linux-kernel - Re: [PATCH] drm/msm: Don't attempt to attach HDMI bridge twice

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Date:   Thu, 19 Mar 2020 11:19:15 -0700
From:   Rob Clark <robdclark@...il.com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        freedreno <freedreno@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/msm: Don't attempt to attach HDMI bridge twice

On Wed, Mar 18, 2020 at 9:39 PM Bjorn Andersson
<bjorn.andersson@...aro.org> wrote:
>
> With the introduction of '3ef2f119bd3e ("drm/msm: Use
> drm_attach_bridge() to attach a bridge to an encoder")' the HDMI bridge
> is attached both in msm_hdmi_bridge_init() and later in
> msm_hdmi_modeset_init().
>
> The second attempt fails as the bridge is already attached to the
> encoder and the whole process is aborted.
>
> So instead make msm_hdmi_bridge_init() just initialize the hdmi_bridge
> object and let msm_hdmi_modeset_init() attach it later.
>
> Fixes: 3ef2f119bd3e ("drm/msm: Use drm_attach_bridge() to attach a bridge to an encoder")
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>

Thanks, I think this should also be solved by:

https://patchwork.freedesktop.org/patch/357331/?series=74611&rev=1

BR,
-R

> ---
>  drivers/gpu/drm/msm/hdmi/hdmi_bridge.c | 19 +++----------------
>  1 file changed, 3 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
> index 6e380db9287b..0e103ee1b730 100644
> --- a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
> +++ b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
> @@ -271,31 +271,18 @@ static const struct drm_bridge_funcs msm_hdmi_bridge_funcs = {
>  /* initialize bridge */
>  struct drm_bridge *msm_hdmi_bridge_init(struct hdmi *hdmi)
>  {
> -       struct drm_bridge *bridge = NULL;
>         struct hdmi_bridge *hdmi_bridge;
> -       int ret;
> +       struct drm_bridge *bridge;
>
>         hdmi_bridge = devm_kzalloc(hdmi->dev->dev,
>                         sizeof(*hdmi_bridge), GFP_KERNEL);
> -       if (!hdmi_bridge) {
> -               ret = -ENOMEM;
> -               goto fail;
> -       }
> +       if (!hdmi_bridge)
> +               return ERR_PTR(-ENOMEM);
>
>         hdmi_bridge->hdmi = hdmi;
>
>         bridge = &hdmi_bridge->base;
>         bridge->funcs = &msm_hdmi_bridge_funcs;
>
> -       ret = drm_bridge_attach(hdmi->encoder, bridge, NULL, 0);
> -       if (ret)
> -               goto fail;
> -
>         return bridge;
> -
> -fail:
> -       if (bridge)
> -               msm_hdmi_bridge_destroy(bridge);
> -
> -       return ERR_PTR(ret);
>  }
> --
> 2.24.0
>