[Intel-gfx] [PATCH 2/2] drm/i915: Add DSC support to MST path

Lisovskiy, Stanislav stanislav.lisovskiy at intel.com
Fri Aug 26 06:41:31 UTC 2022


On Thu, Aug 25, 2022 at 07:04:33PM +0300, Govindapillai, Vinod wrote:
> On Thu, 2022-08-25 at 18:17 +0300, Lisovskiy, Stanislav wrote:
> > On Thu, Aug 25, 2022 at 05:58:19PM +0300, Govindapillai, Vinod wrote:
> > > Hi Stan,
> > > 
> > > Some comments inline..
> > > 
> > > On Mon, 2022-08-22 at 12:40 +0300, Stanislav Lisovskiy wrote:
> > > > Whenever we are not able to get enough timeslots
> > > > for required PBN, let's try to allocate those
> > > > using DSC, just same way as we do for SST.
> > > > 
> > > > v2: Removed intel_dp_mst_dsc_compute_config and refactored
> > > >     intel_dp_dsc_compute_config to support timeslots as a
> > > >     parameter(Ville Syrjälä)
> > > > 
> > > > v3: - Rebased
> > > >     - Added a debug to see that we at least try reserving
> > > >       VCPI slots using DSC, because currently its not visible
> > > >       from the logs, thus making debugging more tricky.
> > > >     - Moved timeslots to numerator, where it should be.
> > > > 
> > > > v4: - Call drm_dp_mst_atomic_check already during link
> > > >       config computation, because we need to know already
> > > >       by this moment if uncompressed amount of VCPI slots
> > > >       needed can fit, otherwise we need to use DSC.
> > > >       (thanks to Vinod Govindapillai for pointing this out)
> > > > 
> > > > v5: - Put pipe_config->bigjoiner_pipes back to original
> > > >       condition in intel_dp_dsc_compute_config
> > > >       (don't remember when I lost it)
> > > > 
> > > > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/display/intel_dp.c     |  73 ++++-----
> > > >  drivers/gpu/drm/i915/display/intel_dp.h     |  17 +++
> > > >  drivers/gpu/drm/i915/display/intel_dp_mst.c | 157 ++++++++++++++++++++
> > > >  3 files changed, 205 insertions(+), 42 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > index 32292c0be2bd..519b436fc530 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > @@ -116,7 +116,6 @@ bool intel_dp_is_edp(struct intel_dp *intel_dp)
> > > >  }
> > > >  
> > > >  static void intel_dp_unset_edid(struct intel_dp *intel_dp);
> > > > -static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc);
> > > >  
> > > >  /* Is link rate UHBR and thus 128b/132b? */
> > > >  bool intel_dp_is_uhbr(const struct intel_crtc_state *crtc_state)
> > > > @@ -687,11 +686,12 @@ small_joiner_ram_size_bits(struct drm_i915_private *i915)
> > > >                 return 6144 * 8;
> > > >  }
> > > >  
> > > > -static u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private *i915,
> > > > -                                      u32 link_clock, u32 lane_count,
> > > > -                                      u32 mode_clock, u32 mode_hdisplay,
> > > > -                                      bool bigjoiner,
> > > > -                                      u32 pipe_bpp)
> > > > +u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private *i915,
> > > > +                               u32 link_clock, u32 lane_count,
> > > > +                               u32 mode_clock, u32 mode_hdisplay,
> > > > +                               bool bigjoiner,
> > > > +                               u32 pipe_bpp,
> > > > +                               u32 timeslots)
> > > >  {
> > > >         u32 bits_per_pixel, max_bpp_small_joiner_ram;
> > > >         int i;
> > > > @@ -702,8 +702,9 @@ static 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) /
> > > > +       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);
> > > >  
> > > >         /* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
> > > >         max_bpp_small_joiner_ram = small_joiner_ram_size_bits(i915) /
> > > > @@ -752,9 +753,9 @@ static u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private *i915,
> > > >         return bits_per_pixel << 4;
> > > >  }
> > > >  
> > > > -static u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
> > > > -                                      int mode_clock, int mode_hdisplay,
> > > > -                                      bool bigjoiner)
> > > > +u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
> > > > +                               int mode_clock, int mode_hdisplay,
> > > > +                               bool bigjoiner)
> > > >  {
> > > >         struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > >         u8 min_slice_count, i;
> > > > @@ -961,8 +962,8 @@ intel_dp_mode_valid_downstream(struct intel_connector *connector,
> > > >         return MODE_OK;
> > > >  }
> > > >  
> > > > -static bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
> > > > -                                   int hdisplay, int clock)
> > > > +bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
> > > > +                            int hdisplay, int clock)
> > > >  {
> > > >         struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > >  
> > > > @@ -1049,7 +1050,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
