On Tue, Nov 13, 2018 at 05:52:16PM -0800, Manasi Navare wrote:
> DSC params like the enable, compressed bpp, slice count and
> dsc_split are added to the intel_crtc_state. These parameters
> are set based on the requested mode and available link parameters
> during the pipe configuration in atomic check phase.
> These values are then later used to populate the remaining DSC
> and RC parameters before enbaling DSC in atomic commit.
>
> v13:
> * Compute DSC bpc only when DSC is req to be enabled (Ville)
> v12:
> * Override bpp with dsc dpcd color depth (Manasi)
> v11:
> * Const crtc_state, reject DSC on DP without FEC (Ville)
> * Dont set dsc_split to false (Ville)
> v10:
> * Add a helper for dp_dsc support (Ville)
> * Set pipe_config to max bpp, link params for DSC for now (Ville)
> * Compute bpp - use dp dsc support helper (Ville)
> v9:
> * Rebase on top of drm-tip that now uses fast_narrow config
> for edp (Manasi)
> v8:
> * Check for DSC bpc not 0 (manasi)
>
> v7:
> * Fix indentation in compute_m_n (Manasi)
>
> v6 (From Gaurav):
> * Remove function call of intel_dp_compute_dsc_params() and
> invoke intel_dp_compute_dsc_params() in the patch where
> it is defined to fix compilation warning (Gaurav)
>
> v5:
> Add drm_dsc_cfg in intel_crtc_state (Manasi)
>
> v4:
> * Rebase on refactoring of intel_dp_compute_config on tip (Manasi)
> * Add a comment why we need to check PSR while enabling DSC (Gaurav)
>
> v3:
> * Check PPR > max_cdclock to use 2 VDSC instances (Ville)
>
> v2:
> * Add if-else for eDP/DP (Gaurav)
>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Anusha Srivatsa <anusha.srivatsa@xxxxxxxxx>
> Cc: Gaurav K Singh <gaurav.k.singh@xxxxxxxxx>
> Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> Reviewed-by: Anusha Srivatsa <anusha.srivatsa@xxxxxxxxx>
> Acked-by: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_display.c | 20 ++-
> drivers/gpu/drm/i915/intel_display.h | 3 +-
> drivers/gpu/drm/i915/intel_dp.c | 187 ++++++++++++++++++++++++---
> drivers/gpu/drm/i915/intel_dp_mst.c | 2 +-
> 4 files changed, 184 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 132e978227fb..390c4b3970db 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6483,7 +6483,7 @@ static int ironlake_fdi_compute_config(struct intel_crtc *intel_crtc,
>
> pipe_config->fdi_lanes = lane;
>
> - intel_link_compute_m_n(pipe_config->pipe_bpp, lane, fdi_dotclock,
> + intel_link_compute_m_n(pipe_config->pipe_bpp, 0, lane, fdi_dotclock,
> link_bw, &pipe_config->fdi_m_n, false);
>
> ret = ironlake_check_fdi_lanes(dev, intel_crtc->pipe, pipe_config);
> @@ -6723,17 +6723,25 @@ static void compute_m_n(unsigned int m, unsigned int n,
> }
>
> void
> -intel_link_compute_m_n(int bits_per_pixel, int nlanes,
> +intel_link_compute_m_n(int bits_per_pixel, uint16_t compressed_bpp,
> + int nlanes,
> int pixel_clock, int link_clock,
> struct intel_link_m_n *m_n,
> bool constant_n)
> {
> m_n->tu = 64;
>
> - compute_m_n(bits_per_pixel * pixel_clock,
> - link_clock * nlanes * 8,
> - &m_n->gmch_m, &m_n->gmch_n,
> - constant_n);
> + /* For DSC, Data M/N calculation uses compressed BPP */
> + if (compressed_bpp)
The extra parameter seems to be pointless. Just pass
compressed_bpp instead of pipe_bpp and it'll do what
you want.
