Re: [RFC 4/6] drm/i915/dp: Program VSC Header and DB for Pixel Encoding/Colorimetry Format

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Op 31-01-2019 om 22:10 schreef Gwan-gyeong Mun:
> Function intel_pixel_encoding_setup_vsc handles vsc header and data block
> setup for pixel encoding / colorimetry format.
>
> Setup VSC header and data block in function intel_pixel_encoding_setup_vsc
> for pixel encoding / colorimetry format as per dp 1.4a spec,
> section 2.2.5.7.1, table 2-119: VSC SDP Header Bytes, section 2.2.5.7.5,
> table 2-120:VSC SDP Payload for DB16 through DB18.
>
> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c |  1 +
>  drivers/gpu/drm/i915/intel_dp.c  | 72 ++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h |  2 +
>  3 files changed, 75 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index ca705546a0ab..8969f03393b8 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -3400,6 +3400,7 @@ static void intel_enable_ddi_dp(struct intel_encoder *encoder,
>  
>  	intel_edp_backlight_on(crtc_state, conn_state);
>  	intel_psr_enable(intel_dp, crtc_state);
> +	intel_dp_ycbcr_420_enable(intel_dp, crtc_state);
>  	intel_edp_drrs_enable(intel_dp, crtc_state);
>  
>  	if (crtc_state->has_audio)
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index a61aff23c8b2..3a9a5a3c33a9 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4402,6 +4402,78 @@ u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
>  	return 0;
>  }
>  
> +static void
> +intel_pixel_encoding_setup_vsc(struct intel_dp *intel_dp,
> +			       const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> +	struct dp_vsc_sdp vsc_sdp;
> +
> +	if (!intel_dp->attached_connector->base.ycbcr_420_allowed)  return;
> +
Newline missing?
> +	/* Prepare VSC Header for SU as per DP 1.4a spec, Table 2-119 */
> +	memset(&vsc_sdp, 0, sizeof(vsc_sdp));
> +	vsc_sdp.sdp_header.HB0 = 0;
> +	vsc_sdp.sdp_header.HB1 = 0x7;
> +
> +	/* VSC SDP supporting 3D stereo, PSR2, and Pixel Encoding/
> +	 * Colorimetry Format indication. A DP Source device is allowed
> +	 * to indicate the pixel encoding/colorimetry format to the DP Sink
> +	 * device with VSC SDP only when the DP Sink device supports it
> +	 * (i.e., VSC_SDP_EXTENSION_FOR_COLORIMETRY_SUPPORTED bit in the register
> +	 * DPRX_FEATURE_ENUMERATION_LIST (DPCD Address 02210h, bit 3) is set to 1)
> +	 */
> +	vsc_sdp.sdp_header.HB2 = 0x5;
> +
> +	/* VSC SDP supporting 3D stereo, + PSR2, + Pixel Encoding/
> +	 * Colorimetry Format indication (HB2 = 05h).
> +	 */
> +	vsc_sdp.sdp_header.HB3 = 0x13;
> +	/* YCbCr 420 = 3h DB16[7:4] ITU-R BT.601 = 0h, ITU-R BT.709 = 1h
> +	 * DB16[3:0] DP 1.4a spec, Table 2-120
> +	 */
> +
> +	/* https://patchwork.freedesktop.org/patch/166830/ i915 implementations
> +	 * uses BT.709 color space
> +	 */
I think we should refer to commit ids instead of patchwork. :)
> +	vsc_sdp.DB16 = 0x3 << 4; /* 0x3 << 4 , YCbCr 420*/
> +	vsc_sdp.DB16 |= 0x1; /* 0x1, ITU-R BT.709 */

But speaking of patchwork, might be nice to setup a VSC for not yuv420 as well.

This could be used for https://patchwork.freedesktop.org/series/47132/

:)

> +	/* For pixel encoding formats YCbCr444, YCbCr422, YCbCr420, and Y Only,
> +	 * the following Component Bit Depth values are defined:
> +	 * 001b = 8bpc.
> +	 * 010b = 10bpc.
> +	 * 011b = 12bpc.
> +	 * 100b = 16bpc.
> +	 */
> +	vsc_sdp.DB17 = 0x1;
> +
> +	/*
> +	 * Content Type (Bits 2:0)
> +	 * 000b = Not defined.
> +	 * 001b = Graphics.
> +	 * 010b = Photo.
> +	 * 011b = Video.
> +	 * 100b = Game
> +	 * All other values are RESERVED.
> +	 * Note: See CTA-861-G for the definition and expected
> +	 * processing by a stream sink for the above contect types.
> +	 */
> +	vsc_sdp.DB18 = 0;
> +
> +	intel_dig_port->write_infoframe(&intel_dig_port->base,
> +			crtc_state, DP_SDP_VSC, &vsc_sdp, sizeof(vsc_sdp));
> +}
> +

This should probably be less hardcoded in the future, but looks ok for now.

~Maarten

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