[PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[Alexandru Gheorghe]

DRM_MODE_REFLECT_X and DRM_MODE_REFLECT_Y meaning seems a bit unclear
to me, so try to clarify that with a bit of ascii graphics.

Changes since v1:
  - Move the ascii graphics in the kerneldoc where all plane
    properties are already documented and make sure it's properly
    rendered, suggestested by Daniel Vetter.

Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
---
 drivers/gpu/drm/drm_blend.c | 22 ++++++++++++++++++++++
 include/uapi/drm/drm_mode.h |  3 ++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index 402b62d3f072..92f75c5c93ac 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -101,6 +101,28 @@
  *	Without this property the rectangle is only scaled, but not rotated or
  *	reflected.
  *
+ *	Possbile values:
+ *
+ *	"rotate-<degrees>":
+ *		Signals that a drm plane is rotated <degrees> degrees in counter
+ *		clockwise direction.
+ *
+ *	"reflect-<axis>":
+ *		Signals that the contents of a drm plane is reflected along the
+ *		<axis> axis, in the same way as mirroring.
+ *
+ *	reflect-x::
+ *
+ *			|o |    | o|
+ *			|  | -> |  |
+ *			| v|    |v |
+ *
+ * 	reflect-y::
+ *
+ *			|o |    | ^|
+ *			|  | -> |  |
+ *			| v|    |o |
+ *
  * zpos:
  *	Z position is set up with drm_plane_create_zpos_immutable_property() and
  *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 8d67243952f4..d3e0fe31efc5 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -186,8 +186,9 @@ extern "C" {
 /*
  * DRM_MODE_REFLECT_<axis>
  *
- * Signals that the contents of a drm plane is reflected in the <axis> axis,
+ * Signals that the contents of a drm plane is reflected along the <axis> axis,
  * in the same way as mirroring.
+ * See kerneldoc chapter "Plane Composition Properties" for more details.
  *
  * This define is provided as a convenience, looking up the property id
  * using the name->prop id lookup is the preferred method.
-- 
2.18.0

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Re: [PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[Daniel Vetter]

On Mon, Sep 10, 2018 at 06:29:46PM +0100, Alexandru Gheorghe wrote:
> DRM_MODE_REFLECT_X and DRM_MODE_REFLECT_Y meaning seems a bit unclear
> to me, so try to clarify that with a bit of ascii graphics.
> 
> Changes since v1:
>   - Move the ascii graphics in the kerneldoc where all plane
>     properties are already documented and make sure it's properly
>     rendered, suggestested by Daniel Vetter.
> 
> Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
> ---
>  drivers/gpu/drm/drm_blend.c | 22 ++++++++++++++++++++++
>  include/uapi/drm/drm_mode.h |  3 ++-
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> index 402b62d3f072..92f75c5c93ac 100644
> --- a/drivers/gpu/drm/drm_blend.c
> +++ b/drivers/gpu/drm/drm_blend.c
> @@ -101,6 +101,28 @@
>   *	Without this property the rectangle is only scaled, but not rotated or
>   *	reflected.
>   *
> + *	Possbile values:
> + *
> + *	"rotate-<degrees>":
> + *		Signals that a drm plane is rotated <degrees> degrees in counter
> + *		clockwise direction.
> + *
> + *	"reflect-<axis>":
> + *		Signals that the contents of a drm plane is reflected along the
> + *		<axis> axis, in the same way as mirroring.
> + *
> + *	reflect-x::
> + *
> + *			|o |    | o|
> + *			|  | -> |  |
> + *			| v|    |v |
> + *
> + * 	reflect-y::
> + *
> + *			|o |    | ^|
> + *			|  | -> |  |
> + *			| v|    |o |
> + *
>   * zpos:
>   *	Z position is set up with drm_plane_create_zpos_immutable_property() and
>   *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 8d67243952f4..d3e0fe31efc5 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -186,8 +186,9 @@ extern "C" {
>  /*
>   * DRM_MODE_REFLECT_<axis>
>   *
> - * Signals that the contents of a drm plane is reflected in the <axis> axis,
> + * Signals that the contents of a drm plane is reflected along the <axis> axis,
>   * in the same way as mirroring.
> + * See kerneldoc chapter "Plane Composition Properties" for more details.

