Re: [PATCH v3 2/2] drm/mediatek: Fix iommu fault during crtc enabling

[CK Hu (胡俊光)]

Hi, Jason:

On Tue, 2023-07-18 at 15:48 +0000, Jason-JH Lin (林睿祥) wrote:
> Hi CK,
> 
> Thanks for the reviews.
> 
> On Fri, 2023-07-14 at 06:57 +0000, CK Hu (胡俊光) wrote:
> > Hi, Jason:
> > 
> > On Mon, 2023-07-10 at 17:32 +0800, Jason-JH.Lin wrote:
> > > OVL layer should not be enabled before crtc is enabled.
> > > The plane_state of drm_atomic_state is not sync to
> > > the plane_state stored in mtk_crtc during crtc enabling,
> > > so just set all planes to disabled.
> > > 
> > > Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek
> > > SoC
> > > MT8173.")
> > > Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > index d40142842f85..51d10e65004e 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > @@ -410,6 +410,9 @@ static int mtk_crtc_ddp_hw_init(struct
> > > mtk_drm_crtc *mtk_crtc)
> > >  		unsigned int local_layer;
> > >  
> > >  		plane_state = to_mtk_plane_state(plane->state);
> > > +
> > > +		/* should not enable layer before crtc enabled */
> > > +		plane_state->pending.enable = false;
> > 
> > All plane has been disable in mtk_drm_crtc_atomic_disable(),
> > doesn't
> > it?
> > 
> 
> Yes, it does.
> 
> But somehow the plane_state get from to_mtk_plane_state(mtk_crtc-
> > planes[i]) is not synced to the plane_state in atomic_state.
> 
> So I think we should disable ovl layer to avoid incorrect plane_state
> applying to OVL HW at the HW init stage.

Do you mean plane_state in atomic_state is correct but it's not synced
to mtk_crtc->planes? If so, the atomic_state is bypassed into
mtk_drm_crtc_atomic_eanble() and you could sync it here.

Regards,
CK 

> 
> Regards,
> Jason-JH.Lin
> 
> 
> > Regards,
> > CK
> > 
> > >  		comp = mtk_drm_ddp_comp_for_plane(crtc, plane,
> > > &local_layer);
> > >  		if (comp)
> > >  			mtk_ddp_comp_layer_config(comp, local_layer,