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@xxxxxxxxx>
> ---
> 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.
> +
> + 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.
>
> 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.
> + 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.
> + 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.
> + /*
> + * 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.
> + 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@xxxxxxxxxxxxxxx>
>
> 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
--
Ville Syrjälä
Intel
