[PATCH 2/5] drm/bochs: Return an error from connector dpms callback

[Daniel Vetter]

On Wed, Jul 26, 2017 at 10:56:33PM +0200, Takashi Iwai wrote:
> The bochs drm driver doesn't treat with DPMS, so we should return an
> error from the connector dpms callback so that the fbcon can fall back
> to the generic blank mode.
> 
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> ---
>  drivers/gpu/drm/bochs/bochs_kms.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bochs/bochs_kms.c b/drivers/gpu/drm/bochs/bochs_kms.c
> index 6a91e62da2f4..a60d1a05950f 100644
> --- a/drivers/gpu/drm/bochs/bochs_kms.c
> +++ b/drivers/gpu/drm/bochs/bochs_kms.c
> @@ -217,6 +217,13 @@ bochs_connector_best_encoder(struct drm_connector *connector)
>  	return NULL;
>  }
>  
> +static int bochs_connector_dpms(struct drm_connector *connector, int mode)
> +{
> +	drm_helper_connector_dpms(connector, mode);
> +	/* FIXME: return error to make fbcon generic blank working */
> +	return -EINVAL;

Thought about this some more, disabling the screen and return -EINVAL (to
userspace even) feels like rather bad semantics. Could we just do an
-EINVAL instead?

I thought the DPMS off change doesn't do anything anyway, so this is pure
dead code.
-Daniel

> +}
> +
>  static const struct drm_connector_helper_funcs bochs_connector_connector_helper_funcs = {
>  	.get_modes = bochs_connector_get_modes,
>  	.mode_valid = bochs_connector_mode_valid,
> @@ -224,7 +231,7 @@ static const struct drm_connector_helper_funcs bochs_connector_connector_helper_
>  };
>  
>  static const struct drm_connector_funcs bochs_connector_connector_funcs = {
> -	.dpms = drm_helper_connector_dpms,
> +	.dpms = bochs_connector_dpms,
>  	.fill_modes = drm_helper_probe_single_connector_modes,
>  	.destroy = drm_connector_cleanup,
>  };
> -- 
> 2.13.3
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch