Wayland content-protection extension

[Matt Hoosier]

On Mon, Jun 18, 2018 at 8:54 AM Pekka Paalanen <ppaalanen at gmail.com> wrote:

> Hi Matt,
>
> did you intend to reply on list? Please CC if you did.
>
> On Mon, 18 Jun 2018 08:35:56 -0500
> Matt Hoosier <matt.hoosier at gmail.com> wrote:
>
> > On Mon, Jun 18, 2018 at 3:59 AM Pekka Paalanen <ppaalanen at gmail.com>
> wrote:
> >
> > > On Mon, 18 Jun 2018 13:38:09 +0530
> > > Ramalingam C <ramalingam.c at intel.com> wrote:
> > >
> > > > On Monday 18 June 2018 01:34 PM, Pekka Paalanen wrote:
> > > > > On Sat, 16 Jun 2018 12:50:52 +0530
> > > > > Ramalingam C <ramalingam.c at intel.com> wrote:
> > > > >
> > >
> > > > > How does the kernel signal to userspace that the HDCP status has
> > > > > changed? Do you piggyback on the hotplug event?
> > > > >
> > > > > Anything that would require userspace to repeatedly re-read
> properties
> > > > > without any events triggering it is bad design. If nothing is
> > > > > happening, the compositor needs to be able to stay asleep.
> > > > Pekka,
> > > >
> > > > We proposed a uevent from kernel for indicating the HDCP status
> change.
> > > > But that didn't fly. Right now the merged interface expects
> compositor
> > > > to poll
> > > > the property state for the runtime failures.
> > >
> > > Ugh. :-(
> > >
> >
> > I get what you mean here, but maybe it's not actually that bad. The HDCP
> > runtime failure polling would really only be needed during times when at
> > least one video stream is actually using it, right? If that's true, then
> > the compositor is regularly waking up as the clients submit successive
> > buffers anyway. Can the HDCP connector status polling get folded into
> that
> > wakeup cycle?
>
> Sure, but you are assuming the protected content is video. I'm thinking
> of still images.
>

Yeah, that's a fair point. Still probably covers the dominant use-case
though? Just curious, are you referring to the still images that result
from pausing a video stream, or first-class static images (maybe photos or
something) covered by content protection too?


>
> I'd ask for more details on why the kernel community thinks that there
> must not be an event to signal HDCP state changes, I suspect it's a
> problem with the implementation and not the idea, but I won't have time
> to go there anyway.
>
>
> Thanks,
> pq
>
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