> > > >                                                             target_clock,
> > > >                                                             mode->hdisplay,
> > > >                                                             bigjoiner,
> > > > -                                                           pipe_bpp) >> 4;
> > > > +                                                           pipe_bpp, 1) >> 4;
> > > >                         dsc_slice_count =
> > > >                                 intel_dp_dsc_get_slice_count(intel_dp,
> > > >                                                              target_clock,
> > > > @@ -1354,7 +1355,7 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> > > >         return -EINVAL;
> > > >  }
> > > >  
> > > > -static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 max_req_bpc)
> > > > +int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 max_req_bpc)
> > > >  {
> > > >         struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > >         int i, num_bpc;
> > > > @@ -1444,10 +1445,11 @@ static int intel_dp_dsc_compute_params(struct intel_encoder *encoder,
> > > >         return drm_dsc_compute_rc_parameters(vdsc_cfg);
> > > >  }
> > > >  
> > > > -static 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 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)
> > > >  {
> > > >         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);
> > > > @@ -1498,7 +1500,8 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> > > >                                                     adjusted_mode->crtc_clock,
> > > >                                                     adjusted_mode->crtc_hdisplay,
> > > >                                                     pipe_config->bigjoiner_pipes,
> > > > -                                                   pipe_bpp);
> > > > +                                                   pipe_bpp,
> > > > +                                                   timeslots);
> > > >                 dsc_dp_slice_count =
> > > >                         intel_dp_dsc_get_slice_count(intel_dp,
> > > >                                                      adjusted_mode->crtc_clock,
> > > > @@ -1510,27 +1513,13 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> > > >                         return -EINVAL;
> > > >                 }
> > > >                 pipe_config->dsc.compressed_bpp = min_t(u16,
> > > > -                                                              dsc_max_output_bpp >> 4,
> > > > -                                                              pipe_config->pipe_bpp);
> > > > +                                                       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,
> > > > +                           pipe_config->dsc.slice_count);
> > > >         }
> > > > -
> > > > -       /* As of today we support DSC for only RGB */
> > > > -       if (intel_dp->force_dsc_bpp) {
> > > > -               if (intel_dp->force_dsc_bpp >= 8 &&
> > > > -                   intel_dp->force_dsc_bpp < pipe_bpp) {
> > > > -                       drm_dbg_kms(&dev_priv->drm,
> > > > -                                   "DSC BPP forced to %d",
> > > > -                                   intel_dp->force_dsc_bpp);
> > > > -                       pipe_config->dsc.compressed_bpp =
> > > > -                                               intel_dp->force_dsc_bpp;
> > > > -               } else {
> > > > -                       drm_dbg_kms(&dev_priv->drm,
> > > > -                                   "Invalid DSC BPP %d",
> > > > -                                   intel_dp->force_dsc_bpp);
> > > > -               }
> > > > -       }
> > > > -
> > > >         /*
> > > >          * 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
> > > > @@ -1538,13 +1527,13 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> > > >          */
> > > >         if (adjusted_mode->crtc_clock > dev_priv->max_cdclk_freq ||
> > > >             pipe_config->bigjoiner_pipes) {
> > > > -               if (pipe_config->dsc.slice_count < 2) {
> > > > +               if (pipe_config->dsc.slice_count > 1) {
> > > > +                       pipe_config->dsc.dsc_split = true;
> > > > +               } else {
> > > >                         drm_dbg_kms(&dev_priv->drm,
> > > >                                     "Cannot split stream to use 2 VDSC instances\n");
> > > >                         return -EINVAL;
> > > >                 }
> > > > -
> > > > -               pipe_config->dsc.dsc_split = true;
> > > >         }
> > > >  
> > > >         ret = intel_dp_dsc_compute_params(&dig_port->base, pipe_config);
> > > > @@ -1633,7 +1622,7 @@ 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);
> > > > +                                                 conn_state, &limits, 1);
> > > >                 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 a54902c713a3..c6539a6915e9 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_dp.h
