On 2020-01-22 at 16:56:06 +0200, Jani Nikula wrote:
> On Wed, 22 Jan 2020, Ramalingam C <ramalingam.c@xxxxxxxxx> wrote:
> > On 2020-01-21 at 14:15:57 +0200, Jani Nikula wrote:
> >> On Tue, 21 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;
> >> >> +
> >> >> /* 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;
> >> > This flag is reset at commit only. What if the atomic check failed?
> >> > Usually atomic check wont fail for HDCP state change. Possible if it is submitted with other request.
> >> > So we need to set true and false both here.
> >>
> >> As I explained in my other mail, you don't have the information
> >> available at this point about possible later atomic check failures. I
> >> think it's wrong to change the connector at check phase. You'd need to
> >> be able to revert the change back to what it was... and that's exactly
> >> the reason why we have old and new states, so we can just throw away the
> >> new state if the check fails.
> > I completely understand that part. And this flag set at atomic_check
> > will not change the connector state, untill hdcp_disable called at
> > atomic commit.
> >
> > I am completely fine if this method is not acceptable. But uAPI documented is
> > already broken (ENABLED "content protection" will remain DESIRED/ENABLED until userspace
> > set it to UNDESIRED). So I am just trying to find a solution to it.
> >
> > Requirement is as follows:
> > ddi_disable()->hdcp_disable() gets called for two scenarios
> > 1. userspace setting the "content protection" to UNDESIRED hence
> > atomic_check will mark it as modeset hence hdcp will be disabled.
> > 2. userspace is not changing the "content protection", but other display
> > operations are leading to the ddi_disable hence hdcp is getting disabled
> >
> > We need to differentiate these two cause for hdcp disable at
> > hdcp_disable so that "content protection" can be set to "DESIRED" from
> > "ENABLED" at second case. else HDCP would have been disabled but
> > property will be left at "ENABLED".
> >
> > In first scenario we dont need to change the "content protection" as the
> > userspace itself set it to "UNDESIRED". kernel just need to disable the
> > authentication.
> >
> > So yes, this broken uAPI needs to be attended, not sure if anyone is
> > affected by this already. Please throw some light on the possible
> > direction from this point.
>
> I still think a large part of your problems are due to duplicating the
> content_protection state to hdcp->value.
>
> You *are* setting new state content_protection to DESIRED at
> intel_hdcp_atomic_check() if it was ENABLED. This should work for both
IMHO we are setting new state to DESRIED if it was ENABLED for disabled connectors.
Earlier i tried similar way in order to fix this issue
if (needs_modeset(new_crtc_state)) /* check this after fastset check has been done in atomic check */
for_each_oldnew_connector_in_state(&state->base, connector, old_conn_state,
new_conn_state, i) {
if (old_conn_state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED
&& new_conn_state->content_protection != DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
new_conn_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
}
but the above solution was missing the uevent part, so i discarded it.
As per uapi doc we still need to send the uevent to notify
if there is change in state from ENABLED -> DESIRED.
drivers/gpu/drm/drm_connector.c +1011 (uapi)
> of your scenarios; I think it's only broken because you lose sync with
> hdcp->value.
I think with above solution fixes broken uapi except uevent part.
I will send a new patch with above solution with FIXME tag for uevent.
Thanks,
Anshuman Gupta.
>
> intel_hdcp_disable() should look at old state and disable if hdcp is
> enabled.
>
> intel_hdcp_enable() should look at new state and enable if hdcp is
> desired.
>
>
> BR,
> Jani.
>
>
>
> >
> > -Ram
> >
> >>
> >> BR,
> >> Jani.
> >>
> >>
> >> >
> >> > -Ram
> >> >> +
> >> >> crtc_state = drm_atomic_get_new_crtc_state(new_state->state,
> >> >> new_state->crtc);
> >> >> crtc_state->mode_changed = true;
> >> >> --
> >> >> 2.24.0
> >> >>
> >> > _______________________________________________
> >> > Intel-gfx mailing list
> >> > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> >> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >>
> >> --
> >> Jani Nikula, Intel Open Source Graphics Center
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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