linux-kernel - Re: [PATCH 0/3] drm/msm/dpu: Initialize SSPP scaler version (from register read)

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Message-ID: <CAA8EJpqL-Vsq7dbK7tfJAGgg2_nV463QYv5zgvRLx_8T2bsXxA@mail.gmail.com>
Date:   Thu, 16 Feb 2023 05:02:32 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Marijn Suijten <marijn.suijten@...ainline.org>
Cc:     Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Archit Taneja <architt@...eaurora.org>,
        Chandan Uddaraju <chandanu@...eaurora.org>,
        Sravanthi Kollukuduru <skolluku@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Martin Botka <martin.botka@...ainline.org>,
        Jami Kettunen <jami.kettunen@...ainline.org>,
        phone-devel@...r.kernel.org
Subject: Re: [PATCH 0/3] drm/msm/dpu: Initialize SSPP scaler version (from
 register read)

On Thu, 16 Feb 2023 at 01:02, Marijn Suijten
<marijn.suijten@...ainline.org> wrote:
>
> Random inspection of the SSPP code surfaced that the version field of
> dpu_scaler_blk was never assigned in the catalog, resulting in wrong
> codepaths to be taken within dpu_hw_setup_scaler3 based on a 0 version.
> Rectify this by reading an accurate value from a register (that is not
> equal to the values represented by DPU_SSPP_SCALER_QSEEDx enum
> variants) and deleting dead code around QSEED versioning.
>
> Future changes should likely get rid of the distinction between QSEED3
> and up, as these are now purely determined from the register value.
> Furthermore implementations could look at the scaler subblk .id field
> rather than the SSPP feature bits, which currently hold redundant
> information.
>
> ---
> Marijn Suijten (3):
>       drm/msm/dpu: Read previously-uninitialized SSPP scaler version from hw
>       drm/msm/dpu: Drop unused get_scaler_ver callback from SSPP
>       drm/msm/dpu: Drop unused qseed_type from catalog dpu_caps

The cleanup looks good. However as you are on it, maybe you can also
add patch 4, dropping DPU_SSPP_SCALER_QSEED3LITE and
DPU_SSPP_SCALER_QSEED4 in favour of using QSEED3 for all these
scalers? As we are going to use scaler_version to distinguish between
them, it would be logical not to duplicate that bit of information
(not to mention all the possible troubles if scaler_version disagrees
with the sblk->scaler_blk.id).

>
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c | 12 ------------
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h |  4 ----
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.c    | 12 ++++++++----
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_sspp.h    |  9 +++------
>  4 files changed, 11 insertions(+), 26 deletions(-)
> ---
> base-commit: 9d9019bcea1aac7eed64a1a4966282b6b7b141c8
> change-id: 20230215-sspp-scaler-version-19f221585c5e
>
> Best regards,
> --
> Marijn Suijten <marijn.suijten@...ainline.org>
>


-- 
With best wishes
Dmitry