Re: [PATCH v2 1/3] drm/msm/dsi: Support NO_CONNECTOR bridges

[Rob Clark <robdclark@gmail.com>]

On Fri, Oct 1, 2021 at 10:28 AM Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> wrote:
>
> On 21/09/2021 01:57, Rob Clark wrote:
> > From: Rob Clark <robdclark@chromium.org>
> >
> > For now, since we have a mix of bridges which support this flag, which
> > which do *not* support this flag, or work both ways, try it once with
> > NO_CONNECTOR and then fall back to the old way if that doesn't work.
> > Eventually we can drop the fallback path.
> >
> > v2: Add missing drm_connector_attach_encoder() so display actually comes
> >      up when the bridge properly handles the NO_CONNECTOR flag
> >
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>
> I think this patch can go through the drm/msm, while two other patches
> would need to through the drm-misc. Is it correct?

Correct, I made sure things worked in either order (ie. with msm patch
but without bridge patches, and visa versa), so they can land through
different trees

BR,
-R

>
> > ---
> >   drivers/gpu/drm/msm/Kconfig           |  2 ++
> >   drivers/gpu/drm/msm/dsi/dsi_manager.c | 50 ++++++++++++++++++++-------
> >   2 files changed, 39 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
> > index e9c6af78b1d7..36e5ba3ccc28 100644
> > --- a/drivers/gpu/drm/msm/Kconfig
> > +++ b/drivers/gpu/drm/msm/Kconfig
> > @@ -14,6 +14,8 @@ config DRM_MSM
> >       select REGULATOR
> >       select DRM_KMS_HELPER
> >       select DRM_PANEL
> > +     select DRM_BRIDGE
> > +     select DRM_PANEL_BRIDGE
> >       select DRM_SCHED
> >       select SHMEM
> >       select TMPFS
> > diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
> > index c41d39f5b7cf..e25877073d31 100644
> > --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
> > +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
> > @@ -3,6 +3,8 @@
> >    * Copyright (c) 2015, The Linux Foundation. All rights reserved.
> >    */
> >
> > +#include "drm/drm_bridge_connector.h"
> > +
> >   #include "msm_kms.h"
> >   #include "dsi.h"
> >
> > @@ -688,10 +690,10 @@ struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
> >   {
> >       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> >       struct drm_device *dev = msm_dsi->dev;
> > +     struct drm_connector *connector;
> >       struct drm_encoder *encoder;
> >       struct drm_bridge *int_bridge, *ext_bridge;
> > -     struct drm_connector *connector;
> > -     struct list_head *connector_list;
> > +     int ret;
> >
> >       int_bridge = msm_dsi->bridge;
> >       ext_bridge = msm_dsi->external_bridge =
> > @@ -699,22 +701,44 @@ struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
> >
> >       encoder = msm_dsi->encoder;
> >
> > -     /* link the internal dsi bridge to the external bridge */
> > -     drm_bridge_attach(encoder, ext_bridge, int_bridge, 0);
> > -
> >       /*
> > -      * we need the drm_connector created by the external bridge
> > -      * driver (or someone else) to feed it to our driver's
> > -      * priv->connector[] list, mainly for msm_fbdev_init()
> > +      * Try first to create the bridge without it creating its own
> > +      * connector.. currently some bridges support this, and others
> > +      * do not (and some support both modes)
> >        */
> > -     connector_list = &dev->mode_config.connector_list;
> > +     ret = drm_bridge_attach(encoder, ext_bridge, int_bridge,
> > +                     DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > +     if (ret == -EINVAL) {
> > +             struct drm_connector *connector;
> > +             struct list_head *connector_list;
> > +
> > +             /* link the internal dsi bridge to the external bridge */
> > +             drm_bridge_attach(encoder, ext_bridge, int_bridge, 0);
> > +
> > +             /*
> > +              * we need the drm_connector created by the external bridge
> > +              * driver (or someone else) to feed it to our driver's
> > +              * priv->connector[] list, mainly for msm_fbdev_init()
> > +              */
> > +             connector_list = &dev->mode_config.connector_list;
> >
> > -     list_for_each_entry(connector, connector_list, head) {
> > -             if (drm_connector_has_possible_encoder(connector, encoder))
> > -                     return connector;
> > +             list_for_each_entry(connector, connector_list, head) {
> > +                     if (drm_connector_has_possible_encoder(connector, encoder))
> > +                             return connector;
> > +             }
> > +
> > +             return ERR_PTR(-ENODEV);
> > +     }
> > +
> > +     connector = drm_bridge_connector_init(dev, encoder);
> > +     if (IS_ERR(connector)) {
> > +             DRM_ERROR("Unable to create bridge connector\n");
> > +             return ERR_CAST(connector);
> >       }
> >
> > -     return ERR_PTR(-ENODEV);
> > +     drm_connector_attach_encoder(connector, encoder);
> > +
> > +     return connector;
> >   }
> >
> >   void msm_dsi_manager_bridge_destroy(struct drm_bridge *bridge)
> >
>
>
> --
> With best wishes
> Dmitry