Re: [PATCH v4 08/10] drm/i915/dsb: Enable gamma lut programming using DSB.

[Jani Nikula <jani.nikula@intel.com>]

On Fri, 30 Aug 2019, Jani Nikula <jani.nikula@intel.com> wrote:
> On Fri, 30 Aug 2019, Animesh Manna <animesh.manna@intel.com> wrote:
>> Gamma lut programming can be programmed using DSB
>> where bulk register programming can be done using indexed
>> register write which takes number of data and the mmio offset
>> to be written.
>>
>> v1: Initial version.
>> v2: Directly call dsb-api at callsites. (Jani)
>>
>> Cc: Jani Nikula <jani.nikula@intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_color.c | 64 ++++++++++++++--------
>>  drivers/gpu/drm/i915/i915_drv.h            |  2 +
>>  2 files changed, 43 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
>> index 71a0201437a9..e4090d8e4547 100644
>> --- a/drivers/gpu/drm/i915/display/intel_color.c
>> +++ b/drivers/gpu/drm/i915/display/intel_color.c
>> @@ -589,34 +589,38 @@ static void bdw_load_lut_10(struct intel_crtc *crtc,
>>  	const struct drm_color_lut *lut = blob->data;
>>  	int i, lut_size = drm_color_lut_size(blob);
>>  	enum pipe pipe = crtc->pipe;
>> +	struct intel_dsb *dsb = dev_priv->dsb;
>
> No. Don't put dsb in dev_priv. You have 12 DSB engines, 3 per pipe. You
> have intel_crtc for that.
>
> Was this not clear from my previous review?
>
> You have tons of functions here that will never have a DSB engine, it
> makes no sense to convert all of them to use the DSB.

To clarify:

All functions that could and should use the DSB, need to be converted to
use intel_dsb_write and friends. That means replacing I915_WRITE with
the relevant intel_dsb_write calls. *NOT* having if (dsb)
intel_dsb_write else I915_WRITE. As agreed a long time ago,
intel_dsb_write should handle the non-DSB cases by falling back to
regular intel_uncore_write.

My point is, if there are functions that will never be called on a
platform that has DSB, there's no point in converting them over to use
DSB. Obviously there are e.g. legacy gamma functions that also get
called on newer platforms.

Maybe I was hasty in my assesment, need to double check if all of these
paths are reachable from DSB platforms.


BR,
Jani.