I think that won't properly hyperlink. Bonus if you fix that (kernel-doc
is just normal sphinx text, plus some additional parsing for backwards
compat). Either way:

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

>   *
>   * This define is provided as a convenience, looking up the property id
>   * using the name->prop id lookup is the preferred method.
> -- 
> 2.18.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[Ville Syrjälä]

On Mon, Sep 10, 2018 at 06:29:46PM +0100, Alexandru Gheorghe wrote:
> DRM_MODE_REFLECT_X and DRM_MODE_REFLECT_Y meaning seems a bit unclear
> to me, so try to clarify that with a bit of ascii graphics.
> 
> Changes since v1:
>   - Move the ascii graphics in the kerneldoc where all plane
>     properties are already documented and make sure it's properly
>     rendered, suggestested by Daniel Vetter.
> 
> Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
> ---
>  drivers/gpu/drm/drm_blend.c | 22 ++++++++++++++++++++++
>  include/uapi/drm/drm_mode.h |  3 ++-
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> index 402b62d3f072..92f75c5c93ac 100644
> --- a/drivers/gpu/drm/drm_blend.c
> +++ b/drivers/gpu/drm/drm_blend.c
> @@ -101,6 +101,28 @@
>   *	Without this property the rectangle is only scaled, but not rotated or
>   *	reflected.
>   *
> + *	Possbile values:
> + *
> + *	"rotate-<degrees>":
> + *		Signals that a drm plane is rotated <degrees> degrees in counter
> + *		clockwise direction.
> + *
> + *	"reflect-<axis>":
> + *		Signals that the contents of a drm plane is reflected along the
> + *		<axis> axis, in the same way as mirroring.

What does "mirroring" mean? Feels like a circular definition here.

Also the relationship between rotate and reflect is missing from these
docs. The order matters, and I do believe we have it specified in some
comment somewhere. Would be good to include it here as well.

> + *
> + *	reflect-x::
> + *
> + *			|o |    | o|
> + *			|  | -> |  |
> + *			| v|    |v |
> + *
> + * 	reflect-y::
> + *
> + *			|o |    | ^|
> + *			|  | -> |  |
> + *			| v|    |o |
> + *
>   * zpos:
>   *	Z position is set up with drm_plane_create_zpos_immutable_property() and
>   *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 8d67243952f4..d3e0fe31efc5 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -186,8 +186,9 @@ extern "C" {
>  /*
>   * DRM_MODE_REFLECT_<axis>
>   *
> - * Signals that the contents of a drm plane is reflected in the <axis> axis,
> + * Signals that the contents of a drm plane is reflected along the <axis> axis,
>   * in the same way as mirroring.
> + * See kerneldoc chapter "Plane Composition Properties" for more details.
>   *
>   * This define is provided as a convenience, looking up the property id
>   * using the name->prop id lookup is the preferred method.
> -- 
> 2.18.0
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Ville Syrjälä
Intel
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Re: [PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[Alexandru-Cosmin Gheorghe]

Hi Ville,

On Tue, Sep 11, 2018 at 03:27:09PM +0300, Ville Syrjälä wrote:
> On Mon, Sep 10, 2018 at 06:29:46PM +0100, Alexandru Gheorghe wrote:
> > DRM_MODE_REFLECT_X and DRM_MODE_REFLECT_Y meaning seems a bit unclear
> > to me, so try to clarify that with a bit of ascii graphics.
> > 
> > Changes since v1:
> >   - Move the ascii graphics in the kerneldoc where all plane
> >     properties are already documented and make sure it's properly
> >     rendered, suggestested by Daniel Vetter.
> > 
> > Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
> > ---
> >  drivers/gpu/drm/drm_blend.c | 22 ++++++++++++++++++++++
> >  include/uapi/drm/drm_mode.h |  3 ++-
> >  2 files changed, 24 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> > index 402b62d3f072..92f75c5c93ac 100644
> > --- a/drivers/gpu/drm/drm_blend.c
> > +++ b/drivers/gpu/drm/drm_blend.c
> > @@ -101,6 +101,28 @@
> >   *	Without this property the rectangle is only scaled, but not rotated or
> >   *	reflected.
> >   *
> > + *	Possbile values:
> > + *
> > + *	"rotate-<degrees>":
> > + *		Signals that a drm plane is rotated <degrees> degrees in counter
> > + *		clockwise direction.
> > + *
> > + *	"reflect-<axis>":
> > + *		Signals that the contents of a drm plane is reflected along the
> > + *		<axis> axis, in the same way as mirroring.
> 
> What does "mirroring" mean? Feels like a circular definition here.
> 

That's why I added the pictures to make it more clear, what
reflect-x/reflect-y means.

