Re: [PATCH v4 15/16] drm/i915: Let PCON convert from RGB to YUV if it can

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 12/13/2020 12:53 PM, Shankar, Uma wrote:
>
>> -----Original Message-----
>> From: Nautiyal, Ankit K <ankit.k.nautiyal@intel.com>
>> Sent: Tuesday, December 8, 2020 1:22 PM
>> To: intel-gfx@lists.freedesktop.org
>> Cc: dri-devel@lists.freedesktop.org; Shankar, Uma <uma.shankar@intel.com>;
>> airlied@linux.ie; jani.nikula@linux.intel.com; ville.syrjala@linux.intel.com;
>> Kulkarni, Vandita <vandita.kulkarni@intel.com>; Sharma, Swati2
>> <swati2.sharma@intel.com>
>> Subject: [PATCH v4 15/16] drm/i915: Let PCON convert from RGB to YUV if it can
> Make it drm/i915/display:
Noted. Will change in next version of the patch
>
>> If PCON has capability to convert RGB->YUV colorspace and also to 444->420
>> downsampling then for any YUV420 only mode, we can let the PCON do all the
>> conversion.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>> ---
>>   .../drm/i915/display/intel_display_types.h    |  1 +
>>   drivers/gpu/drm/i915/display/intel_dp.c       | 37 +++++++++++++------
>>   2 files changed, 26 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
>> b/drivers/gpu/drm/i915/display/intel_display_types.h
>> index b41de41759a0..4150108bdc6d 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>> @@ -1460,6 +1460,7 @@ struct intel_dp {
>>   		int pcon_max_frl_bw, sink_max_frl_bw;
>>   		u8 max_bpc;
>>   		bool ycbcr_444_to_420;
>> +		bool rgb_to_ycbcr;
>>   	} dfp;
>>
>>   	/* Display stream compression testing */ diff --git
>> a/drivers/gpu/drm/i915/display/intel_dp.c
>> b/drivers/gpu/drm/i915/display/intel_dp.c
>> index 30c76ba63232..b3f1190d8150 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -651,6 +651,10 @@ intel_dp_output_format(struct drm_connector
>> *connector,
>>   	    !drm_mode_is_420_only(info, mode))
>>   		return INTEL_OUTPUT_FORMAT_RGB;
>>
>> +	if (intel_dp->dfp.rgb_to_ycbcr &&
>> +	    intel_dp->dfp.ycbcr_444_to_420)
>> +		return INTEL_OUTPUT_FORMAT_RGB;
>> +
>>   	if (intel_dp->dfp.ycbcr_444_to_420)
>>   		return INTEL_OUTPUT_FORMAT_YCBCR444;
>>   	else
>> @@ -4365,13 +4369,12 @@ void intel_dp_configure_protocol_converter(struct
>> intel_dp *intel_dp)
>>   			    "Failed to set protocol converter YCbCr 4:2:0
>> conversion mode to %s\n",
>>   			    enableddisabled(intel_dp->dfp.ycbcr_444_to_420));
>>
>> -	tmp = 0;
>> -
>> -	if (drm_dp_dpcd_writeb(&intel_dp->aux,
>> -			       DP_PROTOCOL_CONVERTER_CONTROL_2, tmp) <= 0)
>> +	tmp = intel_dp->dfp.rgb_to_ycbcr ?
>> +		DP_CONVERSION_BT601_RGB_YCBCR_ENABLE : 0;
> There are other combinations also possible like BT709 and BT2020. Handle those as well here.
> If no colorspace data is provided we can make BT601 as default, but if user chooses a colorspace
> and pcon supports it, then we should go for that option. We can get that info from connector
> colorspace properties.

Agreed. I will take into account color space in version of the patch.

For DP we set vsc.colorspace in pipe_config from connector colorspace, 
so I can use that information to take a call if its rec 709 or BT2020.

As suggested will use BT601 as default.

