[PATCH RFC] drm/i2c: tda998x: Only set atomic funcs if bound to atomic drm driver

[Liviu.Dudau at arm.com]

On Fri, Jan 15, 2016 at 02:55:26PM +0200, Jyri Sarha wrote:
> Only set atomic connector callbacks if the tda998x driver is bound to
> a drm driver that supports atomic modesetting. At least
> drm_crtc_helper_set_config() calls connectors dpms callback without
> knowing that it may assume atomic modeset support. Calling
> drm_atomic_helper_connector_dpms() causes a crash with a driver that
> does not have atomic state initialized.

Hi Jyri,

> 
> Fixes commit 9736e988d328 ("drm/i2c: tda998x: Add support for atomic
> modesetting").

First, sorry for the breakage, I did not had any other board to test the
change on.

> 
> Signed-off-by: Jyri Sarha <jsarha at ti.com>
> ---
> I am not sure if this is the best way to fix the issue, but after
> 9736e988d328 Beaglebone-Black HDMI is totally broken and this fixes
> the issue. I am currently working on atomic modesetting for tilcdc,
> but there is no way it makes it to 4.5 release.

Yes, I'm not a big fan of the change either. I would've thought that
you only need to update the .dpms pointer, all other hooks added are
specific to atomic operations (right?). Would it not be simpler to have
a tda998x_connector_dpms() function that calls the appropriate .dpms
function based on the feature check?

Best regards,
Liviu

> 
> Best regards,
> Jyri
> 
>  drivers/gpu/drm/i2c/tda998x_drv.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
> index 012d36d..67d1408 100644
> --- a/drivers/gpu/drm/i2c/tda998x_drv.c
> +++ b/drivers/gpu/drm/i2c/tda998x_drv.c
> @@ -1382,7 +1382,7 @@ static void tda998x_connector_destroy(struct drm_connector *connector)
>  	drm_connector_cleanup(connector);
>  }
>  
> -static const struct drm_connector_funcs tda998x_connector_funcs = {
> +static const struct drm_connector_funcs tda998x_connector_atomic_funcs = {
>  	.dpms = drm_atomic_helper_connector_dpms,
>  	.reset = drm_atomic_helper_connector_reset,
>  	.fill_modes = drm_helper_probe_single_connector_modes,
> @@ -1392,15 +1392,28 @@ static const struct drm_connector_funcs tda998x_connector_funcs = {
>  	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>  };
>  
> +static const struct drm_connector_funcs tda998x_connector_funcs = {
> +	.dpms = drm_helper_connector_dpms,
> +	.fill_modes = drm_helper_probe_single_connector_modes,
> +	.detect = tda998x_connector_detect,
> +	.destroy = tda998x_connector_destroy,
> +};
> +
>  static int tda998x_bind(struct device *dev, struct device *master, void *data)
>  {
>  	struct tda998x_encoder_params *params = dev->platform_data;
>  	struct i2c_client *client = to_i2c_client(dev);
>  	struct drm_device *drm = data;
>  	struct tda998x_priv *priv;
> +	const struct drm_connector_funcs *connector_funcs;
>  	u32 crtcs = 0;
>  	int ret;
>  
> +	if (drm_core_check_feature(drm, DRIVER_ATOMIC))
> +		connector_funcs = &tda998x_connector_atomic_funcs;
> +	else
> +		connector_funcs = &tda998x_connector_funcs;
> +
>  	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>  	if (!priv)
>  		return -ENOMEM;
> @@ -1437,7 +1450,7 @@ static int tda998x_bind(struct device *dev, struct device *master, void *data)
>  	drm_connector_helper_add(&priv->connector,
>  				 &tda998x_connector_helper_funcs);
>  	ret = drm_connector_init(drm, &priv->connector,
> -				 &tda998x_connector_funcs,
> +				 connector_funcs,
>  				 DRM_MODE_CONNECTOR_HDMIA);
>  	if (ret)
>  		goto err_connector;
> -- 
> 1.9.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
====================
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| fix the world,  |
| but they're not |
| giving me the   |
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