Re: [PATCH v3] drm/bridge:anx7625: Update HDCP status at atomic_enable()

[Dmitry Baryshkov]

On Fri, Dec 13, 2024 at 10:06:36AM +0000, Xin Ji wrote:
> Hi Dmitry, thanks for the review, I made some changes which change ENABLE to DESIRE
> in .atomic_disable(), I'll upstream it after testing. Thanks!

- Please don't top-post.

- You still didn't explain, why do you want to do this change of HDCP
  status. Could you please provide an explanation before sending the
  next iteration?

> 
> > -----Original Message-----
> > From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > Sent: Thursday, December 12, 2024 5:18 PM
> > To: Xin Ji <xji@xxxxxxxxxxxxxxxx>
> > Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>; Neil Armstrong
> > <neil.armstrong@xxxxxxxxxx>; Robert Foss <rfoss@xxxxxxxxxx>; Laurent Pinchart
> > <Laurent.pinchart@xxxxxxxxxxxxxxxx>; Jonas Karlman <jonas@xxxxxxxxx>;
> > Jernej Skrabec <jernej.skrabec@xxxxxxxxx>; Maarten Lankhorst
> > <maarten.lankhorst@xxxxxxxxxxxxxxx>; Maxime Ripard <mripard@xxxxxxxxxx>;
> > Thomas Zimmermann <tzimmermann@xxxxxxx>; David Airlie
> > <airlied@xxxxxxxxx>; Simona Vetter <simona@xxxxxxxx>; Bernie Liang
> > <bliang@xxxxxxxxxxxxxxxx>; Qilin Wen <qwen@xxxxxxxxxxxxxxxx>;
> > treapking@xxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-
> > kernel@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH v3] drm/bridge:anx7625: Update HDCP status at
> > atomic_enable()
> > 
> > CAUTION: This email originated from outside of the organization. Please do not
> > click links or open attachments unless you recognize the sender, and know the
> > content is safe.
> > 
> > 
> > On Thu, Dec 12, 2024 at 01:51:10PM +0800, Xin Ji wrote:
> > > When user enabled HDCP feature, userspace will set HDCP content to
> > > DRM_MODE_CONTENT_PROTECTION_DESIRED. Next, anx7625 will update
> > HDCP
> > > content to DRM_MODE_CONTENT_PROTECTION_ENABLED if down stream
> > support
> > > HDCP feature.
> > >
> > > However once HDCP content turn to
> > DRM_MODE_CONTENT_PROTECTION_ENABLED
> > > userspace will not update the HDCP content to
> > > DRM_MODE_CONTENT_PROTECTION_UNDESIRED until monitor disconnect.
> > 
> > It seems you've ingored a part of the previous review comment. It's the
> > userspace who triggers the ENABLED -> UNDESIRED transition, not the kernel
> > side. The change to move HDCP handling to atomic_enable() looks fine, the
> > change to disable HDCP is not (unless I misunderstand something).
> > 
> > >
> > > So, anx7625 driver move hdcp content value checking from bridge
> > > interface .atomic_check() to .atomic_enable(), then update hdcp
> > > content according from currently HDCP status. And also disabled HDCP
> > > in bridge interface .atomic_disable().
> > >
> > > Signed-off-by: Xin Ji <xji@xxxxxxxxxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/bridge/analogix/anx7625.c | 74
> > > ++++++++++++++---------
> > >  1 file changed, 46 insertions(+), 28 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > index a2675b121fe4..f96ce5665e8d 100644
> > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > @@ -861,6 +861,22 @@ static int anx7625_hdcp_disable(struct anx7625_data
> > *ctx)
> > >                                TX_HDCP_CTRL0, ~HARD_AUTH_EN & 0xFF);
> > > }
> > >
> > > +static void anx7625_hdcp_disable_and_update_cp(struct anx7625_data
> > > +*ctx) {
> > > +     struct device *dev = ctx->dev;
> > > +
> > > +     if (!ctx->connector)
> > > +             return;
> > > +
> > > +     anx7625_hdcp_disable(ctx);
> > > +
> > > +     ctx->hdcp_cp = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
> > > +     drm_hdcp_update_content_protection(ctx->connector,
> > > +                                        ctx->hdcp_cp);
> > > +
> > > +     dev_dbg(dev, "update CP to UNDESIRE\n"); }
