITS (4)
> >  #define INTEL_SUBPLATFORM_MASK (BIT(INTEL_SUBPLATFORM_BITS) - 1)
> >  
> >  /* HSW/BDW/SKL/KBL/CFL */
> > @@ -114,6 +116,7 @@ enum intel_platform {
> >  #define INTEL_SUBPLATFORM_G10	0
> >  #define INTEL_SUBPLATFORM_G11	1
> >  #define INTEL_SUBPLATFORM_G12	2
> > +#define INTEL_SUBPLATFORM_WA	3
> >  
> >  /* ADL */
> >  #define INTEL_SUBPLATFORM_RPL	0
> 
> -- 
> Jani Nikula, Intel