> Also the relationship between rotate and reflect is missing from these
> docs. The order matters, and I do believe we have it specified in some
> comment somewhere. Would be good to include it here as well.

That's already explained in the documentation for
drm_plane_create_rotation_property(), which is already referred here.

If you think that stuff should be duplicate here as well, it will have
to be done in another patch, because I already merged this patch in
drm-misc-next.

> 
> > + *
> > + *	reflect-x::
> > + *
> > + *			|o |    | o|
> > + *			|  | -> |  |
> > + *			| v|    |v |
> > + *
> > + * 	reflect-y::
> > + *
> > + *			|o |    | ^|
> > + *			|  | -> |  |
> > + *			| v|    |o |
> > + *
> >   * zpos:
> >   *	Z position is set up with drm_plane_create_zpos_immutable_property() and
> >   *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
> > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> > index 8d67243952f4..d3e0fe31efc5 100644
> > --- a/include/uapi/drm/drm_mode.h
> > +++ b/include/uapi/drm/drm_mode.h
> > @@ -186,8 +186,9 @@ extern "C" {
> >  /*
> >   * DRM_MODE_REFLECT_<axis>
> >   *
> > - * Signals that the contents of a drm plane is reflected in the <axis> axis,
> > + * Signals that the contents of a drm plane is reflected along the <axis> axis,
> >   * in the same way as mirroring.
> > + * See kerneldoc chapter "Plane Composition Properties" for more details.
> >   *
> >   * This define is provided as a convenience, looking up the property id
> >   * using the name->prop id lookup is the preferred method.
> > -- 
> > 2.18.0
> > 
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> -- 
> Ville Syrjälä
> Intel

-- 
Cheers,
Alex G
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Re: [PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[Ville Syrjälä]

On Tue, Sep 11, 2018 at 02:20:22PM +0100, Alexandru-Cosmin Gheorghe wrote:
> Hi Ville,
> 
> On Tue, Sep 11, 2018 at 03:27:09PM +0300, Ville Syrjälä wrote:
> > On Mon, Sep 10, 2018 at 06:29:46PM +0100, Alexandru Gheorghe wrote:
> > > DRM_MODE_REFLECT_X and DRM_MODE_REFLECT_Y meaning seems a bit unclear
> > > to me, so try to clarify that with a bit of ascii graphics.
> > > 
> > > Changes since v1:
> > >   - Move the ascii graphics in the kerneldoc where all plane
> > >     properties are already documented and make sure it's properly
> > >     rendered, suggestested by Daniel Vetter.
> > > 
> > > Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
> > > ---
> > >  drivers/gpu/drm/drm_blend.c | 22 ++++++++++++++++++++++
> > >  include/uapi/drm/drm_mode.h |  3 ++-
> > >  2 files changed, 24 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> > > index 402b62d3f072..92f75c5c93ac 100644
> > > --- a/drivers/gpu/drm/drm_blend.c
> > > +++ b/drivers/gpu/drm/drm_blend.c
> > > @@ -101,6 +101,28 @@
> > >   *	Without this property the rectangle is only scaled, but not rotated or
> > >   *	reflected.
> > >   *
> > > + *	Possbile values:
> > > + *
> > > + *	"rotate-<degrees>":
> > > + *		Signals that a drm plane is rotated <degrees> degrees in counter
> > > + *		clockwise direction.
> > > + *
> > > + *	"reflect-<axis>":
> > > + *		Signals that the contents of a drm plane is reflected along the
> > > + *		<axis> axis, in the same way as mirroring.
> > 
> > What does "mirroring" mean? Feels like a circular definition here.
> > 
> 
> That's why I added the pictures to make it more clear, what
> reflect-x/reflect-y means.

