[PATCH 2/2] drm: simple_kms_helper: add support for bridges

[PATCH 2/2] drm: simple_kms_helper: add support for bridges

[Andrea Merello]

Introduce drm_simple_display_pipe_attach_bridge() in order
to make it possible to use drm encoders with the simple display
pipes managed by simple_kms_helpers

Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>

diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
index 3a48c7c..05ee61d 100644
--- a/drivers/gpu/drm/drm_simple_kms_helper.c
+++ b/drivers/gpu/drm/drm_simple_kms_helper.c
@@ -133,6 +133,28 @@ static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
 };

 /**
+ * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
+ * @pipe: simple display pipe object
+ * @bridge: bridge to attach
+ *
+ * Makes it possible to still use the drm_simple_display_pipe helpers when
+ * a DRM bridge has to be used.
+ * Note that you probably want to initialize the pipe by passing a NULL
+ * connector to drm_simple_display_pipe_init()
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
+					struct drm_bridge *bridge)
+{
+	bridge->encoder = &pipe->encoder;
+	pipe->encoder.bridge = bridge;
+	return drm_bridge_attach(pipe->encoder.dev, bridge);
+}
+EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
+
+/**
  * drm_simple_display_pipe_init - Initialize a simple display pipeline
  * @dev: DRM device
  * @pipe: simple display pipe object to initialize
diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index 2690397..1d73bcf 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -85,6 +85,9 @@ struct drm_simple_display_pipe {
 	const struct drm_simple_display_pipe_funcs *funcs;
 };

+int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
+					struct drm_bridge *bridge);
+
 int drm_simple_display_pipe_init(struct drm_device *dev,
 			struct drm_simple_display_pipe *pipe,
 			const struct drm_simple_display_pipe_funcs *funcs,
--
2.7.4
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Re: [PATCH 2/2] drm: simple_kms_helper: add support for bridges

[Daniel Vetter]

On Tue, Aug 23, 2016 at 04:08:04PM +0200, Andrea Merello wrote:
> Introduce drm_simple_display_pipe_attach_bridge() in order
> to make it possible to use drm encoders with the simple display
> pipes managed by simple_kms_helpers
> 
> Suggested-by: Daniel Vetter <daniel@ffwll.ch>
> Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> Cc: Noralf Trønnes <noralf@tronnes.org>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: David Airlie <airlied@linux.ie>

Threading of your patch series is somehow broken, usually that should all
work nicely if you've set up git send-email.

One question: Should we ahve a drm_simple_display_pipe_detach_bridge (for
cleanup) too?
-Daniel

> 
> diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
> index 3a48c7c..05ee61d 100644
> --- a/drivers/gpu/drm/drm_simple_kms_helper.c
> +++ b/drivers/gpu/drm/drm_simple_kms_helper.c
> @@ -133,6 +133,28 @@ static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
>  };
> 
>  /**
> + * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
> + * @pipe: simple display pipe object
> + * @bridge: bridge to attach
> + *
> + * Makes it possible to still use the drm_simple_display_pipe helpers when
> + * a DRM bridge has to be used.
> + * Note that you probably want to initialize the pipe by passing a NULL
> + * connector to drm_simple_display_pipe_init()
> + *
> + * Returns:
> + * Zero on success, negative error code on failure.
> + */
> +int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
> +					struct drm_bridge *bridge)
> +{
> +	bridge->encoder = &pipe->encoder;
> +	pipe->encoder.bridge = bridge;
> +	return drm_bridge_attach(pipe->encoder.dev, bridge);
> +}
> +EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
> +
> +/**
>   * drm_simple_display_pipe_init - Initialize a simple display pipeline
>   * @dev: DRM device
>   * @pipe: simple display pipe object to initialize
> diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
> index 2690397..1d73bcf 100644
> --- a/include/drm/drm_simple_kms_helper.h
> +++ b/include/drm/drm_simple_kms_helper.h
> @@ -85,6 +85,9 @@ struct drm_simple_display_pipe {
>  	const struct drm_simple_display_pipe_funcs *funcs;
>  };
> 
> +int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
> +					struct drm_bridge *bridge);
> +
>  int drm_simple_display_pipe_init(struct drm_device *dev,
>  			struct drm_simple_display_pipe *pipe,
>  			const struct drm_simple_display_pipe_funcs *funcs,
> --
> 2.7.4

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [PATCH 2/2] drm: simple_kms_helper: add support for bridges

[Andrea Merello]