> > > > +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> > > > @@ -56,6 +56,11 @@ void intel_dp_encoder_flush_work(struct drm_encoder *encoder);
> > > >  int intel_dp_compute_config(struct intel_encoder *encoder,
> > > >                             struct intel_crtc_state *pipe_config,
> > > >                             struct drm_connector_state *conn_state);
> > > > +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);
> > > >  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);
> > > > @@ -96,6 +101,18 @@ void intel_read_dp_sdp(struct intel_encoder *encoder,
> > > >                        struct intel_crtc_state *crtc_state,
> > > >                        unsigned int type);
> > > >  bool intel_digital_port_connected(struct intel_encoder *encoder);
> > > > +int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc);
> > > > +u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private *i915,
> > > > +                               u32 link_clock, u32 lane_count,
> > > > +                               u32 mode_clock, u32 mode_hdisplay,
> > > > +                               bool bigjoiner,
> > > > +                               u32 pipe_bpp,
> > > > +                               u32 timeslots);
> > > > +u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
> > > > +                               int mode_clock, int mode_hdisplay,
> > > > +                               bool bigjoiner);
> > > > +bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
> > > > +                            int hdisplay, int clock);
> > > >  
> > > >  static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
> > > >  {
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > > > b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > > > index 14d2a64193b2..b4d68c324e68 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > > > @@ -99,6 +99,84 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
> > > >         return 0;
> > > >  }
> > > >  
> > > > +static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
> > > > +                                               struct intel_crtc_state *crtc_state,
> > > > +                                               struct drm_connector_state *conn_state,
> > > > +                                               struct link_config_limits *limits)
> > > > +{
> > > > +       struct drm_atomic_state *state = crtc_state->uapi.state;
> > > > +       struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> > > > +       struct intel_dp *intel_dp = &intel_mst->primary->dp;
> > > > +       struct intel_connector *connector =
> > > > +               to_intel_connector(conn_state->connector);
> > > > +       struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > > > +       const struct drm_display_mode *adjusted_mode =
> > > > +               &crtc_state->hw.adjusted_mode;
> > > > +       bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
> > > > +                                          DP_DPCD_QUIRK_CONSTANT_N);
> > > > +       int bpp, slots = -EINVAL;
> > > > +       int i, num_bpc;
> > > > +       u8 dsc_bpc[3] = {0};
> > > > +       int min_bpp, max_bpp;
> > > > +       u8 dsc_max_bpc;
> > > > +
> > > > +       crtc_state->lane_count = limits->max_lane_count;
> > > > +       crtc_state->port_clock = limits->max_rate;
> > > > +
> > > > +       /* Max DSC Input BPC for ICL is 10 and for TGL+ is 12 */
> > > > +       if (DISPLAY_VER(i915) >= 12)
> > > > +               dsc_max_bpc = min_t(u8, 12, conn_state->max_requested_bpc);
> > > > +       else
> > > > +               dsc_max_bpc = min_t(u8, 10, conn_state->max_requested_bpc);
> > > > +
> > > > +       max_bpp = min_t(u8, dsc_max_bpc * 3, limits->max_bpp);
> > > > +       min_bpp = limits->min_bpp;
> > > > +
> > > > +       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 Sink supported min bpp %d max bpp %d\n",
> > > > +                   min_bpp, max_bpp);
> > > > +
> > > > +       for (bpp = max_bpp; bpp >= min_bpp; bpp -= 2 * 3) {
> > > > +               crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
> > > > +                                                      bpp << 4,
> > > > +                                                      true);
> > > > +
> > > > +               slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr,
> > > > +                                                     connector->port,
> > > > +                                                     crtc_state->pbn, 0);
> > > > +
> > > > +               drm_dbg_kms(&i915->drm, "Trying bpp %d got %d pbn %d slots\n",
> > > > +                           bpp, crtc_state->pbn, slots);
> > > > +
> > > > +               if (slots == -EDEADLK)
> > > > +                       return slots;
> > > > +               if (slots >= 0)
> > > > +                       break;
> > > Based on our understanding that drm_dp_atomic_find_vcpi_slots" doesn't check any limits, we
> > > cannot
> > > use that as a basis for "slots" decision, isnt it? Don't you need to use the same 
> > > drm_dp_mst_atomic_check() here as well? 
