Re: [Freedreno] [PATCH] drm/msm/dpu: add DSC range checking during resource reservation

[Dmitry Baryshkov]

On 12/04/2023 21:50, Marijn Suijten wrote:
> On 2023-04-12 10:48:18, Abhinav Kumar wrote:
> [..]
> > > The only way to trigger this newly introduced range check is by omitting
> > > the DSC_x constants and manually writing e.g. an out-of-range value 10
> > > here, or setting DSC_NONE.  This is only allowed for interfaces.
> >
> > Correct, its just working on an implicit understanding that the indices
> > in the catalog
>
> .. this sentence appears to be incomplete: what did you want to say? ..
>
> > which might still be right stick to the RM limits.
> >
> > Thats why this is not bad to have.
>
> What do you mean by "RM limits"?  We have constants in the kernel that
> both define the maximum number of blocks in these arrays and a
> predefined set of ids that block can have.  These are all used in
> constant structs in the catalog, so there's nothing "software" or
> SoC-specific limiting about this (except what is available in the
> arrays).
>
> [..]
> > I think kuogee just added this to keep it consistent with other checks
> > present in the RM. So I didnt see any harm with that.
>
> Yep, that's the only reason
>
> > If he did see an issue, i will let him report that here.
>
> If so an out-of-bounds constant was hardcoded in dpu_hw_catalog.c.
>
> > Otherwise, I dont want to spend more time discussing this bounds check
> > when other blocks already have it.
>
> I'll whip up a patch to clear out the extraneous lookup (assuming there
> is no other reason/dependency for it to be there...) and can follow that
> up with removing these range checks of known-good values in `const
> struct` fields.

Yes, please.

> - Marijn

--
With best wishes
Dmitry