[PATCH v2 1/6] drm: Include the encoder itself in possible_clones

[Daniel Vetter]

On Fri, Feb 07, 2020 at 03:59:45PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The docs say possible_clones should always include the encoder itself.
> Since most drivers don't want to deal with the complexities of cloning
> let's allow them to set possible_clones=0 and instead we'll fix that
> up in the core.
> 
> We can't put this special case into drm_encoder_init() because drivers
> will have to fill up possible_clones after adding all the relevant
> encoders. Otherwise they wouldn't know the proper encoder indexes to
> use. So we'll just do it just before registering the encoders.
> 
> TODO: Should we do something similar for possible_crtcs==0?
> 
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/drm_encoder.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
> index e555281f43d4..f761d9306028 100644
> --- a/drivers/gpu/drm/drm_encoder.c
> +++ b/drivers/gpu/drm/drm_encoder.c
> @@ -66,11 +66,26 @@ static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
>  	{ DRM_MODE_ENCODER_DPI, "DPI" },
>  };
>  
> +/*
> + * For some reason we want the encoder itself included in
> + * possible_clones. Make life easy for drivers by allowing them
> + * to leave possible_clones unset if no cloning is possible.
> + */
> +static void fixup_possible_clones(struct drm_device *dev)
> +{
> +	struct drm_encoder *encoder;
> +
> +	drm_for_each_encoder(encoder, dev)
> +		encoder->possible_clones |= drm_encoder_mask(encoder);
> +}
> +
>  int drm_encoder_register_all(struct drm_device *dev)
>  {
>  	struct drm_encoder *encoder;
>  	int ret = 0;
>  
> +	fixup_possible_clones(dev);

This is way too late, we've already registered the chardev minors at this
point. I think we need a new drm_mode_config_validate() at the top of
drm_dev_register, but which does _not_ run when the driver has a ->load
callback (which soon will be no driver at all).

Cheers, Daniel


> +
>  	drm_for_each_encoder(encoder, dev) {
>  		if (encoder->funcs->late_register)
>  			ret = encoder->funcs->late_register(encoder);
> -- 
> 2.24.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch