On 2020-05-21 at 10:27:21 +0530, Ramalingam C wrote: > On 2020-05-20 at 15:47:44 -0400, Sean Paul wrote: > > From: Sean Paul <seanpaul@xxxxxxxxxxxx> > > > > If userspace sets the CP property to DESIRED while it's already ENABLED, > > the driver will try to re-enable HDCP. On some displays, this will > > result in R0' mismatches. I'm guessing this is because the display is > > still sending back Ri instead of re-authenticating. > > > > At any rate, we can fix this inefficiency easily enough by just nooping > > the DESIRED property set if HDCP is already ENABLED. AFAIU may below patch also solves above issue implicitly. https://patchwork.freedesktop.org/patch/365758/?series=72251&rev=4 Besides that +1 for below Ram comment, it would be better if such type of duplicate enable request should filter by drm_atomic_connector_set_property(). Thanks, Anshuman Gupta. > Sean, > > This will skip the hdcp enable. > > But at present too we will be getting below WARN_ON from intel_hdcp_enable, > to indicate userspace is going wrong with request. > drm_WARN_ON(&dev_priv->drm, > hdcp->value == DRM_MODE_CONTENT_PROTECTION_ENABLED); > > And if we need to filter this out, could we validate the incoming hdcp request at > drm_atomic_connector_set_property() itself? No point in going into the > atomic commit without a valid request. something like > > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c > index a1e5e262bae2..d98b2eeae78d 100644 > --- a/drivers/gpu/drm/drm_atomic_uapi.c > +++ b/drivers/gpu/drm/drm_atomic_uapi.c > @@ -746,6 +746,12 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector, > DRM_DEBUG_KMS("only drivers can set CP Enabled\n"); > return -EINVAL; > } > + if (config->content_protection_property == > + DRM_MODE_CONTENT_PROTECTION_ENABLED && > + val == DRM_MODE_CONTENT_PROTECTION_DESIRED) { > + DRM_DEBUG_KMS("Redundant req for content protection\n"); > + return -EINVAL; > + } > state->content_protection = val; > } else if (property == config->hdcp_content_type_property) { > state->hdcp_content_type = val; > > -Ram > > > > > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx> > > --- > > > > I suspect this is the actual root cause I was chasing with > > "drm/i915/hdcp: Add additional R0' wait". I was able to reproduce the > > R0` messages by marking HDCP desired while it was already enabled. This > > _should_ work, but it seems like some displays handle it more graciously > > than others. > > > > > > drivers/gpu/drm/i915/display/intel_hdcp.c | 10 +++++++--- > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c > > index 2cbc4619b4ce..f770fe0c5595 100644 > > --- a/drivers/gpu/drm/i915/display/intel_hdcp.c > > +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c > > @@ -2156,12 +2156,16 @@ void intel_hdcp_atomic_check(struct drm_connector *connector, > > } > > > > /* > > - * Nothing to do if the state didn't change, or HDCP was activated since > > - * the last commit. And also no change in hdcp content type. > > + * Nothing to do if content type is unchanged and one of: > > + * - state didn't change > > + * - HDCP was activated since the last commit > > + * - attempting to set to desired while already enabled > > */ > > if (old_cp == new_cp || > > (old_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED && > > - new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED)) { > > + new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED) || > > + (old_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED && > > + new_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED)) { > > if (old_state->hdcp_content_type == > > new_state->hdcp_content_type) > > return; > > -- > > Sean Paul, Software Engineer, Google / Chromium OS > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
