Re: [PATCH 06/12] drm/msm/dpu: make changes to dpu_encoder to support virtual encoder

On 2022-02-04 13:17:19, Abhinav Kumar wrote:

Make changes to dpu_encoder to support virtual encoder needed to support writeback for dpu.

Signed-off-by: Abhinav Kumar quic_abhinavk@quicinc.com

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 57 +++++++++++++++++++++-------- 1 file changed, 42 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c index e977c05..947069b 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c @@ -974,6 +974,7 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc, struct dpu_hw_blk *hw_ctl[MAX_CHANNELS_PER_ENC]; struct dpu_hw_blk *hw_lm[MAX_CHANNELS_PER_ENC]; struct dpu_hw_blk *hw_dspp[MAX_CHANNELS_PER_ENC] = { NULL };

• enum dpu_hw_blk_type blk_type; int num_lm, num_ctl, num_pp; int i, j;

@@ -1061,20 +1062,36 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc, phys->hw_pp = dpu_enc->hw_pp[i]; phys->hw_ctl = to_dpu_hw_ctl(hw_ctl[i]);

• if (phys->intf_mode == INTF_MODE_WB_LINE)
  

• 	blk_type = DPU_HW_BLK_WB;
  

• else
  

• 	blk_type = DPU_HW_BLK_INTF;
  

• num_blk = dpu_rm_get_assigned_resources(&dpu_kms->rm,

• 	global_state, drm_enc->base.id, DPU_HW_BLK_INTF,
  

• 	global_state, drm_enc->base.id, blk_type,
  hw_blk, ARRAY_SIZE(hw_blk));
  

• for (j = 0; j < num_blk; j++) {
  

• 	struct dpu_hw_intf *hw_intf;
  
  

• 	hw_intf = to_dpu_hw_intf(hw_blk[i]);
  

• 	if (hw_intf->idx == phys->intf_idx)
  

• 		phys->hw_intf = hw_intf;
  

• if (blk_type == DPU_HW_BLK_WB) {
  

• 	for (j = 0; j < num_blk; j++) {
  

• 		struct dpu_hw_wb *hw_wb;
  

• 		hw_wb = to_dpu_hw_wb(hw_blk[i]);
  

• 		if (hw_wb->idx == phys->intf_idx)
  

• 			phys->hw_wb = hw_wb;
  

• 	}
  

• } else {
  

• 	for (j = 0; j < num_blk; j++) {
  

• 		struct dpu_hw_intf *hw_intf;
  

• 		hw_intf = to_dpu_hw_intf(hw_blk[i]);
  

• 		if (hw_intf->idx == phys->intf_idx)
  

• 			phys->hw_intf = hw_intf;
  

• 	}
  

It appears the original bit of code iterates j from 0 to num_blks yet only uses i as iteration value. All of this code seems reentrant meaning that executing it more than one times is redundant. You've adopted this mistake, though I'd argue it should use j in hw_blk[i] as that follows the number of elements in hw_blk returned by dpu_rm_get_assigned_resources.

I suggest to address this in a separate patch (I can send that too, feel free to add my Reported-by otherwise) and rebase this patch on top of that, substituting i with j here as well. It seems to have been introduced by b954fa6baaca ("drm/msm/dpu: Refactor rm iterator").

- Marijn

}

• if (!phys->hw_intf) {
  

• if (!phys->hw_intf && !phys->hw_wb) {
  DPU_ERROR_ENC(dpu_enc,
  

• 		      "no intf block assigned at idx: %d\n", i);
  

• 		      "no intf or WB block assigned at idx: %d\n", i);
  return;
  

  }

@@ -1224,15 +1241,22 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc) mutex_unlock(&dpu_enc->enc_lock); }

-static enum dpu_intf dpu_encoder_get_intf(struct dpu_mdss_cfg *catalog, +static enum dpu_intf dpu_encoder_get_intf_or_wb(struct dpu_mdss_cfg *catalog, enum dpu_intf_type type, u32 controller_id) { int i = 0;

• for (i = 0; i < catalog->intf_count; i++) {

• if (catalog->intf[i].type == type
  

•     && catalog->intf[i].controller_id == controller_id) {
  

• 	return catalog->intf[i].id;
  

• if (type != INTF_WB) {

• for (i = 0; i < catalog->intf_count; i++) {
  

• 	if (catalog->intf[i].type == type
  

• 		&& catalog->intf[i].controller_id == controller_id) {
  

• 		return catalog->intf[i].id;
  

• 	}
  

• }
  

• } else {

• for (i = 0; i < catalog->wb_count; i++) {
  

• 	if (catalog->wb[i].id == controller_id)
  

• 		return catalog->wb[i].id;
  

  } }

@@ -2096,6 +2120,9 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc, case DRM_MODE_ENCODER_TMDS: intf_type = INTF_DP; break;

• case DRM_MODE_ENCODER_VIRTUAL:

• intf_type = INTF_WB;
  

• break;
  

  }

  WARN_ON(disp_info->num_of_h_tiles < 1);

@@ -2128,11 +2155,11 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc, DPU_DEBUG("h_tile_instance %d = %d, split_role %d\n", i, controller_id, phys_params.split_role);

• phys_params.intf_idx = dpu_encoder_get_intf(dpu_kms->catalog,
  

• phys_params.intf_idx = dpu_encoder_get_intf_or_wb(dpu_kms->catalog,
  										intf_type,
  										controller_id);
  

  if (phys_params.intf_idx == INTF_MAX) {

• 	DPU_ERROR_ENC(dpu_enc, "could not get intf: type %d, id %d\n",
  

• 	DPU_ERROR_ENC(dpu_enc, "could not get intf or wb: type %d, id %d\n",
  			  intf_type, controller_id);
  ret = -EINVAL;
  

  }

-- 2.7.4