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

[Abhinav Kumar <quic_abhinavk@quicinc.com>]

Hi Marijn

Thank you for your suggestion.
I will address it and add your "Reported by".

Thanks

Abhinav

On 4/14/2022 3:26 PM, Marijn Suijten wrote:
> 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
>>