[PATCH] drm/amdgpu: warn if dp aux is still attached on free

[Alex Deucher]

On Sun, Oct 2, 2016 at 5:06 PM, Grazvydas Ignotas <notasas at gmail.com> wrote:
> If this happens (and it recently did), we free a structure while part of
> it is still in use, which results in non-obvious crashes. The way it's
> detached is not trivial (DRM core has to call the connector .destroy
> callback and things must be torn down in the right order), so better
> detect it and warn early.
>
> Signed-off-by: Grazvydas Ignotas <notasas at gmail.com>

Applied.  thanks!

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 4 +++-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c        | 1 +
>  2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> index ff0b55a..76a7830 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
> @@ -769,8 +769,10 @@ static void amdgpu_connector_destroy(struct drm_connector *connector)
>  {
>         struct amdgpu_connector *amdgpu_connector = to_amdgpu_connector(connector);
>
> -       if (amdgpu_connector->ddc_bus->has_aux)
> +       if (amdgpu_connector->ddc_bus->has_aux) {
>                 drm_dp_aux_unregister(&amdgpu_connector->ddc_bus->aux);
> +               amdgpu_connector->ddc_bus->has_aux = false;
> +       }
>         amdgpu_connector_free_edid(connector);
>         kfree(amdgpu_connector->con_priv);
>         drm_connector_unregister(connector);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> index 34bab61..91d3673 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> @@ -220,6 +220,7 @@ void amdgpu_i2c_destroy(struct amdgpu_i2c_chan *i2c)
>  {
>         if (!i2c)
>                 return;
> +       WARN_ON(i2c->has_aux);
>         i2c_del_adapter(&i2c->adapter);
>         kfree(i2c);
>  }
> --
> 2.7.4
>
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