[-- Attachment #1.1: Type: text/plain, Size: 3390 bytes --]

On Tue, Aug 23, 2016 at 5:20 PM, Daniel Vetter <daniel@ffwll.ch> wrote:

> On Tue, Aug 23, 2016 at 04:08:04PM +0200, Andrea Merello wrote:
> > Introduce drm_simple_display_pipe_attach_bridge() in order
> > to make it possible to use drm encoders with the simple display
> > pipes managed by simple_kms_helpers
> >
> > Suggested-by: Daniel Vetter <daniel@ffwll.ch>
> > Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> > Cc: Noralf Trønnes <noralf@tronnes.org>
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: David Airlie <airlied@linux.ie>
>
> Threading of your patch series is somehow broken, usually that should all
> work nicely if you've set up git send-email.
>
> One question: Should we ahve a drm_simple_display_pipe_detach_bridge (for
> cleanup) too?
>

Unsure if it worths. May be nice to have a balanced pair, but it would
probably end up in
a quite redundant one-line func, that only calls drm_bridge_detach with the
very same argument.

..But of course if you want I can add it in v2 series.

(ACK for all other things)

Andrea


> -Daniel
>
> >
> > diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c
> b/drivers/gpu/drm/drm_simple_kms_helper.c
> > index 3a48c7c..05ee61d 100644
> > --- a/drivers/gpu/drm/drm_simple_kms_helper.c
> > +++ b/drivers/gpu/drm/drm_simple_kms_helper.c
> > @@ -133,6 +133,28 @@ static const struct drm_plane_funcs
> drm_simple_kms_plane_funcs = {
> >  };
> >
> >  /**
> > + * drm_simple_display_pipe_attach_bridge - Attach a bridge to the
> display pipe
> > + * @pipe: simple display pipe object
> > + * @bridge: bridge to attach
> > + *
> > + * Makes it possible to still use the drm_simple_display_pipe helpers
> when
> > + * a DRM bridge has to be used.
> > + * Note that you probably want to initialize the pipe by passing a NULL
> > + * connector to drm_simple_display_pipe_init()
> > + *
> > + * Returns:
> > + * Zero on success, negative error code on failure.
> > + */
> > +int drm_simple_display_pipe_attach_bridge(struct
> drm_simple_display_pipe *pipe,
> > +                                     struct drm_bridge *bridge)
> > +{
> > +     bridge->encoder = &pipe->encoder;
> > +     pipe->encoder.bridge = bridge;
> > +     return drm_bridge_attach(pipe->encoder.dev, bridge);
> > +}
> > +EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
> > +
> > +/**
> >   * drm_simple_display_pipe_init - Initialize a simple display pipeline
> >   * @dev: DRM device
> >   * @pipe: simple display pipe object to initialize
> > diff --git a/include/drm/drm_simple_kms_helper.h
> b/include/drm/drm_simple_kms_helper.h
> > index 2690397..1d73bcf 100644
> > --- a/include/drm/drm_simple_kms_helper.h
> > +++ b/include/drm/drm_simple_kms_helper.h
> > @@ -85,6 +85,9 @@ struct drm_simple_display_pipe {
> >       const struct drm_simple_display_pipe_funcs *funcs;
> >  };
> >
> > +int drm_simple_display_pipe_attach_bridge(struct
> drm_simple_display_pipe *pipe,
> > +                                     struct drm_bridge *bridge);
> > +
> >  int drm_simple_display_pipe_init(struct drm_device *dev,
> >                       struct drm_simple_display_pipe *pipe,
> >                       const struct drm_simple_display_pipe_funcs *funcs,
> > --
> > 2.7.4
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
>

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Re: [PATCH 2/2] drm: simple_kms_helper: add support for bridges

[Daniel Vetter]

On Tue, Aug 23, 2016 at 05:39:36PM +0200, Andrea Merello wrote:
> On Tue, Aug 23, 2016 at 5:20 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
> 
> > On Tue, Aug 23, 2016 at 04:08:04PM +0200, Andrea Merello wrote:
> > > Introduce drm_simple_display_pipe_attach_bridge() in order
> > > to make it possible to use drm encoders with the simple display
> > > pipes managed by simple_kms_helpers
> > >
> > > Suggested-by: Daniel Vetter <daniel@ffwll.ch>
> > > Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> > > Cc: Noralf Trønnes <noralf@tronnes.org>
> > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > Cc: David Airlie <airlied@linux.ie>
> >
> > Threading of your patch series is somehow broken, usually that should all
> > work nicely if you've set up git send-email.
> >
> > One question: Should we ahve a drm_simple_display_pipe_detach_bridge (for
> > cleanup) too?
> >
> 
> Unsure if it worths. May be nice to have a balanced pair, but it would
> probably end up in
> a quite redundant one-line func, that only calls drm_bridge_detach with the
> very same argument.
> 
> ..But of course if you want I can add it in v2 series.

