Re: [Intel-gfx] [PATCH 1/4] drm/i915/hdcp: Update CP as per the kernel internal state

[Anshuman Gupta <anshuman.gupta@intel.com>]

On 2020-03-04 at 09:43:10 +0100, Maarten Lankhorst wrote:
> Op 03-03-2020 om 17:35 schreef Anshuman Gupta:
> > On 2020-03-03 at 15:36:37 +0100, Maarten Lankhorst wrote:
> >> Op 05-02-2020 om 06:07 schreef Anshuman Gupta:
> >>> On 2020-01-28 at 21:45:45 +0530, Anshuman Gupta wrote:
> >>> Hi Jani ,
> >>> As per my understanding intel_hdcp_atomic_check() is not sufficient to
> >>> fix the broken hdcp uapi state, as the state fixup required in case
> >>> of modeset.
> >>> If you do not have any concern, can we continue with the patch.
> >>> Thanks,
> >>> Anshuman Gupta.
> >> Hey,
> >>
Hi Maarten,
> > Thanks martin for review. 
My apology for typo here.
> > As full modeset DDI disable sequence  (encoder->disable()->intel_hdcp_disable()) can cause HDCP to 
> > disable without user space knowledge i.e. when Content Protetion state is not UNDESIRED, in those cases
> > we want to fix the HDCP Content Protection state.  
> You can get to crtc_state from the connector_state->crtc, should be easy to fix up this case.
> >> In case of a modeset, don't we always call atomic_check() on the connector, either before or after?
> > yes it calls drm_atomic_helper_check_modeset()->intel_digital_connector_atomic_check()->intel_hdcp_atomic_check(),
> > but if we fix HDCP state in intel_hdcp_atomic_check(), there may be a case at later point that fastset 
> > check is true, which disable need_modeset and enable update_pipe due to which encoder->update_pipe()->intel_hdcp_update_pipe()
> > may endup enabling HDCP again when HDCP is already enabled, which is wrong.
> 
> Seems that if you look at the crtc_state carefully, you can prevent that. :)
If i understand correctly your suggestion to use crtc_state->active state here,
or it is some other crtc state parameter to refer.
AFAIU crtc_state->active state can also be true for any modeset request,
Please correct me if i am wrong here.
Thanks,
Anshuman.
> 
> 
> ~Maarten
> 
> >> Should be fine to fixup there then?
> > Therefore we want to fixup the HDCP state only when full modeset is required, when it is going
> > to disable DDI.
> >
> > Thanks ,
> > Anshuman Gupta.
> >>>> On 2020-01-28 at 21:14:44 +0530, Anshuman Gupta wrote:
> >>>>> On 2020-01-28 at 16:19:31 +0200, Jani Nikula wrote:
> >>>>>> On Tue, 28 Jan 2020, Anshuman Gupta <anshuman.gupta@intel.com> wrote:
> >>>>>>> Content Protection property should be updated as per the kernel
> >>>>>>> internal state. Let's say if Content protection is disabled
> >>>>>>> by userspace, CP property should be set to UNDESIRED so that
> >>>>>>> reauthentication will not happen until userspace request it again,
> >>>>>>> but when kernel disables the HDCP due to any DDI disabling sequences
> >>>>>>> like modeset/DPMS operation, kernel should set the property to
> >>>>>>> DESIRED, so that when opportunity arises, kernel will start the
> >>>>>>> HDCP authentication on its own.
> >>>>>>>
> >>>>>>> Somewhere in the line, state machine to set content protection to
> >>>>>>> DESIRED from kernel was broken and IGT coverage was missing for it.
> >>>>>>> This patch fixes it.
> >>>>>>> IGT patch to catch further regression on this features is being
> >>>>>>> worked upon.
> >>>>>>>
> >>>>>>> CC: Ramalingam C <ramalingam.c@intel.com>
> >>>>>>> Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
> >>>>>>> ---
> >>>>>>>  drivers/gpu/drm/i915/display/intel_display.c |  4 +++
> >>>>>>>  drivers/gpu/drm/i915/display/intel_hdcp.c    | 26 ++++++++++++++++++++
> >>>>>>>  drivers/gpu/drm/i915/display/intel_hdcp.h    |  2 ++
> >>>>>>>  3 files changed, 32 insertions(+)
> >>>>>>>
> >>>>>>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> >>>>>>> index da5266e76738..934cdf1f1858 100644
> >>>>>>> --- a/drivers/gpu/drm/i915/display/intel_display.c
> >>>>>>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> >>>>>>> @@ -14595,6 +14595,10 @@ static int intel_atomic_check(struct drm_device *dev,
> >>>>>>>  		goto fail;
> >>>>>>>  
> >>>>>>>  	if (any_ms) {
> >>>>>>> +		/*
> >>>>>>> +		 * When there is modeset fix the hdcp uapi CP state.
