Quoting Dmitry Baryshkov (2022-02-11 14:40:02)
> In commit 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display
> enable and disable") the DP driver received a drm_bridge instance, which
> is always attached to the encoder as a root bridge. However it conflicts
> with the panel_bridge support for eDP panels. The panel bridge attaches
> to the encoder before the "dp" bridge has a chace to do so. Change
s/chace/chance/
> panel_bridge attachment to come after dp_bridge attachment.
s/panel_bridge/panel bridge/ possibly? And maybe clarify that dp_bridge
is the "DP driver's drm_bridge instance created in
msm_dp_bridge_init()"?
My understanding is that we want to pass the bridge created in
msm_dp_bridge_init() as the 'previous' bridge so that it attaches the
panel bridge to the output of the DP bridge that's attached to the
encoder.
>
> Fixes: 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display enable and disable")
> Cc: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> ---
Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> drivers/gpu/drm/msm/dp/dp_drm.c | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
> index d4d360d19eba..26ef41a4c1b6 100644
> --- a/drivers/gpu/drm/msm/dp/dp_drm.c
> +++ b/drivers/gpu/drm/msm/dp/dp_drm.c
> @@ -169,16 +169,6 @@ struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display)
>
> drm_connector_attach_encoder(connector, dp_display->encoder);
>
> - if (dp_display->panel_bridge) {
> - ret = drm_bridge_attach(dp_display->encoder,
> - dp_display->panel_bridge, NULL,
> - DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> - if (ret < 0) {
> - DRM_ERROR("failed to attach panel bridge: %d\n", ret);
> - return ERR_PTR(ret);
> - }
> - }
> -
> return connector;
> }
>
> @@ -246,5 +236,16 @@ struct drm_bridge *msm_dp_bridge_init(struct msm_dp *dp_display, struct drm_devi
> return ERR_PTR(rc);
> }
>
> + if (dp_display->panel_bridge) {
> + rc = drm_bridge_attach(dp_display->encoder,
> + dp_display->panel_bridge, bridge,
> + DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> + if (rc < 0) {
> + DRM_ERROR("failed to attach panel bridge: %d\n", rc);
> + drm_bridge_remove(bridge);
> + return ERR_PTR(rc);
> + }
> + }
> +
> return bridge;
Not a problem with this patch, but what is this pointer used for? I see
it's assigned to priv->bridges and num_bridges is incremented but nobody
seems to look at that.
