[Intel-gfx] [PATCH v11 03/11] drm/i915/dp: Replace intel_dp.dfp members with the new crtc_state sink_format

Nautiyal, Ankit K ankit.k.nautiyal at intel.com
Fri Mar 17 10:48:23 UTC 2023


Hi Ville,

Thanks for the reviews and comments.

I agree to the suggested changes and will address them in next version 
of the patch.

Please find my responses inline.

On 3/17/2023 5:16 AM, Ville Syrjälä wrote:
> On Tue, Mar 14, 2023 at 04:34:07PM +0530, Ankit Nautiyal wrote:
>> The decision to use DFP output format conversion capabilities should be
>> during compute_config phase.
>>
>> This patch uses the members of intel_dp->dfp to only store the
>> format conversion capabilities of the DP device and uses the crtc_state
>> sink_format member, to program the protocol-converter for
>> colorspace/format conversion.
>>
>> v2: Use sink_format to determine the color conversion config for the
>> pcon (Ville).
>>
>> v3: Fix typo: missing 'break' in switch case (lkp kernel test robot).
>>
>> v4: Add helper to check if DP supports YCBCR420.
>>
>> v5: Simplify logic for computing output_format, based on the given
>> sink_format. (Ville).
>> Added scaler constraint for YCbCr420 output.
>>
>> v6: Split the patch for Scaler constraint for Ycbcr420.
>>
>> v7: Simplify the policy for selecting output_format:
>> Always try for RGB first, followed by YCBCR444, and finally by YCBCR420.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_dp.c | 182 +++++++++++++++++-------
>>   1 file changed, 129 insertions(+), 53 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>> index e52e2ffc355c..c31ec9c91c64 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -817,24 +817,82 @@ u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
>>   	return 0;
>>   }
>>   
>> +static bool source_can_output(struct intel_dp *intel_dp,
>> +			      enum intel_output_format format)
>> +{
>> +	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>> +	bool is_branch = drm_dp_is_branch(intel_dp->dpcd);
>> +
>> +	if (format == INTEL_OUTPUT_FORMAT_RGB)
>> +		return true;
>> +
>> +	/*
>> +	 * No YCbCr output support on gmch platforms.
>> +	 * Also, ILK doesn't seem capable of DP YCbCr output.
>> +	 * The displayed image is severly corrupted. SNB+ is fine.
>> +	 */
>> +	if (HAS_GMCH(i915) || IS_IRONLAKE(i915))
>> +		return false;
>> +
>> +	if (format == INTEL_OUTPUT_FORMAT_YCBCR444)
>> +		return true;
>> +
>> +	/* Platform < Gen 11 cannot output YCbCr420 format */
>> +	if (DISPLAY_VER(i915) < 11)
>> +		return false;
>> +
>> +	/* If branch device then PCONs should support YCbCr420 Passthrough */
>> +	if (format == INTEL_OUTPUT_FORMAT_YCBCR420)
>> +		return !is_branch || intel_dp->dfp.ycbcr420_passthrough;
> This part isn't really about the source capabilities.
> I think it would be more appropriate to do these checks
> in the caller.

Agreed, will move these in caller.


>> +
>> +	return false;
>> +}
>> +
>> +static bool
>> +dfp_can_convert_from_rgb(struct intel_dp *intel_dp,
>> +			 enum intel_output_format sink_format)
>> +{
>> +	if (!drm_dp_is_branch(intel_dp->dpcd))
>> +		return false;
>> +
>> +	if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444)
>> +		return intel_dp->dfp.rgb_to_ycbcr;
>> +
>> +	if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
>> +		return intel_dp->dfp.rgb_to_ycbcr &&
>> +			intel_dp->dfp.ycbcr_444_to_420;
>> +
>> +	return false;
>> +}
>> +
>> +static bool
>> +dfp_can_convert_from_ycbcr444(struct intel_dp *intel_dp,
>> +			      enum intel_output_format sink_format)
>> +{
>> +	if (!drm_dp_is_branch(intel_dp->dpcd))
>> +		return false;
>> +
>> +	if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
>> +		return intel_dp->dfp.ycbcr_444_to_420;
>> +
>> +	return false;
>> +}
>> +
>>   static enum intel_output_format
>>   intel_dp_output_format(struct intel_connector *connector,
>>   		       enum intel_output_format sink_format)
>>   {
>>   	struct intel_dp *intel_dp = intel_attached_dp(connector);
>>   
>> -	if (!connector->base.ycbcr_420_allowed ||
>> -	    sink_format != INTEL_OUTPUT_FORMAT_YCBCR420)
>> -		return INTEL_OUTPUT_FORMAT_RGB;
>> -
>> -	if (intel_dp->dfp.rgb_to_ycbcr &&
>> -	    intel_dp->dfp.ycbcr_444_to_420)
>> +	if (sink_format == INTEL_OUTPUT_FORMAT_RGB ||
>> +	    dfp_can_convert_from_rgb(intel_dp, sink_format))
>>   		return INTEL_OUTPUT_FORMAT_RGB;
>>   
>> -	if (intel_dp->dfp.ycbcr_444_to_420)
>> +	if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444 ||
>> +	    dfp_can_convert_from_ycbcr444(intel_dp, sink_format))
>>   		return INTEL_OUTPUT_FORMAT_YCBCR444;
>> -	else
>> -		return INTEL_OUTPUT_FORMAT_YCBCR420;
>> +
>> +	return INTEL_OUTPUT_FORMAT_YCBCR420;
>>   }
> I'm thinking the caller of intel_dp_output_format() might want
> to do a drm_WARN_ON(!source_can_output(output_format))
> just to make sure we didn't screw things up too badly.
>
> Or maybe we want to have that assert in intel_dp_output_format()
> itself in case there are many callers.