Yes it's just going to be a one-line, but it'll do a typecast and so
better encapsulate the internals of the simple pipe helper. I think that's
worth it - we have piles&piles of functions and #defines just to make
little one-line bits of code a notch more readable.

And yes the symmetry is nice too ;-)
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [PATCH 2/2] drm: simple_kms_helper: add support for bridges

[Andrea Merello]

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On Tue, Aug 23, 2016 at 5:54 PM, Daniel Vetter <daniel@ffwll.ch> wrote:

> On Tue, Aug 23, 2016 at 05:39:36PM +0200, Andrea Merello wrote:
> > On Tue, Aug 23, 2016 at 5:20 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
> >
> > > On Tue, Aug 23, 2016 at 04:08:04PM +0200, Andrea Merello wrote:
> > > > Introduce drm_simple_display_pipe_attach_bridge() in order
> > > > to make it possible to use drm encoders with the simple display
> > > > pipes managed by simple_kms_helpers
> > > >
> > > > Suggested-by: Daniel Vetter <daniel@ffwll.ch>
> > > > Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> > > > Cc: Noralf Trønnes <noralf@tronnes.org>
> > > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > > Cc: David Airlie <airlied@linux.ie>
> > >
> > > Threading of your patch series is somehow broken, usually that should
> all
> > > work nicely if you've set up git send-email.
> > >
> > > One question: Should we ahve a drm_simple_display_pipe_detach_bridge
> (for
> > > cleanup) too?
> > >
> >
> > Unsure if it worths. May be nice to have a balanced pair, but it would
> > probably end up in
> > a quite redundant one-line func, that only calls drm_bridge_detach with
> the
> > very same argument.
> >
> > ..But of course if you want I can add it in v2 series.
>
> Yes it's just going to be a one-line, but it'll do a typecast and so
> better encapsulate the internals of the simple pipe helper.


I'm unsure about what do you mean here. Why a typecast?

Wouldn't it be simply drm_simple_display_pipe_detach_bridge(struct
drm_bridge *bridge) calling in turn drm_detach_bridge(struct drm_bridge
*bridge) with the very same argument?

Or if you want to stay behind the pipe, then it could be
drm_simple_display_pipe_detach_bridge(struct drm_simple_display_pipe *pipe),
but I would say it just does something like
drm_bridge_detach(pipe->encoder.bridge), so I don't really get your point
about the cast, sorry..


> I think that's
> worth it - we have piles&piles of functions and #defines just to make
> little one-line bits of code a notch more readable.
>
> And yes the symmetry is nice too ;-)
>

OK, then I'll add it :)

Andrea


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

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Re: [PATCH 2/2] drm: simple_kms_helper: add support for bridges

[Daniel Vetter]

On Tue, Aug 23, 2016 at 06:44:18PM +0200, Andrea Merello wrote:
> On Tue, Aug 23, 2016 at 5:54 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
> 
> > On Tue, Aug 23, 2016 at 05:39:36PM +0200, Andrea Merello wrote:
> > > On Tue, Aug 23, 2016 at 5:20 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
> > >
> > > > On Tue, Aug 23, 2016 at 04:08:04PM +0200, Andrea Merello wrote:
> > > > > Introduce drm_simple_display_pipe_attach_bridge() in order
> > > > > to make it possible to use drm encoders with the simple display
> > > > > pipes managed by simple_kms_helpers
> > > > >
> > > > > Suggested-by: Daniel Vetter <daniel@ffwll.ch>
> > > > > Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> > > > > Cc: Noralf Trønnes <noralf@tronnes.org>
> > > > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > > > Cc: David Airlie <airlied@linux.ie>
> > > >
> > > > Threading of your patch series is somehow broken, usually that should
> > all
> > > > work nicely if you've set up git send-email.
> > > >
> > > > One question: Should we ahve a drm_simple_display_pipe_detach_bridge
> > (for
> > > > cleanup) too?
> > > >
> > >
> > > Unsure if it worths. May be nice to have a balanced pair, but it would
> > > probably end up in
> > > a quite redundant one-line func, that only calls drm_bridge_detach with
> > the
> > > very same argument.
> > >
> > > ..But of course if you want I can add it in v2 series.
> >
> > Yes it's just going to be a one-line, but it'll do a typecast and so
> > better encapsulate the internals of the simple pipe helper.
> 
> 
> I'm unsure about what do you mean here. Why a typecast?
> 
> Wouldn't it be simply drm_simple_display_pipe_detach_bridge(struct
> drm_bridge *bridge) calling in turn drm_detach_bridge(struct drm_bridge
> *bridge) with the very same argument?
> 
> Or if you want to stay behind the pipe, then it could be
> drm_simple_display_pipe_detach_bridge(struct drm_simple_display_pipe *pipe),
> but I would say it just does something like
> drm_bridge_detach(pipe->encoder.bridge), so I don't really get your point
> about the cast, sorry..