Sure. Doesn't really answer the quesiton I was asking. I propose just
dropping the ", in the same way as mirroring." part. It provides no
useful information that I can see.

> 
> > Also the relationship between rotate and reflect is missing from these
> > docs. The order matters, and I do believe we have it specified in some
> > comment somewhere. Would be good to include it here as well.
> 
> That's already explained in the documentation for
> drm_plane_create_rotation_property(), which is already referred here.
> 
> If you think that stuff should be duplicate here as well, it will have
> to be done in another patch, because I already merged this patch in
> drm-misc-next.

I don't think having multiple different pieces of documentation for the
same thing is a particularly good thing.

> 
> > 
> > > + *
> > > + *	reflect-x::
> > > + *
> > > + *			|o |    | o|
> > > + *			|  | -> |  |
> > > + *			| v|    |v |
> > > + *
> > > + * 	reflect-y::
> > > + *
> > > + *			|o |    | ^|
> > > + *			|  | -> |  |
> > > + *			| v|    |o |
> > > + *
> > >   * zpos:
> > >   *	Z position is set up with drm_plane_create_zpos_immutable_property() and
> > >   *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
> > > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> > > index 8d67243952f4..d3e0fe31efc5 100644
> > > --- a/include/uapi/drm/drm_mode.h
> > > +++ b/include/uapi/drm/drm_mode.h
> > > @@ -186,8 +186,9 @@ extern "C" {
> > >  /*
> > >   * DRM_MODE_REFLECT_<axis>
> > >   *
> > > - * Signals that the contents of a drm plane is reflected in the <axis> axis,
> > > + * Signals that the contents of a drm plane is reflected along the <axis> axis,
> > >   * in the same way as mirroring.
> > > + * See kerneldoc chapter "Plane Composition Properties" for more details.
> > >   *
> > >   * This define is provided as a convenience, looking up the property id
> > >   * using the name->prop id lookup is the preferred method.
> > > -- 
> > > 2.18.0
> > > 
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > 
> > -- 
> > Ville Syrjälä
> > Intel
> 
> -- 
> Cheers,
> Alex G

-- 
Ville Syrjälä
Intel
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Re: [PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[Alexandru-Cosmin Gheorghe]

On Tue, Sep 11, 2018 at 04:45:25PM +0300, Ville Syrjälä wrote:
> On Tue, Sep 11, 2018 at 02:20:22PM +0100, Alexandru-Cosmin Gheorghe wrote:
> > Hi Ville,
> > 
> > On Tue, Sep 11, 2018 at 03:27:09PM +0300, Ville Syrjälä wrote:
> > > On Mon, Sep 10, 2018 at 06:29:46PM +0100, Alexandru Gheorghe wrote:
> > > > DRM_MODE_REFLECT_X and DRM_MODE_REFLECT_Y meaning seems a bit unclear
> > > > to me, so try to clarify that with a bit of ascii graphics.
> > > > 
> > > > Changes since v1:
> > > >   - Move the ascii graphics in the kerneldoc where all plane
> > > >     properties are already documented and make sure it's properly
> > > >     rendered, suggestested by Daniel Vetter.
> > > > 
> > > > Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
> > > > ---
> > > >  drivers/gpu/drm/drm_blend.c | 22 ++++++++++++++++++++++
> > > >  include/uapi/drm/drm_mode.h |  3 ++-
> > > >  2 files changed, 24 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> > > > index 402b62d3f072..92f75c5c93ac 100644
> > > > --- a/drivers/gpu/drm/drm_blend.c
> > > > +++ b/drivers/gpu/drm/drm_blend.c
> > > > @@ -101,6 +101,28 @@
> > > >   *	Without this property the rectangle is only scaled, but not rotated or
> > > >   *	reflected.
> > > >   *
> > > > + *	Possbile values:
> > > > + *
> > > > + *	"rotate-<degrees>":
> > > > + *		Signals that a drm plane is rotated <degrees> degrees in counter
> > > > + *		clockwise direction.
> > > > + *
> > > > + *	"reflect-<axis>":
> > > > + *		Signals that the contents of a drm plane is reflected along the
> > > > + *		<axis> axis, in the same way as mirroring.
> > > 
> > > What does "mirroring" mean? Feels like a circular definition here.
> > > 
> > 
> > That's why I added the pictures to make it more clear, what
> > reflect-x/reflect-y means.
> 
> Sure. Doesn't really answer the quesiton I was asking. I propose just
> dropping the ", in the same way as mirroring." part. It provides no
> useful information that I can see.

I was hopping the picture answers to what exactly mirroring means in
this context, I have nothing against dropping that part from the
description.

> 
> > 
> > > Also the relationship between rotate and reflect is missing from these
> > > docs. The order matters, and I do believe we have it specified in some
> > > comment somewhere. Would be good to include it here as well.
> > 
> > That's already explained in the documentation for
> > drm_plane_create_rotation_property(), which is already referred here.
> > 
> > If you think that stuff should be duplicate here as well, it will have
> > to be done in another patch, because I already merged this patch in
> > drm-misc-next.
> 
> I don't think having multiple different pieces of documentation for the
> same thing is a particularly good thing.

How do you propose to group this information?

> 
> > 
> > > 
> > > > + *
> > > > + *	reflect-x::
> > > > + *
> > > > + *			|o |    | o|
> > > > + *			|  | -> |  |
> > > > + *			| v|    |v |
> > > > + *
> > > > + * 	reflect-y::
> > > > + *
> > > > + *			|o |    | ^|
> > > > + *			|  | -> |  |
> > > > + *			| v|    |o |
> > > > + *
> > > >   * zpos:
> > > >   *	Z position is set up with drm_plane_create_zpos_immutable_property() and
> > > >   *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
> > > > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> > > > index 8d67243952f4..d3e0fe31efc5 100644
> > > > --- a/include/uapi/drm/drm_mode.h
> > > > +++ b/include/uapi/drm/drm_mode.h
> > > > @@ -186,8 +186,9 @@ extern "C" {
> > > >  /*
> > > >   * DRM_MODE_REFLECT_<axis>
> > > >   *
> > > > - * Signals that the contents of a drm plane is reflected in the <axis> axis,
> > > > + * Signals that the contents of a drm plane is reflected along the <axis> axis,
> > > >   * in the same way as mirroring.
> > > > + * See kerneldoc chapter "Plane Composition Properties" for more details.
> > > >   *
> > > >   * This define is provided as a convenience, looking up the property id
> > > >   * using the name->prop id lookup is the preferred method.
> > > > -- 
> > > > 2.18.0
> > > > 
> > > > _______________________________________________
> > > > dri-devel mailing list
> > > > dri-devel@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > > 
> > > -- 
> > > Ville Syrjälä
> > > Intel
> > 
> > -- 
> > Cheers,
> > Alex G
> 
> -- 
> Ville Syrjälä
> Intel

-- 
Cheers,
Alex G
_______________________________________________
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Re: [PATCH v2] drm: Clarify DRM_MODE_REFLECT_X/Y documentation

[Ville Syrjälä]

