Re: [PATCH v6 09/10] drm/msm/dpu: merge DPU_SSPP_SCALER_QSEED3, QSEED3LITE, QSEED4

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On Wed, 1 Nov 2023 at 21:56, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
>
>
>
> On 11/1/2023 12:39 PM, Dmitry Baryshkov wrote:
> > On Wed, 1 Nov 2023 at 20:43, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
> >>
> >>
> >>
> >> On 10/31/2023 1:19 AM, Dmitry Baryshkov wrote:
> >>> On Mon, 30 Oct 2023 at 22:24, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
> >>>>
> >>>>
> >>>>
> >>>> On 10/6/2023 6:14 AM, Dmitry Baryshkov wrote:
> >>>>> Three different features, DPU_SSPP_SCALER_QSEED3, QSEED3LITE and QSEED4
> >>>>> are all related to different versions of the same HW scaling block.
> >>>>> Corresponding driver parts use scaler_blk.version to identify the
> >>>>> correct way to program the hardware. In order to simplify the driver
> >>>>> codepath, merge these three feature bits.
> >>>>>
> >>>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> >>>>> ---
> >>>>>     drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c | 4 ++--
> >>>>>     drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h | 6 +-----
> >>>>>     drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c    | 9 ++-------
> >>>>>     drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c      | 3 +--
> >>>>>     4 files changed, 6 insertions(+), 16 deletions(-)
> >>>>>
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
> >>>>> index 32c396abf877..eb867c8123d7 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
> >>>>> @@ -31,10 +31,10 @@
> >>>>>         (VIG_SDM845_MASK | BIT(DPU_SSPP_SMART_DMA_V2))
> >>>>>
> >>>>>     #define VIG_SC7180_MASK \
> >>>>> -     (VIG_MASK | BIT(DPU_SSPP_QOS_8LVL) | BIT(DPU_SSPP_SCALER_QSEED4))
> >>>>> +     (VIG_MASK | BIT(DPU_SSPP_QOS_8LVL) | BIT(DPU_SSPP_SCALER_QSEED3))
> >>>>>
> >>>>>     #define VIG_SM6125_MASK \
> >>>>> -     (VIG_MASK | BIT(DPU_SSPP_QOS_8LVL) | BIT(DPU_SSPP_SCALER_QSEED3LITE))
> >>>>> +     (VIG_MASK | BIT(DPU_SSPP_QOS_8LVL) | BIT(DPU_SSPP_SCALER_QSEED3))
> >>>>>
> >>>>
> >>>> This merging is coming at a cost of inaccuracy. We are marking sc7180
> >>>> and sm6125 as scaler_qseed3. But they are not. Let me know what you
> >>>> think of below idea instead.
> >>>>
> >>>>>     #define VIG_SC7180_MASK_SDMA \
> >>>>>         (VIG_SC7180_MASK | BIT(DPU_SSPP_SMART_DMA_V2))
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> >>>>> index fc5027b0123a..ba262b3f0bdc 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> >>>>> @@ -51,9 +51,7 @@ enum {
> >>>>>     /**
> >>>>>      * SSPP sub-blocks/features
> >>>>>      * @DPU_SSPP_SCALER_QSEED2,  QSEED2 algorithm support
> >>>>> - * @DPU_SSPP_SCALER_QSEED3,  QSEED3 alogorithm support
> >>>>> - * @DPU_SSPP_SCALER_QSEED3LITE,  QSEED3 Lite alogorithm support
> >>>>> - * @DPU_SSPP_SCALER_QSEED4,  QSEED4 algorithm support
> >>>>> + * @DPU_SSPP_SCALER_QSEED3,  QSEED3 alogorithm support (also QSEED3LITE and QSEED4)
> >>>>>      * @DPU_SSPP_SCALER_RGB,     RGB Scaler, supported by RGB pipes
> >>>>>      * @DPU_SSPP_CSC,            Support of Color space converion
> >>>>>      * @DPU_SSPP_CSC_10BIT,      Support of 10-bit Color space conversion
> >>>>> @@ -72,8 +70,6 @@ enum {
> >>>>>     enum {
> >>>>>         DPU_SSPP_SCALER_QSEED2 = 0x1,
> >>>>>         DPU_SSPP_SCALER_QSEED3,
> >>>>> -     DPU_SSPP_SCALER_QSEED3LITE,
> >>>>> -     DPU_SSPP_SCALER_QSEED4,
> >>>>>         DPU_SSPP_SCALER_RGB,
> >>>>>         DPU_SSPP_CSC,
> >>>>>         DPU_SSPP_CSC_10BIT,
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c
> >>>>> index 7e9c87088e17..d1b70cf72eef 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c
> >>>>> @@ -594,9 +594,7 @@ static void _setup_layer_ops(struct dpu_hw_sspp *c,
> >>>>>                 test_bit(DPU_SSPP_SMART_DMA_V2, &c->cap->features))
> >>>>>                 c->ops.setup_multirect = dpu_hw_sspp_setup_multirect;
> >>>>>
> >>>>> -     if (test_bit(DPU_SSPP_SCALER_QSEED3, &features) ||
> >>>>> -                     test_bit(DPU_SSPP_SCALER_QSEED3LITE, &features) ||
> >>>>> -                     test_bit(DPU_SSPP_SCALER_QSEED4, &features))
> >>>>> +     if (test_bit(DPU_SSPP_SCALER_QSEED3, &features))
> >>>>>                 c->ops.setup_scaler = _dpu_hw_sspp_setup_scaler3;
> >>>>
> >>>> Can we just do sblk->scaler_blk.version >= 0x3000 instead of this
> >>>> merging? That way you can still drop those enums without inaccuracy.
> >>>
> >>> No. QSEED3 from sdm845 has version 1.3, msm8998, sdm660 and sdm630
> >>> have version 1.2.
> >>>
> >>
> >> Ah got it.
> >>
> >> HW versioning is getting harder to generalize with the example you have
> >> given. In my opinion, in that case lets keep these enums intact because
> >> we dont have any other way of knowing the Qseed version otherwise and in
> >> terms of LOC, we are not really saving so much in this change.
> >>
> >> In the prev change I agreed because along with the name and the version,
> >> we could still interpret the version but with compressing the enums into
> >> just QSEED3, this becomes very confusing. So now, in the future if we
> >> have QSEED5 HW, we will have to change this anyway as its LUT
> >> programming can change. So we need this distinction.
> >
> > I'm trying to eliminate them, because they cause more confusion than
> > the bonuses.
> > Currently we have QSEED3  / 3LITE / 4, which are somewhat compatible.
> >
> > We are aiming to support QSEED2 and RGB, which are incompatible with
> > the QSEED3/3lite/4 family programming sequence. So they get their own
> > feature bits (DPU_SSPP_SCALER_QSEED2 and DPU_SSPP_SCALER_RGB).
> >
> > QSEED5-to-be will either be compatible with QSEED3 (and thus can fall
> > into the same bucket) or it will be a different kind of scaler (and
> > will get its own feature).
> >
> > I'm not a fan of DPU_SSPP_SCALER_QSEED3LITE/QSEED4 and I'd like to
> > remove those two bits for the following reasons:
> > - We already encode this info into the scaler version. How should
> > driver behave it it has e.g. version 3.1, but DPU_SSPP_SCALER_QSEED3?
> > Or vice versa: version 1.2 but QSEED4 feature bit? Having a single
> > QSEED3 removes this issue.
> > - Adding QSEED5-compatible-with-QSEED3 requires changing several
> > places which deal with the feature bits and the per-version setup
> > sequence. This seems like an overkill. It is easy to miss one of the
> > places and thus end up with the half-supported scaler
> >
> > I admit, it might not be ideal to use QSEED3 for all scaler versions.
> > I'm open to suggestions on the better name for this feature bit. But I
> > have no doubts that there should be a single feature bit for all
> > QSEED3/3LITE/4 scalers.
> >
>
> hmmm, the concern i had was that from the version the driver doesnt seem
> to know which qseed it is as you rightly pointed out in your earlier
> response with the examples of sdm845, msm8998 etc.
>
> It needs this feature bit to know which qseed version it is to use the
> correct scaler function. If you remove the other two places below, this
> will be the only one left right?
>
> I was thinking of solving this problem with something like
> QSEED3_3LITE_4 but then this is not scalable if QSEED5 is also a variant
> of QSEED3.
>
> After we remove below 2 places, are there more places where we test
> these feature bits?

