On Wed, 29 Nov 2023 at 22:31, Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx> wrote: > > A DCE (Display Compression Engine) contains two DSC hard slice encoders. > Each DCE start with even DSC encoder index followed by an odd DSC encoder > index. Each encoder can work independently. But Only two DSC encoders from > same DCE can be paired to work together to support merge mode. In addition, > the DSC with even index have to mapping to even pingpong index and DSC with > odd index have to mapping to odd pingpong index at its data path. This patch > improve DSC allocation mechanism with consideration of above factors. Is this applicable to old DSC 1.1 encoders? > > Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx> > --- > drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 94 +++++++++++++++++++++++++++++----- > 1 file changed, 82 insertions(+), 12 deletions(-) > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c > index f9215643..427d70d 100644 > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c > @@ -466,24 +466,94 @@ static int _dpu_rm_reserve_dsc(struct dpu_rm *rm, > struct drm_encoder *enc, > const struct msm_display_topology *top) > { > - int num_dsc = top->num_dsc; > - int i; > + int num_dsc = 0; > + int i, pp_idx; > + bool pair = false; > + int dsc_idx[DSC_MAX - DSC_0]; > + uint32_t pp_to_enc_id[PINGPONG_MAX - PINGPONG_0]; > + int pp_max = PINGPONG_MAX - PINGPONG_0; > + > + if (!top->num_dsc || !top->num_intf) > + return 0; > + > + /* > + * Truth: > + * 1) every layer mixer only connects to one pingpong > + * 2) no pingpong split -- two layer mixers shared one pingpong > + * 3) each DSC engine contains two dsc encoders > + * -- index(0,1), index (2,3),... etc > + * 4) dsc pair can only happens with same DSC engine except 4 dsc > + * merge mode application (8k) which need two DSC engines > + * 5) odd pingpong connect to odd dsc > + * 6) even pingpong connect even dsc > + */ > + > + /* num_dsc should be either 1, 2 or 4 */ > + if (top->num_dsc > top->num_intf) /* merge mode */ > + pair = true; > + > + /* fill working copy with pingpong list */ > + memcpy(pp_to_enc_id, global_state->pingpong_to_enc_id, sizeof(pp_to_enc_id)); > + > + for (i = 0; i < ARRAY_SIZE(rm->dsc_blks); i++) { && num_dsc < top->num_dsc > + if (!rm->dsc_blks[i]) /* end of dsc list */ > + break; I'd say, it's `continue' instead, let's just skip the index. > > - /* check if DSC required are allocated or not */ > - for (i = 0; i < num_dsc; i++) { > - if (!rm->dsc_blks[i]) { > - DPU_ERROR("DSC %d does not exist\n", i); > - return -EIO; > + if (global_state->dsc_to_enc_id[i]) { /* used */ > + /* consective dsc index to be paired */ > + if (pair && num_dsc) { /* already start pairing, re start */ > + num_dsc = 0; > + /* fill working copy with pingpong list */ > + memcpy(pp_to_enc_id, global_state->pingpong_to_enc_id, > + sizeof(pp_to_enc_id)); > + } > + continue; > } > > - if (global_state->dsc_to_enc_id[i]) { > - DPU_ERROR("DSC %d is already allocated\n", i); > - return -EIO; > + /* odd index can not become start of pairing */ > + if (pair && (i & 0x01) && !num_dsc) > + continue; After looking at all conditions, can we have two different helpers? One which allocates a single DSC and another one which allocates a pair. For the pair you can skip odd indices at all and just check if DSC_i and DSC_i+1 are free. > + > + /* > + * find the pingpong index which had been reserved > + * previously at layer mixer allocation > + */ > + for (pp_idx = 0; pp_idx < pp_max; pp_idx++) { > + if (pp_to_enc_id[pp_idx] == enc->base.id) > + break; > } > + > + /* > + * dsc even index must map to pingpong even index > + * dsc odd index must map to pingpong odd index > + */ > + if ((i & 0x01) != (pp_idx & 0x01)) > + continue; > + > + /* > + * delete pp_idx so that it can not be found at next search > + * in the case of pairing > + */ > + pp_to_enc_id[pp_idx] = NULL; > + > + dsc_idx[num_dsc++] = i; > + if (num_dsc >= top->num_dsc) > + break; > } > > - for (i = 0; i < num_dsc; i++) > - global_state->dsc_to_enc_id[i] = enc->base.id; > + if (num_dsc < top->num_dsc) { > + DPU_ERROR("DSC allocation failed num_dsc=%d required=%d\n", > + num_dsc, top->num_dsc ); > + return -ENAVAIL; > + } > + > + /* reserve dsc */ > + for (i = 0; i < top->num_dsc; i++) { > + int j; > + > + j = dsc_idx[i]; > + global_state->dsc_to_enc_id[j] = enc->base.id; > + } > > return 0; > } > -- > 2.7.4 > -- With best wishes Dmitry