Thanks & Regards,

Ankit

>
>> +	if (drm_dp_pcon_convert_rgb_to_ycbcr(&intel_dp->aux, tmp) <= 0)
>>   		drm_dbg_kms(&i915->drm,
>> -			    "Failed to set protocol converter YCbCr 4:2:2
>> conversion mode to %s\n",
>> -			    enableddisabled(false));
>> +			    "Failed to set protocol converter RGB->YCbCr
>> conversion mode to %s\n",
>> +			    enableddisabled(intel_dp->dfp.rgb_to_ycbcr));
>>   }
>>
>>   static void intel_enable_dp(struct intel_atomic_state *state, @@ -6897,7
>> +6900,7 @@ intel_dp_update_420(struct intel_dp *intel_dp)  {
>>   	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>>   	struct intel_connector *connector = intel_dp->attached_connector;
>> -	bool is_branch, ycbcr_420_passthrough, ycbcr_444_to_420;
>> +	bool is_branch, ycbcr_420_passthrough, ycbcr_444_to_420, rgb_to_ycbcr;
>>
>>   	/* No YCbCr output support on gmch platforms */
>>   	if (HAS_GMCH(i915))
>> @@ -6919,14 +6922,23 @@ intel_dp_update_420(struct intel_dp *intel_dp)
>>   		dp_to_dig_port(intel_dp)->lspcon.active ||
>>   		drm_dp_downstream_444_to_420_conversion(intel_dp->dpcd,
>>   							intel_dp-
>>> downstream_ports);
>> +	rgb_to_ycbcr = drm_dp_downstream_rgb_to_ycbcr_conversion(intel_dp-
>>> dpcd,
>> +							intel_dp-
>>> downstream_ports);
>>   	if (INTEL_GEN(i915) >= 11) {
>> +		/* Let PCON convert from RGB->YCbCr if possible */
>> +		if (is_branch && rgb_to_ycbcr && ycbcr_444_to_420) {
>> +			intel_dp->dfp.rgb_to_ycbcr = true;
>> +			intel_dp->dfp.ycbcr_444_to_420 = true;
>> +			connector->base.ycbcr_420_allowed = true;
>> +		} else {
>>   		/* Prefer 4:2:0 passthrough over 4:4:4->4:2:0 conversion */
>> -		intel_dp->dfp.ycbcr_444_to_420 =
>> -			ycbcr_444_to_420 && !ycbcr_420_passthrough;
>> +			intel_dp->dfp.ycbcr_444_to_420 =
>> +				ycbcr_444_to_420 && !ycbcr_420_passthrough;
>>
>> -		connector->base.ycbcr_420_allowed =
>> -			!is_branch || ycbcr_444_to_420 ||
>> ycbcr_420_passthrough;
>> +			connector->base.ycbcr_420_allowed =
>> +				!is_branch || ycbcr_444_to_420 ||
>> ycbcr_420_passthrough;
>> +		}
>>   	} else {
>>   		/* 4:4:4->4:2:0 conversion is the only way */
>>   		intel_dp->dfp.ycbcr_444_to_420 = ycbcr_444_to_420; @@ -
>> 6935,8 +6947,9 @@ intel_dp_update_420(struct intel_dp *intel_dp)
>>   	}
>>
>>   	drm_dbg_kms(&i915->drm,
>> -		    "[CONNECTOR:%d:%s] YCbCr 4:2:0 allowed? %s, YCbCr 4:4:4-
>>> 4:2:0 conversion? %s\n",
>> +		    "[CONNECTOR:%d:%s] RGB->YcbCr conversion? %s, YCbCr 4:2:0
>> +allowed? %s, YCbCr 4:4:4->4:2:0 conversion? %s\n",
>>   		    connector->base.base.id, connector->base.name,
>> +		    yesno(intel_dp->dfp.rgb_to_ycbcr),
>>   		    yesno(connector->base.ycbcr_420_allowed),
>>   		    yesno(intel_dp->dfp.ycbcr_444_to_420));
>>   }
>> --
>> 2.17.1
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