> > > 
> > > Or move the drm_dp_mst_atomic_check() to the intel_dp_mst_compute_link_config()?
> > 
> > That would be double check because we do call that check later in intel_atomic_check
> > anyway. I had to add it here, just to decide if we use DSC or not. However if here we
> > chose DSC and drm_dp_atomic_find_vcpi_slots returns amount of VCPI slots that can't be 
> > fit - drm_dp_mst_atomic_check which is called later in intel_atomic_check will take care
> > of that. Just like it would take care if DSC was not supported and we ran out of BW/MST slots..
> > 
> > Stan
> 
> Okay. I got that part. if you are keeping the logic like that, then there is no need to do loop over
> max_bpp to min_bpp here. Because bpp = max_bpp will never fail, the DSC will be always attempted
> with the max_bpp. And as you mentioned eventually intel_atomic_check() will catch if it is too big.
> 
> But if the intention is to find the right "bpp" which might still fit to the link, we should iterate
> over the bpp-s like you have here. But in that case the decision has to be based on one more
> "drm_dp_mst_atomic_check()"

Oh, you are right - that new finding means not only that, but also that intel_dp_mst_compute_link_config,
which I took as a template doesn't work either - because of same reason drm_dp_atomic_find_vcpi_slots 
just doesn't care if we don't have enough slots.. :(

We are also loosing opportunity to use smaller bpps here, which could allows us to fit actually, even without
DSC.. That needs to be fixed. Probably will add one patch which fixes intel_dp_mst_compute_link_config first,
then we add intel_dp_dsc_mst_compute_link_config, which works same way but with DSC. 
May be I could also extract this loop to avoid code duplication.

Stan

> 
> 
> BR
> Vinod
> > 
> > > 
> > > > +       }
> > > > +
> > > > +       if (slots < 0) {
> > > > +               drm_dbg_kms(&i915->drm, "failed finding vcpi slots:%d\n",
> > > > +                           slots);
> > > > +               return slots;
> > > > +       }
> > > > +
> > > > +       intel_link_compute_m_n(crtc_state->pipe_bpp,
> > > > +                              crtc_state->lane_count,
> > > > +                              adjusted_mode->crtc_clock,
> > > > +                              crtc_state->port_clock,
> > > > +                              &crtc_state->dp_m_n,
> > > > +                              constant_n, crtc_state->fec_enable);
> > > > +       crtc_state->dp_m_n.tu = slots;
> > > > +
> > > > +       return 0;
> > > > +}
> > > >  static int intel_dp_mst_update_slots(struct intel_encoder *encoder,
> > > >                                      struct intel_crtc_state *crtc_state,
> > > >                                      struct drm_connector_state *conn_state)
> > > > @@ -127,6 +205,7 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> > > >                                        struct drm_connector_state *conn_state)
> > > >  {
> > > >         struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > > > +       struct drm_atomic_state *state = pipe_config->uapi.state;
> > > >         struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> > > >         struct intel_dp *intel_dp = &intel_mst->primary->dp;
> > > >         struct intel_connector *connector =
> > > > @@ -175,6 +254,38 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> > > >  
> > > >         ret = intel_dp_mst_compute_link_config(encoder, pipe_config,
> > > >                                                conn_state, &limits);
> > > > +
> > > > +       if (ret == -EDEADLK)
> > > > +               return ret;
> > > > +
> > > > +       /*
> > > > +        * We need to check if VCPI slots allocated can actually fit already
> > > > +        * here, to decide whether we use DSC or not.
