[PATCH v6 1/6] drm: sun4i: dsi: Drop DRM bind race with bridge attach

[Maxime Ripard]

On Mon, Jan 17, 2022 at 09:12:37PM +0530, Jagan Teki wrote:
> On Mon, Dec 13, 2021 at 10:32 PM Maxime Ripard <maxime at cerno.tech> wrote:
> >
> > On Fri, Dec 10, 2021 at 04:47:06PM +0530, Jagan Teki wrote:
> > > Existing host driver will keep looking for DRM pointer in
> > > sun6i_dsi_attach and defers even if the particular DSI device
> > > is found for the first time. Meanwhile it triggers the bind
> > > callback and gets the DRM pointer and then continues the
> > > sun6i_dsi_attach.
> > >
> > > This makes a deadlock situation if sun6i_dsi_attach is trying
> > > to find the bridge.
> >
> > I'm not sure what you mean by deadlock here, there's no lock involved?
> 
> deadlock parse here for general understanding, where bind is trying to
> attach bridge but drm pointer is not available that point and drm
> pointer will available only when bind done. This is what I'm calling
> as deadlock here.

Have you read:
https://www.kernel.org/doc/html/latest/gpu/drm-kms-helpers.html#special-care-with-mipi-dsi-bridges

Maxime
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