Yeah, the latter is what I mean. That way drivers don't have to dig around
in the details of pipe. And it wouldn't be entirely just a wrapper, I
think it'd be good to also clear pipe->encoder.bridge to NULL.

Or do you think this is entirely pointless? Sometimes I do go overboard
with curating pretty little functions ;-)
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [PATCH 2/2] drm: simple_kms_helper: add support for bridges

[Andrea Merello]

[-- Attachment #1.1: Type: text/plain, Size: 2945 bytes --]

On Tue, Aug 23, 2016 at 10:01 PM, Daniel Vetter <daniel@ffwll.ch> wrote:

> On Tue, Aug 23, 2016 at 06:44:18PM +0200, Andrea Merello wrote:
> > On Tue, Aug 23, 2016 at 5:54 PM, Daniel Vetter <daniel@ffwll.ch> wrote:
> >
> > > On Tue, Aug 23, 2016 at 05:39:36PM +0200, Andrea Merello wrote:
> > > > On Tue, Aug 23, 2016 at 5:20 PM, Daniel Vetter <daniel@ffwll.ch>
> wrote:
> > > >
> > > > > On Tue, Aug 23, 2016 at 04:08:04PM +0200, Andrea Merello wrote:
> > > > > > Introduce drm_simple_display_pipe_attach_bridge() in order
> > > > > > to make it possible to use drm encoders with the simple display
> > > > > > pipes managed by simple_kms_helpers
> > > > > >
> > > > > > Suggested-by: Daniel Vetter <daniel@ffwll.ch>
> > > > > > Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> > > > > > Cc: Noralf Trønnes <noralf@tronnes.org>
> > > > > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > > > > Cc: David Airlie <airlied@linux.ie>
> > > > >
> > > > > Threading of your patch series is somehow broken, usually that
> should
> > > all
> > > > > work nicely if you've set up git send-email.
> > > > >
> > > > > One question: Should we ahve a drm_simple_display_pipe_
> detach_bridge
> > > (for
> > > > > cleanup) too?
> > > > >
> > > >
> > > > Unsure if it worths. May be nice to have a balanced pair, but it
> would
> > > > probably end up in
> > > > a quite redundant one-line func, that only calls drm_bridge_detach
> with
> > > the
> > > > very same argument.
> > > >
> > > > ..But of course if you want I can add it in v2 series.
> > >
> > > Yes it's just going to be a one-line, but it'll do a typecast and so
> > > better encapsulate the internals of the simple pipe helper.
> >
> >
> > I'm unsure about what do you mean here. Why a typecast?
> >
> > Wouldn't it be simply drm_simple_display_pipe_detach_bridge(struct
> > drm_bridge *bridge) calling in turn drm_detach_bridge(struct drm_bridge
> > *bridge) with the very same argument?
> >
> > Or if you want to stay behind the pipe, then it could be
> > drm_simple_display_pipe_detach_bridge(struct drm_simple_display_pipe
> *pipe),
> > but I would say it just does something like
> > drm_bridge_detach(pipe->encoder.bridge), so I don't really get your
> point
> > about the cast, sorry..
>
> Yeah, the latter is what I mean. That way drivers don't have to dig around
> in the details of pipe. And it wouldn't be entirely just a wrapper, I
> think it'd be good to also clear pipe->encoder.bridge to NULL.
>
> Yes, since I'm assigning it in drm_simple_display_pipe_attach_bridge, it
seems good to clear it in drm_simple_display_pipe_detach.


> Or do you think this is entirely pointless? Sometimes I do go overboard
> with curating pretty little functions ;-)
>

I guess it shouldn't hurt anyway :)

Andrea

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

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