On Thu, Nov 03, 2022 at 03:23:00PM +0200, Stanislav Lisovskiy wrote:
> Fix intel_dp_dsc_compute_config, previously timeslots parameter
> was used in fact not as a timeslots, but more like a ratio
> timeslots/64, which of course didn't have any effect for SST DSC,
> but causes now issues for MST DSC.
> Secondly we need to calculate pipe_bpp using intel_dp_dsc_compute_bpp
> only for SST DSC case, while for MST case it has been calculated
> earlier already with intel_dp_dsc_mst_compute_link_config.
> Third we also were wrongly determining sink min bpp/max bpp, those
> limites should be intersected with our limits to find common
> acceptable bpp's, plus on top of that we should align those with
> VESA bpps and only then calculate required timeslots amount.
> Some MST hubs started to work only after third change was made.
>
> v2: Make kernel test robot happy(claimed there was unitialzed use,
> while there is none)
>
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovs...@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 69 ++++++++++++++-------
> drivers/gpu/drm/i915/display/intel_dp.h | 3 +-
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 69 +++++++++++++++++----
> 3 files changed, 106 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 8288a30dbd51..82752b696498 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -716,9 +716,14 @@ u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private
> *i915,
> * for SST -> TimeSlotsPerMTP is 1,
> * for MST -> TimeSlotsPerMTP has to be calculated
> */
> - bits_per_pixel = (link_clock * lane_count * 8) * timeslots /
> - intel_dp_mode_to_fec_clock(mode_clock);
> - drm_dbg_kms(&i915->drm, "Max link bpp: %u\n", bits_per_pixel);
> + bits_per_pixel = DIV_ROUND_UP((link_clock * lane_count) * timeslots,
> + intel_dp_mode_to_fec_clock(mode_clock) *
> 8);
Why did we remove the *8 in the numerator for the total bandwidth
link_clock * lane_count * 8 ?
Other than this clarification, all changes look good
Manasi
> +
> + drm_dbg_kms(&i915->drm, "Max link bpp is %u for %u timeslots "
> + "total bw %u pixel clock %u\n",
> + bits_per_pixel, timeslots,
> + (link_clock * lane_count * 8),
> + intel_dp_mode_to_fec_clock(mode_clock));
>
> /* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
> max_bpp_small_joiner_ram = small_joiner_ram_size_bits(i915) /
> @@ -1047,7 +1052,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
> target_clock,
> mode->hdisplay,
> bigjoiner,
> - pipe_bpp, 1) >> 4;
> + pipe_bpp, 64) >> 4;
> dsc_slice_count =
> intel_dp_dsc_get_slice_count(intel_dp,
> target_clock,
> @@ -1481,7 +1486,8 @@ int 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,
> - int timeslots)
> + int timeslots,
> + bool compute_pipe_bpp)
> {
> 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);
> @@ -1496,7 +1502,10 @@ int intel_dp_dsc_compute_config(struct intel_dp
> *intel_dp,
> if (!intel_dp_supports_dsc(intel_dp, pipe_config))
> return -EINVAL;
>
> - pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp,
> conn_state->max_requested_bpc);
> + if (compute_pipe_bpp)
> + pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp,
> conn_state->max_requested_bpc);
> + else
> + pipe_bpp = pipe_config->pipe_bpp;
>
> if (intel_dp->force_dsc_bpc) {
> pipe_bpp = intel_dp->force_dsc_bpc * 3;
> @@ -1527,31 +1536,47 @@ int intel_dp_dsc_compute_config(struct intel_dp
> *intel_dp,
> drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
