On Fri, 15 Nov 2024, Imre Deak <imre.d...@intel.com> wrote:
> The connector initialization in intel_dp_add_mst_connector() depends on
> the device pointer in connector to be valid, at least by connector
> debug printing. The device pointer is initialized by drm_connector_init(),
> however that function also exposes the connector to in-kernel users,
> which can't be done before the connector is fully initialized. For now
> make sure the device pointer is valid before it's used, until a
> follow-up change moving this to DRM core.
>
> This issue was revealed by the commit in the Fixes: line below, before
> which the above debug printing checked and handled a NULL device pointer
> gracefully in DRM core.
>
> Cc: Jani Nikula <jani.nik...@intel.com>
> Fixes: 529798bd786a ("drm/i915/mst: convert to struct intel_display")
> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12799
> Signed-off-by: Imre Deak <imre.d...@intel.com>I think you should send this patch alone to intel-gfx and intel-xe to address the regression. The others can follow later, and likely be merged via drm-misc. I have some comments about them, but I don't want to block fixing the issue. BR, Jani. > --- > drivers/gpu/drm/i915/display/intel_dp_mst.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c > b/drivers/gpu/drm/i915/display/intel_dp_mst.c > index df7edcfe885b6..f058360a26413 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c > @@ -1727,6 +1727,16 @@ static struct drm_connector > *intel_dp_add_mst_connector(struct drm_dp_mst_topolo > > intel_dp_init_modeset_retry_work(intel_connector); > > + /* > + * TODO: The following drm_connector specific initialization belongs > + * to DRM core, however it happens atm too late in > + * drm_connector_init(). That function will also expose the connector > + * to in-kernel users, so it can't be called until the connector is > + * sufficiently initialized; init the device pointer used by the > + * following DSC setup, until a fix moving this to DRM core. > + */ > + intel_connector->base.dev = mgr->dev; > + > intel_connector->dp.dsc_decompression_aux = > drm_dp_mst_dsc_aux_for_port(port); > intel_dp_mst_read_decompression_port_dsc_caps(intel_dp, > intel_connector); > intel_connector->dp.dsc_hblank_expansion_quirk = -- Jani Nikula, Intel
