Re: [REPOST PATCH v4 08/13] drm/msm/disp/dpu1: Don't use DSC with mode_3d

Dmitry Baryshkov
2022-02-17T07:12:29Z

On 17/02/2022 09:33, Abhinav Kumar wrote:
>
>
> On 2/16/2022 10:10 PM, Vinod Koul wrote:
>> On 16-02-22, 19:11, Abhinav Kumar wrote:
>>>
>>>
>>> On 2/10/2022 2:34 AM, Vinod Koul wrote:
>>>> We cannot enable mode_3d when we are using the DSC. So pass
>>>> configuration to detect DSC is enabled and not enable mode_3d
>>>> when we are using DSC
>>>>
>>>> We add a helper dpu_encoder_helper_get_dsc() to detect dsc
>>>> enabled and pass this to .setup_intf_cfg()
>>>>
>>>> Signed-off-by: Vinod Koul <vkoul@kernel.org>
>>>
>>> We should not use 3D mux only when we use DSC merge topology.
>>> I agree that today we use only 2-2-1 topology for DSC which means its
>>> using
>>> DSC merge.
>>>
>>> But generalizing that 3D mux should not be used for DSC is not right.
>>>
>>> You can detect DSC merge by checking if there are two encoders and one
>>> interface in the topology and if so, you can disable 3D mux.
>>
>> Right now with DSC we disable that as suggested by Dmitry last time.
>> Whenever we introduce merge we should revisit this, for now this should
>> suffice
>>
>
> Sorry I didnt follow.
>
> The topology which you are supporting today IS DSC merge 2-2-1. I didnt
> get what you mean by "whenever we introduce".
>
> I didnt follow Dmitry's comment either.
>
> "anybody adding support for SDE_RM_TOPOLOGY_DUALPIPE_3DMERGE_DSC handle
> this."
>
> 3D mux shouldnt be used when DSC merge is used.
>
> The topology Dmitry is referring to will not use DSC merge but you are
> using it here and thats why you had to make this patch in the first
> place. So I am not sure why would someone who uses 3D merge topology
> worry about DSC merge. Your patch is the one which deals with the
> topology in question.
>
> What I am suggesting is a small but necessary improvement to this patch.

It seems that we can replace this patch by changing
dpu_encoder_helper_get_3d_blend_mode() to contain the following
condition (instead of the one present there). Does the following seem
correct to you:

static inline enum dpu_3d_blend_mode dpu_encoder_helper_get_3d_blend_mode(
struct dpu_encoder_phys *phys_enc)
{
struct dpu_crtc_state *dpu_cstate;

if (!phys_enc || phys_enc->enable_state == DPU_ENC_DISABLING)
return BLEND_3D_NONE;

dpu_cstate = to_dpu_crtc_state(phys_enc->parent->crtc->state);

+ /* Use merge_3d unless DSCMERGE topology is used */
if (phys_enc->split_role == ENC_ROLE_SOLO &&
+ hweight(dpu_encoder_helper_get_dsc(phys_enc)) != 1 &&
dpu_cstate->num_mixers == CRTC_DUAL_MIXERS)
return BLEND_3D_H_ROW_INT;

return BLEND_3D_NONE;
}

>
> All that you have to do is in query whether DSC merge is used from the
> topology. You can do it in multiple ways:
>
> 1) Either query this from the encoder
> 2) Store a bool "dsc_merge" in the intf_cfg
>

--
With best wishes
Dmitry