| Message ID | 20200520194744.48936-1-sean@poorly.run (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/hdcp: Avoid duplicate HDCP enables | expand |
On 2020-05-20 at 15:47:44 -0400, Sean Paul wrote: > From: Sean Paul <seanpaul@chromium.org> > > 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. 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@chromium.org> > --- > > 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 >
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@chromium.org> > > > > 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@chromium.org> > > --- > > > > 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 > >
On Thu, May 21, 2020 at 5:36 AM Anshuman Gupta <anshuman.gupta@intel.com> wrote: > > 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@chromium.org> > > > > > > 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, I didn't see that patch. Indeed that seems like it accomplishes the same thing. Let's drop this. Sean > 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@chromium.org> > > > --- > > > > > > 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@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
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;