Re: [PATCH] drm/msm: Initialize mode_config earlier

[Dmitry Baryshkov]

On 13/01/2023 06:23, Dmitry Baryshkov wrote:
> On 13/01/2023 06:10, Bjorn Andersson wrote:
> > Invoking drm_bridge_hpd_notify() on a drm_bridge with a HPD-enabled
> > bridge_connector ends up in drm_bridge_connector_hpd_cb() calling
> > drm_kms_helper_hotplug_event(), which assumes that the associated
> > drm_device's mode_config.funcs is a valid pointer.
> >
> > But in the MSM DisplayPort driver the HPD enablement happens at bind
> > time and mode_config.funcs is initialized late in msm_drm_init(). This
> > means that there's a window for hot plug events to dereference a NULL
> > mode_config.funcs.
> >
> > Move the assignment of mode_config.funcs before the bind, to avoid this
> > scenario.
>
> Cam we make DP driver not to report HPD events until the enable_hpd() 
> was called? I think this is what was fixed by your internal_hpd patchset.

Or to express this in another words: I thought that internal_hpd already 
deferred enabling hpd event reporting till the time when we need it, 
didn't it?


--
With best wishes
Dmitry