> > > +
> > >  static int anx7625_hdcp_enable(struct anx7625_data *ctx)  {
> > >       u8 bcap;
> > > @@ -2149,34 +2165,6 @@ static int anx7625_connector_atomic_check(struct
> > anx7625_data *ctx,
> > >       if (cp == ctx->hdcp_cp)
> > >               return 0;
> > >
> > > -     if (cp == DRM_MODE_CONTENT_PROTECTION_DESIRED) {
> > > -             if (ctx->dp_en) {
> > > -                     dev_dbg(dev, "enable HDCP\n");
> > > -                     anx7625_hdcp_enable(ctx);
> > > -
> > > -                     queue_delayed_work(ctx->hdcp_workqueue,
> > > -                                        &ctx->hdcp_work,
> > > -                                        msecs_to_jiffies(2000));
> > > -             }
> > > -     }
> > > -
> > > -     if (cp == DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
> > > -             if (ctx->hdcp_cp != DRM_MODE_CONTENT_PROTECTION_ENABLED) {
> > > -                     dev_err(dev, "current CP is not ENABLED\n");
> > > -                     return -EINVAL;
> > > -             }
> > > -             anx7625_hdcp_disable(ctx);
> > > -             ctx->hdcp_cp = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
> > > -             drm_hdcp_update_content_protection(ctx->connector,
> > > -                                                ctx->hdcp_cp);
> > > -             dev_dbg(dev, "update CP to UNDESIRE\n");
> > > -     }
> > > -
> > > -     if (cp == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
> > > -             dev_err(dev, "Userspace illegal set to PROTECTION ENABLE\n");
> > > -             return -EINVAL;
> > > -     }
> > > -
> > >       return 0;
> > >  }
> > >
> > > @@ -2425,6 +2413,8 @@ static void anx7625_bridge_atomic_enable(struct
> > drm_bridge *bridge,
> > >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > >       struct device *dev = ctx->dev;
> > >       struct drm_connector *connector;
> > > +     struct drm_connector_state *conn_state;
> > > +     int cp;
> > >
> > >       dev_dbg(dev, "drm atomic enable\n");
> > >
> > > @@ -2439,6 +2429,32 @@ static void anx7625_bridge_atomic_enable(struct
> > drm_bridge *bridge,
> > >       _anx7625_hpd_polling(ctx, 5000 * 100);
> > >
> > >       anx7625_dp_start(ctx);
> > > +
> > > +     conn_state =
> > > + drm_atomic_get_new_connector_state(state->base.state, connector);
> > > +
> > > +     if (WARN_ON(!conn_state))
> > > +             return;
> > > +
> > > +     cp = conn_state->content_protection;
> > > +     if (cp == DRM_MODE_CONTENT_PROTECTION_DESIRED) {
> > > +             if (ctx->dp_en) {
> > > +                     dev_dbg(dev, "enable HDCP\n");
> > > +                     anx7625_hdcp_enable(ctx);
> > > +
> > > +                     queue_delayed_work(ctx->hdcp_workqueue,
> > > +                                        &ctx->hdcp_work,
> > > +                                        msecs_to_jiffies(2000));
> > > +             }
> > > +     }
> > > +
> > > +     if (cp == DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
> > > +             if (ctx->hdcp_cp != DRM_MODE_CONTENT_PROTECTION_ENABLED) {
> > > +                     dev_err(dev, "current CP is not ENABLED\n");
> > > +                     return;
> > > +             }
> > > +
> > > +             anx7625_hdcp_disable_and_update_cp(ctx);
> > > +     }
> > >  }
> > >
> > >  static void anx7625_bridge_atomic_disable(struct drm_bridge *bridge,
> > > @@ -2449,6 +2465,8 @@ static void anx7625_bridge_atomic_disable(struct
> > > drm_bridge *bridge,
> > >
> > >       dev_dbg(dev, "drm atomic disable\n");
> > >
> > > +     anx7625_hdcp_disable_and_update_cp(ctx);
> > > +
> > >       ctx->connector = NULL;
> > >       anx7625_dp_stop(ctx);
> > >
> > > --
> > > 2.25.1
> > >
> > 
> > --
> > With best wishes
> > Dmitry

-- 
With best wishes
Dmitry