Re: [PATCH v6 13/26] drm/encoder: add drm_encoder_cleanup_from()

Luca Ceresoli
2025-02-07T08:58:14Z

On Fri, 7 Feb 2025 05:03:13 +0200
Dmitry Baryshkov <dmitry.baryshkov@linaro.org> wrote:

> On Thu, Feb 06, 2025 at 07:14:28PM +0100, Luca Ceresoli wrote:
> > Supporting hardware whose final part of the DRM pipeline can be physically
> > removed requires the ability to detach all bridges from a given point to
> > the end of the pipeline.
> >
> > Introduce a variant of drm_encoder_cleanup() for this.
> >
> > Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> >
> > ---
> >
> > Changes in v6: none
> > Changes in v5: none
> > Changes in v4: none
> > Changes in v3: none
> >
> > Changed in v2:
> > - fix a typo in a comment
> > ---
> > drivers/gpu/drm/drm_encoder.c | 21 +++++++++++++++++++++
> > include/drm/drm_encoder.h | 1 +
> > 2 files changed, 22 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
> > index 8f2bc6a28482229fd0b030a1958f87753ad7885f..472dfbefe2960924a4e83bec425af8c7ef5f5265 100644
> > --- a/drivers/gpu/drm/drm_encoder.c
> > +++ b/drivers/gpu/drm/drm_encoder.c
> > @@ -207,6 +207,27 @@ void drm_encoder_cleanup(struct drm_encoder *encoder)
> > }
> > EXPORT_SYMBOL(drm_encoder_cleanup);
> >
> > +/**
> > + * drm_encoder_cleanup_from - remove a given bridge and all the following
> > + * @encoder: encoder whole list of bridges shall be pruned
> > + * @bridge: first bridge to remove
> > + *
> > + * Removes from an encoder all the bridges starting with a given bridge
> > + * and until the end of the chain.
> > + *
> > + * This should not be used in "normal" DRM pipelines. It is only useful for
> > + * devices whose final part of the DRM chain can be physically removed and
> > + * later reconnected (possibly with different hardware).
> > + */
> > +void drm_encoder_cleanup_from(struct drm_encoder *encoder, struct drm_bridge *bridge)
> > +{
> > + struct drm_bridge *next;
> > +
> > + list_for_each_entry_safe_from(bridge, next, &encoder->bridge_chain, chain_node)
> > + drm_bridge_detach(bridge);
> > +}
> > +EXPORT_SYMBOL(drm_encoder_cleanup_from);
>
> Shouldn't drm_encoder_cleanup() also use this function?

Sure. I'll do it in v7.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering