[PATCH] Return only active connectors for GET_RESOURCES

[Chris Wilson]

Quoting Stanislav Lisovskiy (2018-11-28 13:52:10)
> Currently kernel might allocate different connector ids
> for the same outputs in case of DP MST, which seems to
> confuse userspace. There are can be different connector
> ids in the list, which could be assigned to the same
> output, while being in different states.
> This results in issues, like external displays staying
> blank after quick unplugging and plugging back(bug #106250).
> Returning only active DP connectors fixes the issue.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106250
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> ---
>  drivers/gpu/drm/drm_mode_config.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index ee80788f2c40..ec5b2b08a45e 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -143,6 +143,7 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
>         drm_connector_list_iter_begin(dev, &conn_iter);
>         count = 0;
>         connector_id = u64_to_user_ptr(card_res->connector_id_ptr);
> +       DRM_DEBUG_KMS("GetResources: writing connectors start");
>         drm_for_each_connector_iter(connector, &conn_iter) {
>                 /* only expose writeback connectors if userspace understands them */
>                 if (!file_priv->writeback_connectors &&
> @@ -150,15 +151,20 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
>                         continue;

if (READ_ONCE(connector->registration_state) != DRM_CONNECTOR_REGISTERED)
	continue;
>  
>                 if (drm_lease_held(file_priv, connector->base.id)) {