I think we can keep in intel_dp_output_format().

I had a check in earlier version I think, missed to add this in this 
version, but was defaulting to RGB without warn_on.

Will add a warn_on in the function as suggested.

>>   
>>   int intel_dp_min_bpp(enum intel_output_format output_format)
>> @@ -2751,6 +2809,8 @@ void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
>>   					   const struct intel_crtc_state *crtc_state)
>>   {
>>   	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>> +	bool ycbcr444_to_420 = false;
>> +	bool rgb_to_ycbcr = false;
>>   	u8 tmp;
>>   
>>   	if (intel_dp->dpcd[DP_DPCD_REV] < 0x13)
>> @@ -2767,8 +2827,35 @@ void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
>>   		drm_dbg_kms(&i915->drm, "Failed to %s protocol converter HDMI mode\n",
>>   			    str_enable_disable(intel_dp->has_hdmi_sink));
>>   
>> -	tmp = crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR444 &&
>> -		intel_dp->dfp.ycbcr_444_to_420 ? DP_CONVERSION_TO_YCBCR420_ENABLE : 0;
>> +	if (crtc_state->sink_format == INTEL_OUTPUT_FORMAT_YCBCR420) {
> I was wondering where YCBCR444 went here, but then I
> remembered that we don't have uapi for it.
>
> But even so, we could consider making this code already
> handle it. Would make it that much easier to test
> YCbCr 4:4:4 output. Should just take a one line hack
> to intel_dp_sink_format() at that point. Could be
> a followup patch though.

Makes sense, will add if (crtc_state->sink_format == 
INTEL_OUTPUT_FORMAT_YCBCR444) block.

Will try to test : going with YCbCr444 first instead on RGB, while 
selecting sink_format.

Let me add this in a follow up patch.
>
>> +		switch (crtc_state->output_format) {
>> +		case INTEL_OUTPUT_FORMAT_YCBCR420:
>> +			/*
>> +			 * sink_format is YCbCr420, output_format is also YCbCr420:
>> +			 * Passthrough.
>> +			 */
> These comments seem a bit redundant.

Alright, will remove the comments.


