Re: [PATCH v2 02/12] drm/i915: Clear the repeater bit on HDCP disable

[Sean Paul <sean@poorly.run>]

On Fri, Dec 13, 2019 at 03:59:02PM +0530, Ramalingam C wrote:
> On 2019-12-12 at 14:02:20 -0500, Sean Paul wrote:
> > From: Sean Paul <seanpaul@chromium.org>
> > 
> > On HDCP disable, clear the repeater bit. This ensures if we connect a
> > non-repeater sink after a repeater, the bit is in the state we expect.
> > 
> > Fixes: ee5e5e7a5e0f ("drm/i915: Add HDCP framework + base implementation")
> > Cc: Chris Wilson <chris@chris-wilson.co.uk>
> > Cc: Ramalingam C <ramalingam.c@intel.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Sean Paul <seanpaul@chromium.org>
> > Cc: Jani Nikula <jani.nikula@linux.intel.com>
> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Cc: intel-gfx@lists.freedesktop.org
> > Cc: <stable@vger.kernel.org> # v4.17+
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > 
> > Changes in v2:
> > -Added to the set
> > ---
> >  drivers/gpu/drm/i915/display/intel_hdcp.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > index eaab9008feef..c4394c8e10eb 100644
> > --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > @@ -773,6 +773,7 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
> >  	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
> >  	enum port port = intel_dig_port->base.port;
> >  	enum transcoder cpu_transcoder = hdcp->cpu_transcoder;
> > +	u32 repeater_ctl;
> >  	int ret;
> >  
> >  	DRM_DEBUG_KMS("[%s:%d] HDCP is being disabled...\n",
> > @@ -787,6 +788,10 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
> >  		return -ETIMEDOUT;
> >  	}
> >  
> > +	repeater_ctl = intel_hdcp_get_repeater_ctl(dev_priv, cpu_transcoder,
> > +						   port);
> > +	I915_WRITE(HDCP_REP_CTL, I915_READ(HDCP_REP_CTL) & ~repeater_ctl);
> Do you think it will help to (double) clear HDCP_REP_CTL when detect a
> sink which is non repeater!? But yes disable will be executed on all
> HDCP exits.
> 

Yeah, that's probably a better idea. I was a little undecided on where to put it
and I think I settled on the disable path since that matches the way we handle
HDCP signalling. However if we always write REP_CTL, that cuts our callsites
back down to 1, which seems like a Good Thing.

Will revise.

Sean

> > +
> LGTM
> 
> Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
> 
> >  	ret = hdcp->shim->toggle_signalling(intel_dig_port, false);
> >  	if (ret) {
> >  		DRM_ERROR("Failed to disable HDCP signalling\n");
> > -- 
> > Sean Paul, Software Engineer, Google / Chromium OS
> > 

-- 
Sean Paul, Software Engineer, Google / Chromium OS