Hi Daniel,
On Thursday 09 July 2015 23:44:28 Daniel Vetter wrote:
> Because of DP MST connectors can now be hotplugged and we must hold
> the right lock when walking the connector lists. Enforce this by
> checking the locking in our shiny new list walking macros.
>
> v2: Extract the locking check into a small static inline helper to
> help readability. This will be more important when we make the
> read list access rules more complicated in later patches. Inspired by
> comments from Chris. Unfortunately, due to header loops around the
> definition of struct drm_device the function interface is a bit funny.
>
> v3: Encoders aren't hotadded/removed. For each dp mst encoder we
> statically create one fake encoder per pipe so that we can support as
> many mst sinks as the hw can (Dave).
>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Dave Airlie <airlied@xxxxxxxxxx>
> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> ---
> include/drm/drm_crtc.h | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 7c95a7df6065..499562274353 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -1589,8 +1589,18 @@ static inline struct drm_property
> *drm_property_find(struct drm_device *dev, #define drm_for_each_crtc(crtc,
> dev) \
> list_for_each_entry(crtc, &(dev)->mode_config.crtc_list, head)
>
> +static inline void
> +assert_drm_connector_list_read_locked(struct drm_mode_config *mode_config)
> +{
> + WARN_ON(!mutex_is_locked(&mode_config->mutex));
I believe this introduced a regression for all drivers that call
drm_mode_config_reset() at .load() time (and there's lots of them), as the
mode config mutex isn't locked then.
> +}
> +
> #define drm_for_each_connector(connector, dev) \
> - list_for_each_entry(connector, &(dev)->mode_config.connector_list, head)
> + for (assert_drm_connector_list_read_locked(&(dev)->mode_config), \
> + connector = list_first_entry(&(dev)->mode_config.connector_list,
\
> + struct drm_connector, head); \
> + &connector->head != (&(dev)->mode_config.connector_list); \
> + connector = list_next_entry(connector, head))
>
> #define drm_for_each_encoder(encoder, dev) \
> list_for_each_entry(encoder, &(dev)->mode_config.encoder_list, head)
--
Regards,
Laurent Pinchart
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