>
>> +			break;
>> +		case INTEL_OUTPUT_FORMAT_YCBCR444:
>> +			/*
>> +			 * sink_format is YCbCr420, output_format is YCbCr444:
>> +			 * Downsample.
>> +			 */
>> +			ycbcr444_to_420 = true;
>> +			break;
>> +		case INTEL_OUTPUT_FORMAT_RGB:
>> +			/*
>> +			 * sink_format is YCbCr420, output_format is RGB:
>> +			 * Convert to YCbCr444 and Downsample.
>> +			 */
>> +			rgb_to_ycbcr = true;
>> +			ycbcr444_to_420 = true;
>> +			break;
>> +		default:
>> +			break;
>> +		}
>> +	}
>> +
>> +	tmp = ycbcr444_to_420 ? DP_CONVERSION_TO_YCBCR420_ENABLE : 0;
>>   
>>   	if (drm_dp_dpcd_writeb(&intel_dp->aux,
>>   			       DP_PROTOCOL_CONVERTER_CONTROL_1, tmp) != 1)
>> @@ -2776,13 +2863,12 @@ void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
>>   			    "Failed to %s protocol converter YCbCr 4:2:0 conversion mode\n",
>>   			    str_enable_disable(intel_dp->dfp.ycbcr_444_to_420));
>>   
>> -	tmp = intel_dp->dfp.rgb_to_ycbcr ?
>> -		DP_CONVERSION_BT709_RGB_YCBCR_ENABLE : 0;
>> +	tmp = rgb_to_ycbcr ? DP_CONVERSION_BT709_RGB_YCBCR_ENABLE : 0;
>>   
>>   	if (drm_dp_pcon_convert_rgb_to_ycbcr(&intel_dp->aux, tmp) < 0)
>>   		drm_dbg_kms(&i915->drm,
>> -			   "Failed to %s protocol converter RGB->YCbCr conversion mode\n",
>> -			   str_enable_disable(tmp));
>> +			    "Failed to %s protocol converter RGB->YCbCr conversion mode\n",
>> +			    str_enable_disable(tmp));
>>   }
>>   
>>   bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp)
>> @@ -4572,57 +4658,47 @@ intel_dp_update_dfp(struct intel_dp *intel_dp,
>>   	intel_dp_get_pcon_dsc_cap(intel_dp);
>>   }
>>   
>> +static bool
>> +intel_dp_can_ycbcr420(struct intel_dp *intel_dp)
>> +{
>> +	if (source_can_output(intel_dp, INTEL_OUTPUT_FORMAT_YCBCR420))
>> +		return true;
> Should have an empty line here.


Noted. will add the line, in next version.

>
>> +	/*
>> +	 * If source cannot support YCbCr420, and PCON has color conv. support:
>> +	 * Source sends YCbCr444, PCON converts YCbCr444->420 Or
>> +	 * Source sends RGB444, PCON converts RGB->YCbCr444 + YCbCr444->YCbCr420)
>> +	 */
> I think the code already explains that pretty well. Comment seems
> a bit redundant.

Alright, will remove comments from here.


>> +	if (source_can_output(intel_dp, INTEL_OUTPUT_FORMAT_RGB) &&
>> +	    dfp_can_convert_from_rgb(intel_dp, INTEL_OUTPUT_FORMAT_YCBCR420))
>> +		return true;
>> +
>> +	if (source_can_output(intel_dp, INTEL_OUTPUT_FORMAT_YCBCR444) &&
>> +	    dfp_can_convert_from_ycbcr444(intel_dp, INTEL_OUTPUT_FORMAT_YCBCR420))
>> +		return INTEL_OUTPUT_FORMAT_YCBCR444;
>> +
>> +	return false;
>> +}
>> +
>>   static void
>>   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, rgb_to_ycbcr;
>> -
>> -	/* No YCbCr output support on gmch platforms */
>> -	if (HAS_GMCH(i915))
>> -		return;
>>   
>> -	/*
>> -	 * ILK doesn't seem capable of DP YCbCr output. The
>> -	 * displayed image is severly corrupted. SNB+ is fine.
>> -	 */
>> -	if (IS_IRONLAKE(i915))
>> -		return;
>> -
>> -	is_branch = drm_dp_is_branch(intel_dp->dpcd);
>> -	ycbcr_420_passthrough =
>> +	intel_dp->dfp.ycbcr420_passthrough =
>>   		drm_dp_downstream_420_passthrough(intel_dp->dpcd,
>>   						  intel_dp->downstream_ports);
>>   	/* on-board LSPCON always assumed to support 4:4:4->4:2:0 conversion */
>> -	ycbcr_444_to_420 =
>> +	intel_dp->dfp.ycbcr_444_to_420 =
>>   		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,
>> -								 DP_DS_HDMI_BT709_RGB_YCBCR_CONV);
>> -
>> -	if (DISPLAY_VER(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.rgb_to_ycbcr =
>> +		drm_dp_downstream_rgb_to_ycbcr_conversion(intel_dp->dpcd,
>> +							  intel_dp->downstream_ports,
>> +							  DP_DS_HDMI_BT709_RGB_YCBCR_CONV);
>>   
>> -			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;
>> -
>> -		connector->base.ycbcr_420_allowed = ycbcr_444_to_420;
>> -	}
>> +	connector->base.ycbcr_420_allowed = intel_dp_can_ycbcr420(intel_dp);
> Looks good. With the minor issues sorted this is
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Thanks again Ville for the suggestions and review.

Regards,

Ankit

>>   
>>   	drm_dbg_kms(&i915->drm,
>>   		    "[CONNECTOR:%d:%s] RGB->YcbCr conversion? %s, YCbCr 4:2:0 allowed? %s, YCbCr 4:4:4->4:2:0 conversion? %s\n",
>> -- 
>> 2.25.1


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