From: Sean Paul <sean@poorly.run>
To: Anshuman Gupta <anshuman.gupta@intel.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Sean Paul <seanpaul@chromium.org>,
dri-devel <dri-devel@lists.freedesktop.org>
Subject: Re: [Intel-gfx] [PATCH] drm/i915/hdcp: Avoid duplicate HDCP enables
Date: Thu, 21 May 2020 09:38:15 -0400 [thread overview]
Message-ID: <CAMavQKJRQn4TB5j99dyby38OZzGd8UQSKPDXzd14qDSmjLJLAA@mail.gmail.com> (raw)
In-Reply-To: <20200521092715.GD31478@intel.com>
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
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next prev parent reply other threads:[~2020-05-21 13:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 19:47 [Intel-gfx] [PATCH] drm/i915/hdcp: Avoid duplicate HDCP enables Sean Paul
2020-05-20 20:23 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2020-05-21 4:57 ` [Intel-gfx] [PATCH] " Ramalingam C
2020-05-21 9:27 ` Anshuman Gupta
2020-05-21 13:38 ` Sean Paul [this message]
2020-05-21 5:21 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/hdcp: Avoid duplicate HDCP enables (rev2) Patchwork
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