On Mon, 20 Jan 2020, Ramalingam C <ramalingam.c@xxxxxxxxx> wrote:
> On 2020-01-20 at 11:19:54 +0530, Anshuman Gupta 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.
>>
>> v2:
>> - Incorporated the necessary locking. (Ram)
>> - Set content protection property to CP_DESIRED only when
>> user has not asked explicitly to set CP_UNDESIRED.
>>
>> v3:
>> - Reset the is_hdcp_undesired flag to false. (Ram)
>> - Rephrasing commit log and small comment for is_hdcp_desired
>> flag. (Ram)
>>
>> CC: Ramalingam C <ramalingam.c@xxxxxxxxx>
>> Reviewed-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
>> Signed-off-by: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/display/intel_display_types.h | 6 ++++++
>> drivers/gpu/drm/i915/display/intel_hdcp.c | 13 ++++++++++++-
>> 2 files changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
>> index 630a94892b7b..401a9a7689fb 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>> @@ -345,6 +345,12 @@ struct intel_hdcp {
>> struct delayed_work check_work;
>> struct work_struct prop_work;
>>
>> + /*
>> + * Flag to differentiate that HDCP is being disabled originated from
>> + * userspace or triggered from kernel DDI disable sequence.
>> + */
>> + bool is_hdcp_undesired;
> Jani and Daniel,
>
> This flag is added as we need to know the origin of the HDCP disable
> (userspace or kernel modeset/DPMS off) at DDI disable sequence. We
> couldn't do that as new_conn state is not available there to retrieve
> the corresponding content protection state.
>
> Hence we do that at atomic check itself and pass the info through this flag,
> which will be referred at hdcp_disable.
>
> If you think we could do it better please suggest the preferred
> alternate method. Else I request your ack for merging this.
I don't know hdcp code all that well, but it seems to me at the root of
the problem is the duplication of the content protection state
(drm_connector_state->content_protection) into the connector
(intel_hdcp->value), and them going out of sync.
If you relied on the connector state alone, you wouldn't have to worry
about changing the intel_hdcp->value member at disable or anywhere;
disable looks at old state and disables based on that. No history/future
information needed. Isn't that roughly what everything else does, why is
hdcp special?
BR,
Jani.
>
> Thanks,
> -Ram
>> +
>> /* HDCP1.4 Encryption status */
>> bool hdcp_encrypted;
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
>> index 0fdbd39f6641..7f631ebd8395 100644
>> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
>> @@ -2002,11 +2002,18 @@ int intel_hdcp_disable(struct intel_connector *connector)
>> mutex_lock(&hdcp->mutex);
>>
>> if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
>> - hdcp->value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
>> if (hdcp->hdcp2_encrypted)
>> ret = _intel_hdcp2_disable(connector);
>> else if (hdcp->hdcp_encrypted)
>> ret = _intel_hdcp_disable(connector);
>> +
>> + if (hdcp->is_hdcp_undesired) {
>> + hdcp->value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
>> + hdcp->is_hdcp_undesired = false;
>> + } else {
>> + hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
>> + schedule_work(&hdcp->prop_work);
>> + }
>> }
>>
>> mutex_unlock(&hdcp->mutex);
>> @@ -2044,6 +2051,7 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
>> {
>> u64 old_cp = old_state->content_protection;
>> u64 new_cp = new_state->content_protection;
>> + struct intel_connector *intel_conn = to_intel_connector(connector);
>> struct drm_crtc_state *crtc_state;
>>
>> if (!new_state->crtc) {
>> @@ -2069,6 +2077,9 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
>> return;
>> }
>>
>> + if (new_cp == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
>> + intel_conn->hdcp.is_hdcp_undesired = true;
>> +
>> crtc_state = drm_atomic_get_new_crtc_state(new_state->state,
>> new_state->crtc);
>> crtc_state->mode_changed = true;
>> --
>> 2.24.0
>>
--
Jani Nikula, Intel Open Source Graphics Center
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