> true);
> } else {
> - u16 dsc_max_output_bpp;
> + u16 dsc_max_output_bpp = 0;
> u8 dsc_dp_slice_count;
>
> - dsc_max_output_bpp =
> - intel_dp_dsc_get_output_bpp(dev_priv,
> - pipe_config->port_clock,
> - pipe_config->lane_count,
> - adjusted_mode->crtc_clock,
> -
> adjusted_mode->crtc_hdisplay,
> -
> pipe_config->bigjoiner_pipes,
> - pipe_bpp,
> - timeslots);
> + if (compute_pipe_bpp) {
> + dsc_max_output_bpp =
> + intel_dp_dsc_get_output_bpp(dev_priv,
> +
> pipe_config->port_clock,
> +
> pipe_config->lane_count,
> +
> adjusted_mode->crtc_clock,
> +
> adjusted_mode->crtc_hdisplay,
> +
> pipe_config->bigjoiner_pipes,
> + pipe_bpp,
> + timeslots);
> + if (!dsc_max_output_bpp) {
> + drm_dbg_kms(&dev_priv->drm,
> + "Compressed BPP not supported\n");
> + return -EINVAL;
> + }
> + }
> dsc_dp_slice_count =
> intel_dp_dsc_get_slice_count(intel_dp,
> adjusted_mode->crtc_clock,
>
> adjusted_mode->crtc_hdisplay,
>
> pipe_config->bigjoiner_pipes);
> - if (!dsc_max_output_bpp || !dsc_dp_slice_count) {
> + if (!dsc_dp_slice_count) {
> drm_dbg_kms(&dev_priv->drm,
> - "Compressed BPP/Slice Count not
> supported\n");
> + "Compressed Slice Count not supported\n");
> return -EINVAL;
> }
> - pipe_config->dsc.compressed_bpp = min_t(u16,
> - dsc_max_output_bpp >> 4,
> - pipe_config->pipe_bpp);
> +
> + /*
> + * compute pipe bpp is set to false for DP MST DSC case
> + * and compressed_bpp is calculated same time once
> + * vpci timeslots are allocated, because overall bpp
> + * calculation procedure is bit different for MST case.
> + */
> + if (compute_pipe_bpp) {
> + pipe_config->dsc.compressed_bpp = min_t(u16,
> +
> dsc_max_output_bpp >> 4,
> +
> pipe_config->pipe_bpp);
> + }
> pipe_config->dsc.slice_count = dsc_dp_slice_count;
> drm_dbg_kms(&dev_priv->drm, "DSC: compressed bpp %d slice count
> %d\n",
> pipe_config->dsc.compressed_bpp,
> @@ -1659,7 +1684,7 @@ intel_dp_compute_link_config(struct intel_encoder
> *encoder,
> str_yes_no(ret), str_yes_no(joiner_needs_dsc),
> str_yes_no(intel_dp->force_dsc_en));
> ret = intel_dp_dsc_compute_config(intel_dp, pipe_config,
> - conn_state, &limits, 1);
> + conn_state, &limits, 1, true);
> if (ret < 0)
> return ret;
> }
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h
> b/drivers/gpu/drm/i915/display/intel_dp.h
> index 0fe10d93b75c..75098001685a 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -60,7 +60,8 @@ int 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,
> - int timeslots);
> + int timeslots,
> + bool recompute_pipe_bpp);
> bool intel_dp_is_edp(struct intel_dp *intel_dp);
> bool intel_dp_is_uhbr(const struct intel_crtc_state *crtc_state);
> bool intel_dp_is_port_edp(struct drm_i915_private *dev_priv, enum port port);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 8442eea27a57..69e383decb39 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -80,12 +80,12 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct
> intel_encoder *encoder,
> }
>
> for (bpp = max_bpp; bpp >= min_bpp; bpp -= step) {
> - crtc_state->pipe_bpp = bpp;
> -
> crtc_state->pbn =
> drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
> - dsc ? bpp << 4 :
> crtc_state->pipe_bpp,
> + dsc ? bpp << 4 : bpp,
> dsc);
>
> + drm_dbg_kms(&i915->drm, "Trying bpp %d\n", bpp);
> +
> slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
> connector->port,
> crtc_state->pbn);