On Tue, Sep 11, 2018 at 04:48:42PM +0100, Alexandru-Cosmin Gheorghe wrote:
> On Tue, Sep 11, 2018 at 04:45:25PM +0300, Ville Syrjälä wrote:
> > On Tue, Sep 11, 2018 at 02:20:22PM +0100, Alexandru-Cosmin Gheorghe wrote:
> > > Hi Ville,
> > > 
> > > On Tue, Sep 11, 2018 at 03:27:09PM +0300, Ville Syrjälä wrote:
> > > > On Mon, Sep 10, 2018 at 06:29:46PM +0100, Alexandru Gheorghe wrote:
> > > > > DRM_MODE_REFLECT_X and DRM_MODE_REFLECT_Y meaning seems a bit unclear
> > > > > to me, so try to clarify that with a bit of ascii graphics.
> > > > > 
> > > > > Changes since v1:
> > > > >   - Move the ascii graphics in the kerneldoc where all plane
> > > > >     properties are already documented and make sure it's properly
> > > > >     rendered, suggestested by Daniel Vetter.
> > > > > 
> > > > > Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
> > > > > ---
> > > > >  drivers/gpu/drm/drm_blend.c | 22 ++++++++++++++++++++++
> > > > >  include/uapi/drm/drm_mode.h |  3 ++-
> > > > >  2 files changed, 24 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> > > > > index 402b62d3f072..92f75c5c93ac 100644
> > > > > --- a/drivers/gpu/drm/drm_blend.c
> > > > > +++ b/drivers/gpu/drm/drm_blend.c
> > > > > @@ -101,6 +101,28 @@
> > > > >   *	Without this property the rectangle is only scaled, but not rotated or
> > > > >   *	reflected.
> > > > >   *
> > > > > + *	Possbile values:
> > > > > + *
> > > > > + *	"rotate-<degrees>":
> > > > > + *		Signals that a drm plane is rotated <degrees> degrees in counter
> > > > > + *		clockwise direction.
> > > > > + *
> > > > > + *	"reflect-<axis>":
> > > > > + *		Signals that the contents of a drm plane is reflected along the
> > > > > + *		<axis> axis, in the same way as mirroring.
> > > > 
> > > > What does "mirroring" mean? Feels like a circular definition here.
> > > > 
> > > 
> > > That's why I added the pictures to make it more clear, what
> > > reflect-x/reflect-y means.
> > 
> > Sure. Doesn't really answer the quesiton I was asking. I propose just
> > dropping the ", in the same way as mirroring." part. It provides no
> > useful information that I can see.
> 
> I was hopping the picture answers to what exactly mirroring means in
> this context, I have nothing against dropping that part from the
> description.
> 
> > 
> > > 
> > > > Also the relationship between rotate and reflect is missing from these
> > > > docs. The order matters, and I do believe we have it specified in some
> > > > comment somewhere. Would be good to include it here as well.
> > > 
> > > That's already explained in the documentation for
> > > drm_plane_create_rotation_property(), which is already referred here.
> > > 
> > > If you think that stuff should be duplicate here as well, it will have
> > > to be done in another patch, because I already merged this patch in
> > > drm-misc-next.
> > 
> > I don't think having multiple different pieces of documentation for the
> > same thing is a particularly good thing.
> 
> How do you propose to group this information?

I guess just remove the duplicated information from the
drm_plane_create_rotation_property() docs. And maybe add a note there
to tell the reader where the description of the bits can be found?

> 
> > 
> > > 
> > > > 
> > > > > + *
> > > > > + *	reflect-x::
> > > > > + *
> > > > > + *			|o |    | o|
> > > > > + *			|  | -> |  |
> > > > > + *			| v|    |v |
> > > > > + *
> > > > > + * 	reflect-y::
> > > > > + *
> > > > > + *			|o |    | ^|
> > > > > + *			|  | -> |  |
> > > > > + *			| v|    |o |
> > > > > + *
> > > > >   * zpos:
> > > > >   *	Z position is set up with drm_plane_create_zpos_immutable_property() and
> > > > >   *	drm_plane_create_zpos_property(). It controls the visibility of overlapping
> > > > > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> > > > > index 8d67243952f4..d3e0fe31efc5 100644
> > > > > --- a/include/uapi/drm/drm_mode.h
> > > > > +++ b/include/uapi/drm/drm_mode.h
> > > > > @@ -186,8 +186,9 @@ extern "C" {
> > > > >  /*
> > > > >   * DRM_MODE_REFLECT_<axis>
> > > > >   *
> > > > > - * Signals that the contents of a drm plane is reflected in the <axis> axis,
> > > > > + * Signals that the contents of a drm plane is reflected along the <axis> axis,
> > > > >   * in the same way as mirroring.
> > > > > + * See kerneldoc chapter "Plane Composition Properties" for more details.
> > > > >   *
> > > > >   * This define is provided as a convenience, looking up the property id
> > > > >   * using the name->prop id lookup is the preferred method.
> > > > > -- 
> > > > > 2.18.0
> > > > > 
> > > > > _______________________________________________
> > > > > dri-devel mailing list
> > > > > dri-devel@lists.freedesktop.org
> > > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > > > 
> > > > -- 
> > > > Ville Syrjälä
> > > > Intel
> > > 
> > > -- 
> > > Cheers,
> > > Alex G
> > 
> > -- 
> > Ville Syrjälä
> > Intel
> 
> -- 
> Cheers,
> Alex G

-- 
Ville Syrjälä
Intel
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