[Intel-gfx] i915 MST HDCP code looks broken

[Gupta, Anshuman]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: Monday, October 4, 2021 4:22 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Sean Paul <seanpaul at chromium.org>; Gupta, Anshuman
> <anshuman.gupta at intel.com>; C, Ramalingam <ramalingam.c at intel.com>; B S,
> Karthik <karthik.b.s at intel.com>
> Subject: i915 MST HDCP code looks broken
> 
> Hi,
> 
> I took a quick peek at intel_dp_add_mst_connector() the other day and noticed
> that it calls intel_dp_hdcp_init() and passes in the SST dig_port. And digging in a
> bit further that seems to clobber all kinds of things in dig_port->hdcp_port_data.
> This looks rather broken to me.
> 
> So has anyone actually thought what happens if you first use MST on the port,
> and then later switch to SST on the same port?
AFAIU there shouldn't be , when the last connector of MST topology get destroyed  and it switches to SST mode on same port.
The base static connector of same dig_port should get connected and will call  intel_dp_init_connector()->intel_dp_hdcp_init().
What is the specific sequence is broken here , is it the connector destroy path ? 
> --
> Ville Syrjälä
> Intel