[Intel-gfx] [PATCH 03/11] drm/i915: Disable HDCP signalling on transcoder disable

[Ville Syrjälä]

On Fri, Dec 06, 2019 at 08:55:09AM -0500, Sean Paul wrote:
> On Thu, Dec 05, 2019 at 09:33:19PM +0200, Ville Syrjälä wrote:
> > On Tue, Dec 03, 2019 at 12:36:26PM -0500, Sean Paul wrote:
> > > From: Sean Paul <seanpaul at chromium.org>
> > > 
> > > Currently we rely on intel_hdcp_disable() to disable HDCP signalling in
> > > the DDI Function Control register. This patch adds a safety net by also
> > > clearing the bit when we disable the transcoder.
> > > 
> > > Once we have HDCP over MST and disappearing connectors, we want to make
> > > sure that the signalling is truly disabled even if HDCP teardown doesn't
> > > go as planned.
> > 
> > Why wouldn't it go as planned?
> > 
> 
> Because things can fail in weird and wonderful ways on unplug :-)

Not really.

> 
> It's a safety net. I saw this function and figured HDCP signalling should be
> explicitly cleared here as well.

I call it dead and confusing code. If we get here with HDCP still
enabled we have a more serious bug somewhere else.

-- 
Ville Syrjälä
Intel