> + compute_m_n(compressed_bpp * pixel_clock,
> + link_clock * nlanes * 8,
> + &m_n->gmch_m, &m_n->gmch_n,
> + constant_n);
> + else
> + compute_m_n(bits_per_pixel * pixel_clock,
> + link_clock * nlanes * 8,
> + &m_n->gmch_m, &m_n->gmch_n,
> + constant_n);
>
> compute_m_n(pixel_clock, link_clock,
> &m_n->link_m, &m_n->link_n,
> diff --git a/drivers/gpu/drm/i915/intel_display.h b/drivers/gpu/drm/i915/intel_display.h
> index 5d50decbcbb5..b0b23e1e9392 100644
> --- a/drivers/gpu/drm/i915/intel_display.h
> +++ b/drivers/gpu/drm/i915/intel_display.h
> @@ -407,7 +407,8 @@ struct intel_link_m_n {
> (__i)++) \
> for_each_if(plane)
>
> -void intel_link_compute_m_n(int bpp, int nlanes,
> +void intel_link_compute_m_n(int bpp, uint16_t compressed_bpp,
> + int nlanes,
> int pixel_clock, int link_clock,
> struct intel_link_m_n *m_n,
> bool constant_n);
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 2b090609bee2..931c3c7e55c1 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -47,6 +47,8 @@
>
> /* DP DSC small joiner has 2 FIFOs each of 640 x 6 bytes */
> #define DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER 61440
> +#define DP_DSC_MIN_SUPPORTED_BPC 8
> +#define DP_DSC_MAX_SUPPORTED_BPC 10
>
> /* DP DSC throughput values used for slice count calculations KPixels/s */
> #define DP_DSC_PEAK_PIXEL_RATE 2720000
> @@ -1708,6 +1710,29 @@ struct link_config_limits {
> int min_bpp, max_bpp;
> };
>
> +static bool intel_dp_source_supports_dsc(struct intel_dp *intel_dp,
> + const struct intel_crtc_state *pipe_config)
> +{
> + struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> +
> + /* FIXME: FEC needed for external DP until then reject DSC on DP */
> + if (!intel_dp_is_edp(intel_dp))
> + return false;
> +
> + return INTEL_GEN(dev_priv) >= 10 &&
> + pipe_config->cpu_transcoder != TRANSCODER_A;
> +}
> +
> +static bool intel_dp_supports_dsc(struct intel_dp *intel_dp,
> + const struct intel_crtc_state *pipe_config)
> +{
> + if (!intel_dp_source_supports_dsc(intel_dp, pipe_config) ||
> + !drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd))
> + return false;
Or slightly more straightforward:
return intel_dp_source_supports_dsc() &&
drm_dp_sink_supports_dsc();
I generally like to read these sort of things outloud to myself.
That usually helps pick out the least convoluted form.
> +
> + return true;
> +}
> +
> static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
> struct intel_crtc_state *pipe_config)
> {
> @@ -1842,14 +1867,118 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> return false;
> }
>
> +static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
> +{
> + int i;
> + u8 dsc_sink_color_depth_cap[8] = {0};
The variable name isn't very descriptive. Just bpc[], dsc_bpc[] etc. would
seem better. And three elements should be all we need.
> +
> + drm_dp_dsc_sink_color_depth_cap(intel_dp->dsc_dpcd,
> + dsc_sink_color_depth_cap);
The function name isn't all that descriptive either.
drm_dp_dsc_supported_input_bpcs() maybe?
> + for (i = 0; i < ARRAY_SIZE(dsc_sink_color_depth_cap); i++) {
> + if (dsc_max_bpc <= dsc_sink_color_depth_cap[i])
This test seems the wrong way around.
> + return dsc_sink_color_depth_cap[i] * 3;
> + }
> +
> + return 0;
> +}
> +
> +static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> + struct intel_crtc_state *pipe_config,
> + struct drm_connector_state *conn_state,
> + struct link_config_limits *limits)
> +{
> + struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> + struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> + struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> + u8 dsc_max_bpc;
> + u16 dsc_max_output_bpp = 0;
> + u8 dsc_dp_slice_count = 0;
> + int pipe_bpp;
> +
> + if (!intel_dp_supports_dsc(intel_dp, pipe_config))
> + return false;
> +
> + dsc_max_bpc = min_t(u8, DP_DSC_MAX_SUPPORTED_BPC,
> + conn_state->max_requested_bpc);
> +
> + if (dsc_max_bpc < DP_DSC_MIN_SUPPORTED_BPC) {
> + DRM_DEBUG_KMS("No DSC support for less than 8bpc\n");
> + return false;
> + }
We don't really need this check here. intel_dp_dsc_compute_bpp()
will return 0 if the max is below any supported value. So we can
rely on the check afterwards.
> + pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, dsc_max_bpc);
> + if (!pipe_bpp || pipe_bpp < DP_DSC_MIN_SUPPORTED_BPC * 3) {
The !pipe_bpp check is redundant.
> + DRM_DEBUG_KMS("No DSC support for less than 8bpc\n");
> + return false;
> + }
> +
> + /*
> + * For now enable DSC for max bpp, max link rate, max lane count.
> + * Optimize this later for the minimum possible link rate/lane count
> + * with DSC enabled for the requested mode.
> + */
> + pipe_config->pipe_bpp = pipe_bpp;
> + pipe_config->port_clock = intel_dp->common_rates[limits->max_clock];
> + pipe_config->lane_count = limits->max_lane_count;
> +
> + if (intel_dp_is_edp(intel_dp)) {
> + pipe_config->dsc_params.compressed_bpp =
> + min_t(u16, drm_edp_dsc_sink_output_bpp(intel_dp->dsc_dpcd) >> 4,
> + pipe_config->pipe_bpp);
> + pipe_config->dsc_params.slice_count =
> + drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
> + true);
> + } else {
> + dsc_max_output_bpp =
> + intel_dp_dsc_get_output_bpp(pipe_config->port_clock,
> + pipe_config->lane_count,
> + adjusted_mode->crtc_clock,
> + adjusted_mode->crtc_hdisplay);
> + dsc_dp_slice_count =
> + intel_dp_dsc_get_slice_count(intel_dp,
> + adjusted_mode->crtc_clock,
> + adjusted_mode->crtc_hdisplay);
> + if (!(dsc_max_output_bpp && dsc_dp_slice_count)) {
> + DRM_DEBUG_KMS("Compressed BPP/Slice Count not supported\n");
> + return false;
> + }
> + pipe_config->dsc_params.compressed_bpp = min_t(u16,
> + dsc_max_output_bpp >> 4,
> + pipe_config->pipe_bpp);
> + pipe_config->dsc_params.slice_count = dsc_dp_slice_count;
> + }
> + /*
> + * VDSC engine operates at 1 Pixel per clock, so if peak pixel rate
> + * is greater than the maximum Cdclock and if slice count is even
> + * then we need to use 2 VDSC instances.
> + */
> + if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq) {
> + if (pipe_config->dsc_params.slice_count > 1) {
> + pipe_config->dsc_params.dsc_split = true;
> + } else {
> + DRM_DEBUG_KMS("Cannot split stream to use 2 VDSC instances\n");
> + return false;
> + }
> + }
> + pipe_config->dsc_params.compression_enable = true;
> + DRM_DEBUG_KMS("DP DSC computed with Input Bpp = %d "
> + "Compressed Bpp = %d Slice Count = %d\n",
> + pipe_config->pipe_bpp,
> + pipe_config->dsc_params.compressed_bpp,
> + pipe_config->dsc_params.slice_count);
> +
> + return true;
> +}
> +
> static bool
> intel_dp_compute_link_config(struct intel_encoder *encoder,
> - struct intel_crtc_state *pipe_config)
> + struct intel_crtc_state *pipe_config,
> + struct drm_connector_state *conn_state)
> {
> struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
> struct link_config_limits limits;
> int common_len;
> + bool ret = false;
Unecessary initialization AFAICS.
