[Intel-gfx] i915 MST HDCP code looks broken

[Ville Syrjälä]

On Mon, Oct 04, 2021 at 03:04:01PM +0000, Gupta, Anshuman wrote:
> 
> 
> > -----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().

SST conectors are static. They are created exactly once when the driver
loads.

-- 
Ville Syrjälä
Intel