Hmm, true, this is the only place enumerating them.

> One thing we can perhaps do is move all this feature bit handling to one
> function like dpu_scaler_is_qseed3_compatible() and move these feature
> bits there. That way you will have only one place to change for all the
> code.

What about renaming QSEED3 to QSEED3_COMPATIBLE then? This would leave
us with RGB, QSEED2, QSEED3_COMPATIBLE. The QSEED5-to-be will either
be added as a new entry (and a new scaler function) or it will fall
into the QSEED3_COMPATIBLE bucket.

I'd really like to remove any chance of confusion between QSEEDn and
the scaler_block.version. I think we already had that wrong in several
catalog entries, so let's not walk twice into the same water.

> >> The below two changes seem fine and that way we are eliminating the
> >> usages of the enum and we will end up with only one place using this.
> >>
> >>
> >>>>
> >>>>>
> >>>>>         if (test_bit(DPU_SSPP_CDP, &features))
> >>>>> @@ -629,10 +627,7 @@ int _dpu_hw_sspp_init_debugfs(struct dpu_hw_sspp *hw_pipe, struct dpu_kms *kms,
> >>>>>                         cfg->len,
> >>>>>                         kms);
> >>>>>
> >>>>> -     if (cfg->features & BIT(DPU_SSPP_SCALER_QSEED3) ||
> >>>>> -                     cfg->features & BIT(DPU_SSPP_SCALER_QSEED3LITE) ||
> >>>>> -                     cfg->features & BIT(DPU_SSPP_SCALER_QSEED2) ||
> >>>>> -                     cfg->features & BIT(DPU_SSPP_SCALER_QSEED4))
> >>>>> +     if (sblk->scaler_blk.len)
> >>>>
> >>>> This part seems fine.
> >>>>
> >>>>>                 dpu_debugfs_create_regset32("scaler_blk", 0400,
> >>>>>                                 debugfs_root,
> >>>>>                                 sblk->scaler_blk.base + cfg->base,
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> >>>>> index 43135894263c..ba3ee4ba25b3 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> >>>>> @@ -438,8 +438,7 @@ static void _dpu_plane_setup_scaler3(struct dpu_hw_sspp *pipe_hw,
> >>>>>                         scale_cfg->src_height[i] /= chroma_subsmpl_v;
> >>>>>                 }
> >>>>>
> >>>>> -             if (pipe_hw->cap->features &
> >>>>> -                     BIT(DPU_SSPP_SCALER_QSEED4)) {
> >>>>> +             if (pipe_hw->cap->sblk->scaler_blk.version >= 0x3000) {
> >>>> This is fine too.
> >>>>>                         scale_cfg->preload_x[i] = DPU_QSEED4_DEFAULT_PRELOAD_H;
> >>>>>                         scale_cfg->preload_y[i] = DPU_QSEED4_DEFAULT_PRELOAD_V;
> >>>>>                 } else {
> >>>
> >>>
> >>>
> >
> >
> >



-- 
With best wishes
Dmitry



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