On Fri, Feb 02, 2018 at 07:42:47PM +0530, Ramalingam C wrote: > > > On Friday 02 February 2018 07:43 PM, Sean Paul wrote: > > On Fri, Feb 02, 2018 at 04:15:14PM +0530, Ramalingam C wrote: > > > If a HDCP repeater is detected with zero hdcp authenticated > > > downstream devices, there are two option as below: > > > > > > 1. Dont continue on second stage authentication. Disable encryption. > > > 2. Continue with second stage authentication excluding the KSV list and > > > continue encryption on success. > > > > > > This patch adopts the option 1. > > It doesn't seem that hard to adopt option 2 and avoid failure. That would result > > in a better experience. > True. Not too much effort for option 2. But I am not seeing any ROI out of > it at this point. > what is the benefit of encrypting if repeater cant use it, as it has 0 sinks > attached to it. > Still do we want option two? Is it possible the repeater itself has video output? I'm also worried about non-compliant displays which may report having a repeater. If these aren't possible, I agree. Just beef up the comment like "If there are no downstream devices, spec requires we disable all encryption. So fail here to ensure hdcp is disabled" Sean > > -Ram > > > > > Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx> > > > --- > > > drivers/gpu/drm/i915/intel_hdcp.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c > > > index 0021511ae4d7..182a3c8a4e4a 100644 > > > --- a/drivers/gpu/drm/i915/intel_hdcp.c > > > +++ b/drivers/gpu/drm/i915/intel_hdcp.c > > > @@ -175,10 +175,10 @@ int intel_hdcp_auth_downstream(struct intel_connector *connector) > > > return -EPERM; > > > } > > > - /* If there are no downstream devices, we're all done. */ > > > + /* If there are no downstream devices, we're not encrypting. */ > > > num_downstream = DRM_HDCP_NUM_DOWNSTREAM(bstatus[0]); > > > if (num_downstream == 0) > > > - return 0; > > > + return -EINVAL; > > > ksv_fifo = kzalloc(num_downstream * DRM_HDCP_KSV_LEN, GFP_KERNEL); > > > if (!ksv_fifo) > > > -- > > > 2.7.4 > > > > -- Sean Paul, Software Engineer, Google / Chromium OS _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
