[PATCH 2/2] drm/i915/hdcp: Check mst_port to determine connector type

[Kandpal, Suraj]

> -----Original Message-----
> From: Deak, Imre <imre.deak at intel.com>
> Sent: Friday, May 17, 2024 6:19 PM
> To: Kandpal, Suraj <suraj.kandpal at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; Borah, Chaitanya Kumar
> <chaitanya.kumar.borah at intel.com>; Shankar, Uma
> <uma.shankar at intel.com>; Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>
> Subject: Re: [PATCH 2/2] drm/i915/hdcp: Check mst_port to determine
> connector type
> 
> On Tue, May 07, 2024 at 09:20:37AM +0530, Suraj Kandpal wrote:
> > Check mst_port field in intel_connector to check connector type rather
> > than rely on encoder as it may not be attached to connector at times.
> >
> > Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp_hdcp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> > b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> > index 551c862ed7a6..2edffe62f360 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_hdcp.c
> > @@ -693,7 +693,7 @@ int intel_dp_hdcp_get_remote_capability(struct
> > intel_connector *connector,
> >
> >  	*hdcp_capable = false;
> >  	*hdcp2_capable = false;
> > -	if (!intel_encoder_is_mst(connector->encoder))
> > +	if (!connector->mst_port)
> 
> I suppose this fixes
> https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/10898
> 
> Could you add the Closes: line for it?
> 

Sure Imre will add that.

> Can this function be called for anything else than an MST connector?
> 
> Afaics it's only called from
> 
> intel_connector_info() ->
> 	intel_hdcp_info(..., remote_req = true)
> 
> only for MST connectors, which makes sense since only MST connectors would
> have remote caps. In that case it would be enough to simply remove the
> encoder check which leads to the NULL deref in case the output is disabled.
> 

Right this function is not invoked from anywhere but hdcp_info() since this was 
Created just to have a sense of the actual HDCP capability of remote monitor rather than
having to display the first monitor's HDCP capability and repeating it for the second monitor
specially when in daisy chain setup.

Regards,
Suraj Kandpal

> >  		return -EINVAL;
> >
> >  	aux = &connector->port->aux;
> > --
> > 2.43.2
> >