Re: [Intel-gfx] i915 MST HDCP code looks broken
On Mon, Oct 04, 2021 at 03:04:01PM +, Gupta, Anshuman wrote: > > > > -Original Message- > > From: Ville Syrjälä > > Sent: Monday, October 4, 2021 4:22 PM > > To: intel-gfx@lists.freedesktop.org > > Cc: Sean Paul ; Gupta, Anshuman > > ; C, Ramalingam ; B S, > > Karthik > > 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
Re: [Intel-gfx] i915 MST HDCP code looks broken
> -Original Message- > From: Ville Syrjälä > Sent: Monday, October 4, 2021 4:22 PM > To: intel-gfx@lists.freedesktop.org > Cc: Sean Paul ; Gupta, Anshuman > ; C, Ramalingam ; B S, > Karthik > 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
[Intel-gfx] 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? -- Ville Syrjälä Intel