> @@ -107,9 +107,16 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct
> intel_encoder *encoder,
> if (ret && slots >= 0)
> slots = ret;
>
> - if (slots < 0)
> + if (slots < 0) {
> drm_dbg_kms(&i915->drm, "failed finding vcpi slots:%d\n",
> slots);
> + } else {
> + if (!dsc)
> + crtc_state->pipe_bpp = bpp;
> + else
> + crtc_state->dsc.compressed_bpp = bpp;
> + drm_dbg_kms(&i915->drm, "Got %d slots for pipe bpp %d dsc
> %d\n", slots, bpp, dsc);
> + }
>
> return slots;
> }
> @@ -156,8 +163,10 @@ static int intel_dp_dsc_mst_compute_link_config(struct
> intel_encoder *encoder,
> int slots = -EINVAL;
> int i, num_bpc;
> u8 dsc_bpc[3] = {0};
> - int min_bpp, max_bpp;
> + int min_bpp, max_bpp, sink_min_bpp, sink_max_bpp;
> u8 dsc_max_bpc;
> + bool need_timeslot_recalc = false;
> + u32 last_compressed_bpp;
>
> /* Max DSC Input BPC for ICL is 10 and for TGL+ is 12 */
> if (DISPLAY_VER(i915) >= 12)
> @@ -170,14 +179,28 @@ static int intel_dp_dsc_mst_compute_link_config(struct
> intel_encoder *encoder,
>
> num_bpc = drm_dp_dsc_sink_supported_input_bpcs(intel_dp->dsc_dpcd,
> dsc_bpc);
> - for (i = 0; i < num_bpc; i++) {
> - if (max_bpp >= dsc_bpc[i] * 3)
> - if (min_bpp > dsc_bpc[i] * 3)
> - min_bpp = dsc_bpc[i] * 3;
> +
> + drm_dbg_kms(&i915->drm, "DSC Source supported min bpp %d max bpp %d\n",
> + min_bpp, max_bpp);
> +
> + sink_max_bpp = dsc_bpc[0] * 3;
> + sink_min_bpp = sink_max_bpp;
> +
> + for (i = 1; i < num_bpc; i++) {
> + if (sink_min_bpp > dsc_bpc[i] * 3)
> + sink_min_bpp = dsc_bpc[i] * 3;
> + if (sink_max_bpp < dsc_bpc[i] * 3)
> + sink_max_bpp = dsc_bpc[i] * 3;
> }
>
> drm_dbg_kms(&i915->drm, "DSC Sink supported min bpp %d max bpp %d\n",
> - min_bpp, max_bpp);
> + sink_min_bpp, sink_max_bpp);
> +
> + if (min_bpp < sink_min_bpp)
> + min_bpp = sink_min_bpp;
> +
> + if (max_bpp > sink_max_bpp)
> + max_bpp = sink_max_bpp;
>
> slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state,
> max_bpp,
> min_bpp, limits,
> @@ -186,6 +209,28 @@ static int intel_dp_dsc_mst_compute_link_config(struct
> intel_encoder *encoder,
> if (slots < 0)
> return slots;
>
> + last_compressed_bpp = crtc_state->dsc.compressed_bpp;
> +
> + crtc_state->dsc.compressed_bpp = intel_dp_dsc_nearest_vesa_bpp(i915,
> +
> last_compressed_bpp,
> +
> crtc_state->pipe_bpp);
> +
> + if (crtc_state->dsc.compressed_bpp != last_compressed_bpp)
> + need_timeslot_recalc = true;
> +
> + /*
> + * Apparently some MST hubs dislike if vcpi slots are not matching
> precisely
> + * the actual compressed bpp we use.
> + */
> + if (need_timeslot_recalc) {
> + slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder,
> crtc_state,
> +
> crtc_state->dsc.compressed_bpp,
> +
> crtc_state->dsc.compressed_bpp,
> + limits,
> conn_state, 2 * 3, true);
> + if (slots < 0)
> + return slots;
> + }
> +
> intel_link_compute_m_n(crtc_state->pipe_bpp,
> crtc_state->lane_count,
> adjusted_mode->crtc_clock,
> @@ -292,7 +337,7 @@ static int intel_dp_mst_compute_config(struct
> intel_encoder *encoder,
>
> ret = intel_dp_dsc_compute_config(intel_dp, pipe_config,
> conn_state, &limits,
> - pipe_config->dp_m_n.tu);
> + pipe_config->dp_m_n.tu,
> false);
> }
>
> if (ret)
> @@ -867,7 +912,7 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector
> *connector,
> target_clock,
> mode->hdisplay,
> bigjoiner,
> - pipe_bpp, 1) >> 4;
> + pipe_bpp, 64) >> 4;
> dsc_slice_count =
> intel_dp_dsc_get_slice_count(intel_dp,
> target_clock,
> --
> 2.37.3
>
