linux-kernel - Re: [PATCH v27 6/7] drm/mediatek: add drm ovl

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Date:   Fri, 4 Nov 2022 10:57:28 +0000
From:   Nancy Lin (林欣螢) <Nancy.Lin@...iatek.com>
To:     "nfraprado@...labora.com" <nfraprado@...labora.com>
CC:     "llvm@...ts.linux.dev" <llvm@...ts.linux.dev>,
        Yongqiang Niu (牛永强) 
        <yongqiang.niu@...iatek.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        Singo Chang (張興國) 
        <Singo.Chang@...iatek.com>,
        "nathan@...nel.org" <nathan@...nel.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>,
        Jason-JH Lin (林睿祥) 
        <Jason-JH.Lin@...iatek.com>,
        "linux@...ck-us.net" <linux@...ck-us.net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        Project_Global_Chrome_Upstream_Group 
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        "wim@...ux-watchdog.org" <wim@...ux-watchdog.org>,
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        "airlied@...ux.ie" <airlied@...ux.ie>,
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        <angelogioacchino.delregno@...labora.com>,
        "ndesaulniers@...gle.com" <ndesaulniers@...gle.com>
Subject: Re: [PATCH v27 6/7] drm/mediatek: add drm ovl_adaptor sub driver for
 MT8195

Dear Nicolas,

Thanks for the review.

On Thu, 2022-11-03 at 17:28 -0400, Nícolas F. R. A. Prado wrote:
> On Thu, Nov 03, 2022 at 11:26:09AM +0800, Nancy.Lin wrote:
> > Add drm ovl_adaptor sub driver. Bring up ovl_adaptor sub driver if
> > the component exists in the path.
> > 
> > Signed-off-by: Nancy.Lin <nancy.lin@...iatek.com>
> > Reviewed-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@...labora.com>
> > Reviewed-by: CK Hu <ck.hu@...iatek.com>
> > Tested-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@...labora.com>
> > Tested-by: Bo-Chen Chen <rex-bc.chen@...iatek.com>
> > Tested-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
> > Change-Id: I0501f3c80e78ec8279366cba9c137a2edd7a852e
> > ---
> >  drivers/gpu/drm/mediatek/mtk_drm_crtc.c     |  61 ++++-----
> >  drivers/gpu/drm/mediatek/mtk_drm_crtc.h     |   2 +-
> >  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 129 ++++++++++++--
> > ------
> >  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |  50 +++++++-
> >  drivers/gpu/drm/mediatek/mtk_drm_drv.c      |  78 ++++++------
> >  drivers/gpu/drm/mediatek/mtk_drm_drv.h      |  12 +-
> >  6 files changed, 209 insertions(+), 123 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > index 30dcb65d8a5a..ce5617ad04cb 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> 
> [..]
> >  int mtk_drm_crtc_create(struct drm_device *drm_dev,
> > -			const enum mtk_ddp_comp_id *path, unsigned int
> > path_len,
> > +			const unsigned int *path, unsigned int
> > path_len,
> 
> Hi Nancy,
> 
> why is 'enum mtk_ddp_comp_id' being changed to 'unsigned int'
> throughout this
> patch? Was this intentional?
> 
> I saw that this change happened between v16 [1] and v17 [2], but I
> didn't see
> any reply or mention about this in the commit message or cover
> letter.
> 
> Thanks,
> Nícolas
> 
> [1] 
> https://lore.kernel.org/all/20220318142009.2796-21-nancy.lin@mediatek.com/
> [2] 
> https://lore.kernel.org/all/20220416020749.29010-20-nancy.lin@mediatek.com/


The change is for the review in [1] to expose each mod instead of ovl
adaptor to mtk_mutex.
Ovl adaptor is an application that combine these mod to achieve ovl
function, and it's not a real component in mtk_mmsys/mtk_mutex.

For the above comment, I discussed the solution with MediaTek DRM
reviewer CK.Hu internally.
1. remove the DDP_COMPONENT_OVL_ADAPTOR in enum mtk_ddp_comp_id{}  (ref
[2])
2. add DRM driver component define "DDP_COMPONENT_DRM_OVL_ADAPTOR" in
mtk_drm_drv.h (ref[3])
3. replace mmsys compoent DDP_COMPONENT_OVL_ADAPTOR with DRM driver
compoent DDP_COMPONENT_DRM_OVL_ADAPTOR in drm mt8195_mtk_ddp_ext[] path
array. (ref[3] - mtk_drm_drv.c)
   
    static const unsigned int mt8195_mtk_ddp_ext[] = {
		DDP_COMPONENT_DRM_OVL_ADAPTOR,
		DDP_COMPONENT_MERGE5,
		DDP_COMPONENT_DP_INTF1,
    };
Because the DDP_COMPONENT_DRM_OVL_ADAPTOR is not a real mmsys
component, change to use "unsigned int" instead of "enum
mtk_ddp_comp_id{}"


[1] 
https://patchwork.kernel.org/project/linux-mediatek/patch/20220318142009.2796-10-nancy.lin@mediatek.com/
[2] 
https://patchwork.kernel.org/project/linux-mediatek/patch/20220318142009.2796-5-nancy.lin@mediatek.com/
[3] 
https://patchwork.kernel.org/project/linux-mediatek/patch/20221103032610.9217-7-nancy.lin@mediatek.com/

Thanks,
Nancy