> >>>>>>> +		 */
> >>>>>>> +		intel_hdcp_post_need_modeset_check(state);
> >>>>>>>  		ret = intel_modeset_checks(state);
> >>>>>>>  		if (ret)
> >>>>>>>  			goto fail;
> >>>>>>> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> >>>>>>> index 0fdbd39f6641..be083136eee2 100644
> >>>>>>> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> >>>>>>> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> >>>>>>> @@ -2074,6 +2074,32 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
> >>>>>>>  	crtc_state->mode_changed = true;
> >>>>>>>  }
> >>>>>>>  
> >>>>>>> +/**
> >>>>>>> + * intel_hdcp_post_need_modeset_check.
> >>>>>>> + * @state: intel atomic state.
> >>>>>>> + *
> >>>>>>> + * This function fix the HDCP uapi state when hdcp disabling initiated from
> >>>>>>> + * modeset DDI disabling sequence. It updates uapi CP state from ENABLED to
> >>>>>>> + * DESIRED so that HDCP uapi state can be restored as per HDCP Auth state.
> >>>>>>> + * This function should be called only in case of in case of modeset.
> >>>>>>> + * FIXME: As per HDCP content protection property uapi doc, an uevent()
> >>>>>>> + * need to be sent if there is transition from ENABLED->DESIRED.
> >>>>>>> + */
> >>>>>>> +void intel_hdcp_post_need_modeset_check(struct intel_atomic_state *state)
> >>>>>>> +{
> >>>>>>> +	struct drm_connector *connector;
> >>>>>>> +	struct drm_connector_state *old_state;
> >>>>>>> +	struct drm_connector_state *new_state;
> >>>>>>> +	int i;
> >>>>>>> +
> >>>>>>> +	for_each_oldnew_connector_in_state(&state->base, connector, old_state,
> >>>>>>> +					   new_state, i) {
> >>>>>>> +		if (old_state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED &&
> >>>>>>> +		    new_state->content_protection != DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
> >>>>>>> +			new_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
> >>>>>>> +	}
> >>>>>>> +}
> >>>>>>> +
> >>>>>> Why does this feel like duplication of what you already have in
> >>>>>> intel_hdcp_atomic_check()?
> >>>>> intel_hdcp_atomic_check() have checks that for disconnected connector and it doesn't look for 
> >>>> typo here, "intel_hdcp_atomic_check() checks that for disconnected connector and it doesn't check for new state shouldn't be UNDESIRED" 
> >>>>> old state, that is not sufficient to fix the hdcp CP uapi state, it need to be fix only in case of
> >>>>> modeset, Later on a fastset check can disable the modeset and we would endup calling intel_hdcp_enable
> >>>>> while hdcp is already enabled. That is the reason i think we would require a new API to
> >>>>> fix the uapi state.
> >>>>> Thanks ,
> >>>>> Anshuman Gupta.
> >>>>>> BR,
> >>>>>> Jani.
> >>>>>>
> >>>>>>
> >>>>>>>  /* Handles the CP_IRQ raised from the DP HDCP sink */
> >>>>>>>  void intel_hdcp_handle_cp_irq(struct intel_connector *connector)
> >>>>>>>  {
> >>>>>>> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.h b/drivers/gpu/drm/i915/display/intel_hdcp.h
> >>>>>>> index f3c3272e712a..7bf46bc3c348 100644
> >>>>>>> --- a/drivers/gpu/drm/i915/display/intel_hdcp.h
> >>>>>>> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.h
> >>>>>>> @@ -13,6 +13,7 @@
> >>>>>>>  struct drm_connector;
> >>>>>>>  struct drm_connector_state;
> >>>>>>>  struct drm_i915_private;
> >>>>>>> +struct intel_atomic_state;
> >>>>>>>  struct intel_connector;
> >>>>>>>  struct intel_hdcp_shim;
> >>>>>>>  enum port;
> >>>>>>> @@ -21,6 +22,7 @@ enum transcoder;
> >>>>>>>  void intel_hdcp_atomic_check(struct drm_connector *connector,
> >>>>>>>  			     struct drm_connector_state *old_state,
> >>>>>>>  			     struct drm_connector_state *new_state);
> >>>>>>> +void intel_hdcp_post_need_modeset_check(struct intel_atomic_state *state);
> >>>>>>>  int intel_hdcp_init(struct intel_connector *connector,
> >>>>>>>  		    const struct intel_hdcp_shim *hdcp_shim);
> >>>>>>>  int intel_hdcp_enable(struct intel_connector *connector,
> >>>>>> -- 
> >>>>>> Jani Nikula, Intel Open Source Graphics Center
> >>> _______________________________________________
> >>> Intel-gfx mailing list
> >>> Intel-gfx@lists.freedesktop.org
> >>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >>>
> 
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