> > > > +        * If either intel_dp_mst_compute_link_config or that one fails,
> > > > +        * then we try DSC as last resort.
> > > > +        */
> > > > +       if (!ret)
> > > > +               ret = drm_dp_mst_atomic_check(state);
> > > > +
> > > > +       /* enable compression if the mode doesn't fit available BW */
> > > > +       drm_dbg_kms(&dev_priv->drm, "Force DSC en = %d\n", intel_dp->force_dsc_en);
> > > > +       if (ret || intel_dp->force_dsc_en) {
> > > > +               /*
> > > > +                * Try to get at least some timeslots and then see, if
> > > > +                * we can fit there with DSC.
> > > > +                */
> > > > +               drm_dbg_kms(&dev_priv->drm, "Trying to find VCPI slots in DSC mode\n");
> > > > +
> > > > +               ret = intel_dp_dsc_mst_compute_link_config(encoder, pipe_config,
> > > > +                                                          conn_state, &limits);
> > > > +               if (ret < 0)
> > > > +                       return ret;
> > > > +
> > > > +               ret = intel_dp_dsc_compute_config(intel_dp, pipe_config,
> > > > +                                                 conn_state, &limits,
> > > > +                                                 pipe_config->dp_m_n.tu);
> > > > +       }
> > > > +
> > > >         if (ret)
> > > >                 return ret;
> > > >  
> > > > @@ -713,6 +824,10 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
> > > >         int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
> > > >         int max_rate, mode_rate, max_lanes, max_link_clock;
> > > >         int ret;
> > > > +       bool dsc = false, bigjoiner = false;
> > > > +       u16 dsc_max_output_bpp = 0;
> > > > +       u8 dsc_slice_count = 0;
> > > > +       int target_clock = mode->clock;
> > > >  
> > > >         if (drm_connector_is_unregistered(connector)) {
> > > >                 *status = MODE_ERROR;
> > > > @@ -750,6 +865,48 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
> > > >                 return 0;
> > > >         }
> > > >  
> > > > +       if (intel_dp_need_bigjoiner(intel_dp, mode->hdisplay, target_clock)) {
> > > > +               bigjoiner = true;
> > > > +               max_dotclk *= 2;
> > > > +       }
> > > > +
> > > > +       if (DISPLAY_VER(dev_priv) >= 10 &&
> > > > +           drm_dp_sink_supports_dsc(intel_dp->dsc_dpcd)) {
> > > > +               /*
> > > > +                * TBD pass the connector BPC,
> > > > +                * for now U8_MAX so that max BPC on that platform would be picked
> > > > +                */
> > > > +               int pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, U8_MAX);
> > > > +
> > > > +               if (drm_dp_sink_supports_fec(intel_dp->fec_capable)) {
> > > > +                       dsc_max_output_bpp =
> > > > +                               intel_dp_dsc_get_output_bpp(dev_priv,
> > > > +                                                           max_link_clock,
> > > > +                                                           max_lanes,
> > > > +                                                           target_clock,
> > > > +                                                           mode->hdisplay,
> > > > +                                                           bigjoiner,
> > > > +                                                           pipe_bpp, 1) >> 4;
> > > > +                       dsc_slice_count =
> > > > +                               intel_dp_dsc_get_slice_count(intel_dp,
> > > > +                                                            target_clock,
> > > > +                                                            mode->hdisplay,
> > > > +                                                            bigjoiner);
> > > > +               }
> > > > +
> > > > +               dsc = dsc_max_output_bpp && dsc_slice_count;
> > > > +       }
> > > > +
> > > > +       /*
> > > > +        * Big joiner configuration needs DSC for TGL which is not true for
> > > > +        * XE_LPD where uncompressed joiner is supported.
> > > > +        */
> > > > +       if (DISPLAY_VER(dev_priv) < 13 && bigjoiner && !dsc)
> > > > +               return MODE_CLOCK_HIGH;
> > > > +
> > > > +       if (mode_rate > max_rate && !dsc)
> > > > +               return MODE_CLOCK_HIGH;
> > > > +
> > > >         *status = intel_mode_valid_max_plane_size(dev_priv, mode, false);
> > > >         return 0;
> > > >  }
> > > 
> 


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