On Mon, Nov 16, 2015 at 06:19:53PM +0100, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> An encoder is associated with a connector by the DRM core as a result of
> setting up a configuration. Drivers using the atomic or legacy helpers
> should never set up this link, even if it is a static one.
>
> While at it, try to catch this kind of error in the future by adding a
> WARN_ON() in drm_mode_connector_attach_encoder(). Note that this doesn't
> cover all the cases, since drivers could set this up after attaching.
> Drivers that use the atomic helpers will get a warning later on, though,
> so hopefully the two combined cover enough to help people avoid this in
> the future.
>
> Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
> Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Liviu Dudau <Liviu.Dudau@xxxxxxx>
> Cc: Mark yao <mark.yao@xxxxxxxxxxxxxx>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> Daniel, I didn't add your Reviewed-by because I included two more fixes
> for the same errors in the i.MX and shmobile drivers. But I suspect that
> you will want to pick this up into drm/misc anyway.
>
> drivers/gpu/drm/bridge/dw_hdmi.c | 2 --
> drivers/gpu/drm/drm_crtc.c | 14 ++++++++++++++
> drivers/gpu/drm/i2c/tda998x_drv.c | 1 -
> drivers/gpu/drm/imx/parallel-display.c | 2 --
> drivers/gpu/drm/shmobile/shmob_drm_crtc.c | 2 --
> 5 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
> index 56de9f1c95fc..ffef392ccc13 100644
> --- a/drivers/gpu/drm/bridge/dw_hdmi.c
> +++ b/drivers/gpu/drm/bridge/dw_hdmi.c
> @@ -1648,8 +1648,6 @@ static int dw_hdmi_register(struct drm_device *drm, struct dw_hdmi *hdmi)
> drm_connector_init(drm, &hdmi->connector, &dw_hdmi_connector_funcs,
> DRM_MODE_CONNECTOR_HDMIA);
>
> - hdmi->connector.encoder = encoder;
> -
> drm_mode_connector_attach_encoder(&hdmi->connector, encoder);
>
> return 0;
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 24c5434abd1c..bc0693c63ca4 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -4983,6 +4983,20 @@ int drm_mode_connector_attach_encoder(struct drm_connector *connector,
> {
> int i;
>
> + /*
> + * In the past, drivers have attempted to model the static association
> + * of connector to encoder in simple connector/encoder devices using a
> + * direct assignment of connector->encoder = encoder. This connection
> + * is a logical one and the responsibility of the core, so drivers are
> + * expected not to mess with this.
> + *
> + * Note that the error return should've been enough here, but a large
> + * majority of drivers ignores the return value, so add in a big WARN
> + * to get people's attention.
> + */
> + if (WARN_ON(connector->encoder))
> + return -EINVAL;
> +
> for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> if (connector->encoder_ids[i] == 0) {
> connector->encoder_ids[i] = encoder->base.id;
> diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
> index 896b6aaf8c4d..8b0a402190eb 100644
> --- a/drivers/gpu/drm/i2c/tda998x_drv.c
> +++ b/drivers/gpu/drm/i2c/tda998x_drv.c
> @@ -1453,7 +1453,6 @@ static int tda998x_bind(struct device *dev, struct device *master, void *data)
> if (ret)
> goto err_sysfs;
>
> - priv->connector.encoder = &priv->encoder;
> drm_mode_connector_attach_encoder(&priv->connector, &priv->encoder);
For the drivers/gpu/drm/drm_crtc.c and drivers/gpu/drm/i2c/tda998x_drv.c combination, together
with an atomic modesetting enabled KMS driver (HDLCD):
Tested-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
Many thanks,
Liviu
>
> return 0;
> diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c
> index b4deb9cf9d71..57b78226e392 100644
> --- a/drivers/gpu/drm/imx/parallel-display.c
> +++ b/drivers/gpu/drm/imx/parallel-display.c
> @@ -200,8 +200,6 @@ static int imx_pd_register(struct drm_device *drm,
>
> drm_mode_connector_attach_encoder(&imxpd->connector, &imxpd->encoder);
>
> - imxpd->connector.encoder = &imxpd->encoder;
> -
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/shmobile/shmob_drm_crtc.c b/drivers/gpu/drm/shmobile/shmob_drm_crtc.c
> index e9272b0a8592..cb72b35d85d1 100644
> --- a/drivers/gpu/drm/shmobile/shmob_drm_crtc.c
> +++ b/drivers/gpu/drm/shmobile/shmob_drm_crtc.c
> @@ -739,8 +739,6 @@ int shmob_drm_connector_create(struct shmob_drm_device *sdev,
> if (ret < 0)
> goto err_backlight;
>
> - connector->encoder = encoder;
> -
> drm_helper_connector_dpms(connector, DRM_MODE_DPMS_OFF);
> drm_object_property_set_value(&connector->base,
> sdev->ddev->mode_config.dpms_property, DRM_MODE_DPMS_OFF);
> --
> 2.5.0
>
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--
====================
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| but they're not |
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