>
> common_len = intel_dp_common_len_rate_limit(intel_dp,
> intel_dp->max_link_rate);
> @@ -1863,8 +1992,8 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> limits.min_lane_count = 1;
> limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
>
> - limits.min_bpp = 6 * 3;
> limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
> + limits.min_bpp = 6 * 3;
Leftovers
>
> if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> /*
> @@ -1888,7 +2017,7 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> intel_dp->common_rates[limits.max_clock],
> limits.max_bpp, adjusted_mode->crtc_clock);
>
> - if (intel_dp_is_edp(intel_dp)) {
> + if (intel_dp_is_edp(intel_dp))
> /*
> * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> * section A.1: "It is recommended that the minimum number of
> @@ -1898,26 +2027,42 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> * Note that we use the max clock and lane count for eDP 1.3 and
> * earlier, and fast vs. wide is irrelevant.
> */
> - if (!intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> - &limits))
> - return false;
> - } else {
> + ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> + &limits);
> + else
> /* Optimize for slow and wide. */
> - if (!intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> - &limits))
> + ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> + &limits);
> +
> + /* enable compression if the mode doesn't fit available BW */
> + if (!ret) {
> + if (!intel_dp_dsc_compute_config(intel_dp, pipe_config,
> + conn_state, &limits))
> return false;
> }
>
> - DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n",
> - pipe_config->lane_count, pipe_config->port_clock,
> - pipe_config->pipe_bpp);
> + if (pipe_config->dsc_params.compression_enable) {
> + DRM_DEBUG_KMS("DP lane count %d clock %d Input bpp %d Compressed bpp %d\n",
> + pipe_config->lane_count, pipe_config->port_clock,
> + pipe_config->pipe_bpp,
> + pipe_config->dsc_params.compressed_bpp);
>
> - DRM_DEBUG_KMS("DP link rate required %i available %i\n",
> - intel_dp_link_required(adjusted_mode->crtc_clock,
> - pipe_config->pipe_bpp),
> - intel_dp_max_data_rate(pipe_config->port_clock,
> - pipe_config->lane_count));
> + DRM_DEBUG_KMS("DP link rate required %i available %i\n",
> + intel_dp_link_required(adjusted_mode->crtc_clock,
> + pipe_config->dsc_params.compressed_bpp),
> + intel_dp_max_data_rate(pipe_config->port_clock,
> + pipe_config->lane_count));
> + } else {
> + DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n",
> + pipe_config->lane_count, pipe_config->port_clock,
> + pipe_config->pipe_bpp);
>
> + DRM_DEBUG_KMS("DP link rate required %i available %i\n",
> + intel_dp_link_required(adjusted_mode->crtc_clock,
> + pipe_config->pipe_bpp),
> + intel_dp_max_data_rate(pipe_config->port_clock,
> + pipe_config->lane_count));
> + }
> return true;
> }
>
> @@ -1983,7 +2128,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> if (adjusted_mode->flags & DRM_MODE_FLAG_DBLCLK)
> return false;
>
> - if (!intel_dp_compute_link_config(encoder, pipe_config))
> + if (!intel_dp_compute_link_config(encoder, pipe_config, conn_state))
> return false;
>
> if (intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_AUTO) {
> @@ -2001,7 +2146,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_LIMITED;
> }
>
> - intel_link_compute_m_n(pipe_config->pipe_bpp, pipe_config->lane_count,
> + intel_link_compute_m_n(pipe_config->pipe_bpp,
> + pipe_config->dsc_params.compressed_bpp,
> + pipe_config->lane_count,
> adjusted_mode->crtc_clock,
> pipe_config->port_clock,
> &pipe_config->dp_m_n,
> @@ -2010,7 +2157,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> if (intel_connector->panel.downclock_mode != NULL &&
> dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) {
> pipe_config->has_drrs = true;
> - intel_link_compute_m_n(pipe_config->pipe_bpp,
> + intel_link_compute_m_n(pipe_config->pipe_bpp, 0,
> pipe_config->lane_count,
> intel_connector->panel.downclock_mode->clock,
> pipe_config->port_clock,
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> index 4de247ddf05f..3f346b2e3b48 100644
> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -90,7 +90,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> }
> }
>
> - intel_link_compute_m_n(bpp, lane_count,
> + intel_link_compute_m_n(bpp, 0, lane_count,
> adjusted_mode->crtc_clock,
> pipe_config->port_clock,
> &pipe_config->dp_m_n,
> --
> 2.19.1
--
Ville Syrjälä
Intel
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