[Intel-gfx] [PATCH 2/4] drm/i915: II stage HDCP auth for repeater only

[C, Ramalingam]

> -----Original Message-----
> From: Sean Paul [mailto:seanpaul at chromium.org]
> Sent: Friday, January 19, 2018 3:54 AM
> To: C, Ramalingam <ramalingam.c at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; seanpaul at chromium.org;
> daniel.vetter at ffwll.ch; Vivi, Rodrigo <rodrigo.vivi at intel.com>; Sharma,
> Shashank <shashank.sharma at intel.com>
> Subject: Re: [PATCH 2/4] drm/i915: II stage HDCP auth for repeater only
> 
> On Thu, Jan 18, 2018 at 11:18:06AM +0530, Ramalingam C wrote:
> > Second stage of HDCP authentication required only if the HDCP sink is
> > a repeater.
> >
> > This patch imposes above condition on second stage HDCP authentication.
> 
> Hi Ram,
> This is already enforced in intel_hdcp_auth_downstream()

I am not able to locate any check for repeater capability at start of downstream auth.

I am not sure whether you are referring to number of downstream device count check.
That is valid after poll for ksv_fifo ready. We don't want to wait for 5Sec timeout in poll to detect the repeater cap.

And since the caller is handy with the flag for repeater cap, it is best to decide on the call for downstream auth itself.

Thanks
--Ram
> 
> Thanks,
> Sean
> 
> >
> > Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_hdcp.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
> > b/drivers/gpu/drm/i915/intel_hdcp.c
> > index 6ce6559897a6..b48c72cd0906 100644
> > --- a/drivers/gpu/drm/i915/intel_hdcp.c
> > +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> > @@ -493,7 +493,10 @@ static int intel_hdcp_auth(struct intel_digital_port
> *intel_dig_port,
> >  	 * on those as well.
> >  	 */
> >
> > -	return intel_hdcp_auth_downstream(intel_dig_port, shim);
> > +	if (repeater_present)
> > +		return intel_hdcp_auth_downstream(intel_dig_port, shim);
> > +
> > +	return 0;
> >  }
> >
> >  static
> > --
> > 2.7.4
> >
> 
> --
> Sean Paul, Software Engineer, Google / Chromium OS