[PATCH v13 04/18] drm: exynos: dsi: Switch to DSI panel or bridge find helper

[Jagan Teki]

On Tue, Feb 28, 2023 at 5:40 PM Maxime Ripard <maxime at cerno.tech> wrote:
>
> On Mon, Feb 27, 2023 at 08:41:22PM +0100, Marek Vasut wrote:
> > > If we go ahead with no need for DRM-managed helper at the moment, then
> > > find the panel hook in host.attach and then drop 2/18.
> >
> > The panel lookup must happen in .bind/.probe for exynos/imx respectively ,
> > that's really all that is required here. Then you can drop 1,2,3/18 and get
> > this series applied (I hope) .
> >
> > Can you implement just this one change ?
> >
> > There is no need to use drmm_* helper for now, that can be improved later if
> > possible.
>
> Yeah... The drmm helper isn't needed per se, but not using it will
> create a use-after-free pattern that is very easy to miss.
>
> I'd really prefer not to add a new helper that favors an unsafe pattern,
> but the driver seems to have a whole bunch of them anyway so it's not
> really a big deal.
>
> Which also raises another question: if it's code that is only really
> relevant in the context of that driver, why are you creating a helper
> for it in the first place?

I can answer this question as I did add these helpers.

1. DSI-specific helper added since it is a good candidate for
common/helper code, based on the comments in V9 by Marek. V
https://patchwork.kernel.org/project/dri-devel/patch/20221209152343.180139-8-jagan@amarulasolutions.com/

So, I have added this to the common drm_of code in V10.
https://patchwork.kernel.org/project/dri-devel/patch/20221214125907.376148-2-jagan@amarulasolutions.com/

2. DRM-managed discussion was commented on in V11 by you, so from
where all discussion moved.
https://patchwork.kernel.org/project/dri-devel/patch/20230123151212.269082-3-jagan@amarulasolutions.com/

1) helper wouldn't be an unsafe helper as it can reuse many DSI
drivers but 2) helper might be an unsafe helper at the moment.

Jagan.