>
>>  
>> -	I915_WRITE(PREC_PAL_INDEX(pipe), prec_index |
>> -		   PAL_PREC_AUTO_INCREMENT);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_INDEX(pipe),
>> +			    prec_index | PAL_PREC_AUTO_INCREMENT);
>>  
>>  	for (i = 0; i < hw_lut_size; i++) {
>>  		/* We discard half the user entries in split gamma mode */
>>  		const struct drm_color_lut *entry =
>>  			&lut[i * (lut_size - 1) / (hw_lut_size - 1)];
>>  
>> -		I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_10(entry));
>> +		intel_dsb_indexed_reg_write(dsb, PREC_PAL_DATA(pipe),
>> +					    ilk_lut_10(entry));
>>  	}
>>  
>>  	/*
>>  	 * Reset the index, otherwise it prevents the legacy palette to be
>>  	 * written properly.
>>  	 */
>> -	I915_WRITE(PREC_PAL_INDEX(pipe), 0);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_INDEX(pipe), 0);
>>  }
>>  
>>  static void ivb_load_lut_ext_max(struct intel_crtc *crtc)
>>  {
>>  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>> +	struct intel_dsb *dsb = dev_priv->dsb;
>>  	enum pipe pipe = crtc->pipe;
>>  
>>  	/* Program the max register to clamp values > 1.0. */
>> -	I915_WRITE(PREC_PAL_EXT_GC_MAX(pipe, 0), 1 << 16);
>> -	I915_WRITE(PREC_PAL_EXT_GC_MAX(pipe, 1), 1 << 16);
>> -	I915_WRITE(PREC_PAL_EXT_GC_MAX(pipe, 2), 1 << 16);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_EXT_GC_MAX(pipe, 0), 1 << 16);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_EXT_GC_MAX(pipe, 1), 1 << 16);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_EXT_GC_MAX(pipe, 2), 1 << 16);
>> +
>>  
>>  	/*
>>  	 * Program the gc max 2 register to clamp values > 1.0.
>> @@ -624,9 +628,12 @@ static void ivb_load_lut_ext_max(struct intel_crtc *crtc)
>>  	 * from 3.0 to 7.0
>>  	 */
>>  	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv)) {
>> -		I915_WRITE(PREC_PAL_EXT2_GC_MAX(pipe, 0), 1 << 16);
>> -		I915_WRITE(PREC_PAL_EXT2_GC_MAX(pipe, 1), 1 << 16);
>> -		I915_WRITE(PREC_PAL_EXT2_GC_MAX(pipe, 2), 1 << 16);
>> +		intel_dsb_reg_write(dsb, PREC_PAL_EXT2_GC_MAX(pipe, 0),
>> +				    1 << 16);
>> +		intel_dsb_reg_write(dsb, PREC_PAL_EXT2_GC_MAX(pipe, 1),
>> +				    1 << 16);
>> +		intel_dsb_reg_write(dsb, PREC_PAL_EXT2_GC_MAX(pipe, 2),
>> +				    1 << 16);
>>  	}
>>  }
>>  
>> @@ -788,12 +795,13 @@ icl_load_gcmax(const struct intel_crtc_state *crtc_state,
>>  {
>>  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
>>  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>> +	struct intel_dsb *dsb = dev_priv->dsb;
>>  	enum pipe pipe = crtc->pipe;
>>  
>>  	/* Fixme: LUT entries are 16 bit only, so we can prog 0xFFFF max */
>> -	I915_WRITE(PREC_PAL_GC_MAX(pipe, 0), color->red);
>> -	I915_WRITE(PREC_PAL_GC_MAX(pipe, 1), color->green);
>> -	I915_WRITE(PREC_PAL_GC_MAX(pipe, 2), color->blue);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_GC_MAX(pipe, 0), color->red);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_GC_MAX(pipe, 1), color->green);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_GC_MAX(pipe, 2), color->blue);
>>  }
>>  
>>  static void
>> @@ -803,6 +811,7 @@ icl_program_gamma_superfine_segment(const struct intel_crtc_state *crtc_state)
>>  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>>  	const struct drm_property_blob *blob = crtc_state->base.gamma_lut;
>>  	const struct drm_color_lut *lut = blob->data;
>> +	struct intel_dsb *dsb = dev_priv->dsb;
>>  	enum pipe pipe = crtc->pipe;
>>  	u32 i;
>>  
>> @@ -813,15 +822,16 @@ icl_program_gamma_superfine_segment(const struct intel_crtc_state *crtc_state)
>>  	 * Superfine segment has 9 entries, corresponding to values
>>  	 * 0, 1/(8 * 128 * 256), 2/(8 * 128 * 256) .... 8/(8 * 128 * 256).
