[PATCH 04/11] drm/i915: Don't WARN on HDCP toggle if get_hw_state returns false

[Sean Paul]

On Mon, Dec 9, 2019 at 10:21 AM Ville Syrjälä
<ville.syrjala at linux.intel.com> wrote:
>
> On Fri, Dec 06, 2019 at 08:52:33AM -0500, Sean Paul wrote:
> > On Thu, Dec 05, 2019 at 09:39:35PM +0200, Ville Syrjälä wrote:
> > > On Tue, Dec 03, 2019 at 12:36:27PM -0500, Sean Paul wrote:
> > > > From: Sean Paul <seanpaul at chromium.org>
> > > >
> > > > Now that we can rely on transcoder disable to toggle signalling off,
> > > > it's less of a catastrophe if get_hw_state() returns false.
> > > >
> > > > Once we enable MST, this will be a valid exit path and we want to make
> > > > sure we're not spamming the logs needlessly.
> > > >
> > > > Signed-off-by: Sean Paul <seanpaul at chromium.org>
> > > > ---
> > > >  drivers/gpu/drm/i915/display/intel_ddi.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> > > > index e8ac98a8ee7f..ca28913a4c9f 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > > > @@ -1983,7 +1983,7 @@ int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
> > > >   if (WARN_ON(!wakeref))
> > > >           return -ENXIO;
> > > >
> > > > - if (WARN_ON(!intel_encoder->get_hw_state(intel_encoder, &pipe))) {
> > > > + if (!intel_encoder->get_hw_state(intel_encoder, &pipe)) {
> > >
> > > How can this get called when the encoder is not enabled?
> > > Feels like this whole thing is trying to paper over some
> > > bigger bug in the hdcp code.
> >
> > In the MST patch, I've added a call to intel_hdcp_disable() in the connector
> > destroy path. Usually toggling will be disabled as part of the check_link call
> > that is initiated on unplug, so in the destroy path it's non-essential to do
> > this again.
>
> Can't we just leave things be until userspace disables the thing?

The connector disappears, so userspace won't be able to disable it.

> If not, then we should know whether hdcp is still enabled. And if
> hdcp is enabled so is the encoder, thus we don't need such silly
> checks.

Alright, I'll look at taking this angle.

Sean

>
> --
> Ville Syrjälä
> Intel