>>  	 */
>> -	I915_WRITE(PREC_PAL_MULTI_SEG_INDEX(pipe), PAL_PREC_AUTO_INCREMENT);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_MULTI_SEG_INDEX(pipe),
>> +			    PAL_PREC_AUTO_INCREMENT);
>>  
>>  	for (i = 0; i < 9; i++) {
>>  		const struct drm_color_lut *entry = &lut[i];
>>  
>> -		I915_WRITE(PREC_PAL_MULTI_SEG_DATA(pipe),
>> -			   ilk_lut_12p4_ldw(entry));
>> -		I915_WRITE(PREC_PAL_MULTI_SEG_DATA(pipe),
>> -			   ilk_lut_12p4_udw(entry));
>> +		intel_dsb_indexed_reg_write(dsb, PREC_PAL_MULTI_SEG_DATA(pipe),
>> +					    ilk_lut_12p4_ldw(entry));
>> +		intel_dsb_indexed_reg_write(dsb, PREC_PAL_MULTI_SEG_DATA(pipe),
>> +					    ilk_lut_12p4_udw(entry));
>>  	}
>>  }
>>  
>> @@ -833,6 +843,7 @@ icl_program_gamma_multi_segment(const struct intel_crtc_state *crtc_state)
>>  	const struct drm_property_blob *blob = crtc_state->base.gamma_lut;
>>  	const struct drm_color_lut *lut = blob->data;
>>  	const struct drm_color_lut *entry;
>> +	struct intel_dsb *dsb = dev_priv->dsb;
>>  	enum pipe pipe = crtc->pipe;
>>  	u32 i;
>>  
>> @@ -847,11 +858,13 @@ icl_program_gamma_multi_segment(const struct intel_crtc_state *crtc_state)
>>  	 * PAL_PREC_INDEX[0] and PAL_PREC_INDEX[1] map to seg2[1],
>>  	 * with seg2[0] being unused by the hardware.
>>  	 */
>> -	I915_WRITE(PREC_PAL_INDEX(pipe), PAL_PREC_AUTO_INCREMENT);
>> +	intel_dsb_reg_write(dsb, PREC_PAL_INDEX(pipe), PAL_PREC_AUTO_INCREMENT);
>>  	for (i = 1; i < 257; i++) {
>>  		entry = &lut[i * 8];
>> -		I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_ldw(entry));
>> -		I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_udw(entry));
>> +		intel_dsb_indexed_reg_write(dsb, PREC_PAL_DATA(pipe),
>> +					    ilk_lut_12p4_ldw(entry));
>> +		intel_dsb_indexed_reg_write(dsb, PREC_PAL_DATA(pipe),
>> +					    ilk_lut_12p4_udw(entry));
>>  	}
>>  
>>  	/*
>> @@ -868,8 +881,10 @@ icl_program_gamma_multi_segment(const struct intel_crtc_state *crtc_state)
>>  	 */
>>  	for (i = 0; i < 256; i++) {
>>  		entry = &lut[i * 8 * 128];
>> -		I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_ldw(entry));
>> -		I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_udw(entry));
>> +		intel_dsb_indexed_reg_write(dsb, PREC_PAL_DATA(pipe),
>> +					    ilk_lut_12p4_ldw(entry));
>> +		intel_dsb_indexed_reg_write(dsb, PREC_PAL_DATA(pipe),
>> +					    ilk_lut_12p4_udw(entry));
>>  	}
>>  
>>  	/* The last entry in the LUT is to be programmed in GCMAX */
>> @@ -980,7 +995,10 @@ void intel_color_load_luts(const struct intel_crtc_state *crtc_state)
>>  {
>>  	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
>>  
>> +	dev_priv->dsb = intel_dsb_get(to_intel_crtc(crtc_state->base.crtc));
>
> No, don't do this. Don't store crtc specific info in a device global
> structure.
>
>>  	dev_priv->display.load_luts(crtc_state);
>> +	intel_dsb_commit(dev_priv->dsb);
>> +	intel_dsb_put(dev_priv->dsb);
>
> Please localize the use of DSB where needed. Move the gets and puts
> within the relevant platform specific ->load_luts hooks.
>
>>  }
>>  
>>  void intel_color_commit(const struct intel_crtc_state *crtc_state)
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index 7aa11e3dd413..98f546c4ad49 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -1760,6 +1760,8 @@ struct drm_i915_private {
>>  	/* Mutex to protect the above hdcp component related values. */
>>  	struct mutex hdcp_comp_mutex;
>>  
>> +	struct intel_dsb *dsb;
>> +
>>  	/*
>>  	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
>>  	 * will be rejected. Instead look for a better place.

-- 
Jani Nikula, Intel Open Source Graphics Center
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