Re: [PATCH v2] Documentation: gpu: Mention the requirements for new properties
Hi Maxime, On Tue, May 25, 2021 at 12:39:40PM +0200, Maxime Ripard wrote: > On Mon, May 24, 2021 at 07:04:43AM +0300, Laurent Pinchart wrote: > > On Thu, May 20, 2021 at 04:24:35PM +0200, Maxime Ripard wrote: > > > New KMS properties come with a bunch of requirements to avoid each > > > driver from running their own, inconsistent, set of properties, > > > eventually leading to issues like property conflicts, inconsistencies > > > between drivers and semantics, etc. > > > > > > Let's document what we expect. > > > > > > Cc: Alexandre Belloni > > > Cc: Alexandre Torgue > > > Cc: Alex Deucher > > > Cc: Alison Wang > > > Cc: Alyssa Rosenzweig > > > Cc: Andrew Jeffery > > > Cc: Andrzej Hajda > > > Cc: Anitha Chrisanthus > > > Cc: Benjamin Gaignard > > > Cc: Ben Skeggs > > > Cc: Boris Brezillon > > > Cc: Brian Starkey > > > Cc: Chen Feng > > > Cc: Chen-Yu Tsai > > > Cc: Christian Gmeiner > > > Cc: "Christian König" > > > Cc: Chun-Kuang Hu > > > Cc: Edmund Dea > > > Cc: Eric Anholt > > > Cc: Fabio Estevam > > > Cc: Gerd Hoffmann > > > Cc: Haneen Mohammed > > > Cc: Hans de Goede > > > Cc: "Heiko Stübner" > > > Cc: Huang Rui > > > Cc: Hyun Kwon > > > Cc: Inki Dae > > > Cc: Jani Nikula > > > Cc: Jernej Skrabec > > > Cc: Jerome Brunet > > > Cc: Joel Stanley > > > Cc: John Stultz > > > Cc: Jonas Karlman > > > Cc: Jonathan Hunter > > > Cc: Joonas Lahtinen > > > Cc: Joonyoung Shim > > > Cc: Jyri Sarha > > > Cc: Kevin Hilman > > > Cc: Kieran Bingham > > > Cc: Krzysztof Kozlowski > > > Cc: Kyungmin Park > > > Cc: Laurent Pinchart > > > Cc: Linus Walleij > > > Cc: Liviu Dudau > > > Cc: Lucas Stach > > > Cc: Ludovic Desroches > > > Cc: Marek Vasut > > > Cc: Martin Blumenstingl > > > Cc: Matthias Brugger > > > Cc: Maxime Coquelin > > > Cc: Maxime Ripard > > > Cc: Melissa Wen > > > Cc: Neil Armstrong > > > Cc: Nicolas Ferre > > > Cc: "Noralf Trønnes" > > > Cc: NXP Linux Team > > > Cc: Oleksandr Andrushchenko > > > Cc: Patrik Jakobsson > > > Cc: Paul Cercueil > > > Cc: Pengutronix Kernel Team > > > Cc: Philippe Cornu > > > Cc: Philipp Zabel > > > Cc: Qiang Yu > > > Cc: Rob Clark > > > Cc: Robert Foss > > > Cc: Rob Herring > > > Cc: Rodrigo Siqueira > > > Cc: Rodrigo Vivi > > > Cc: Roland Scheidegger > > > Cc: Russell King > > > Cc: Sam Ravnborg > > > Cc: Sandy Huang > > > Cc: Sascha Hauer > > > Cc: Sean Paul > > > Cc: Seung-Woo Kim > > > Cc: Shawn Guo > > > Cc: Stefan Agner > > > Cc: Steven Price > > > Cc: Sumit Semwal > > > Cc: Thierry Reding > > > Cc: Tian Tao > > > Cc: Tomeu Vizoso > > > Cc: Tomi Valkeinen > > > Cc: VMware Graphics > > > Cc: Xinliang Liu > > > Cc: Xinwei Kong > > > Cc: Yannick Fertre > > > Cc: Zack Rusin > > > Reviewed-by: Daniel Vetter > > > Signed-off-by: Maxime Ripard > > > > > > --- > > > > > > Changes from v2: > > > - Typos and wording reported by Daniel and Alex > > > --- > > > Documentation/gpu/drm-kms.rst | 19 +++ > > > 1 file changed, 19 insertions(+) > > > > > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > > > index 87e5023e3f55..c28b464dd397 100644 > > > --- a/Documentation/gpu/drm-kms.rst > > > +++ b/Documentation/gpu/drm-kms.rst > > > @@ -463,6 +463,25 @@ KMS Properties > > > This section of the documentation is primarily aimed at user-space > > > developers. > > > For the driver APIs, see the other sections. > > > > > > +Requirements > > > + > > > + > > > +KMS drivers might need to add extra properties to support new features. > > > +Each new property introduced in a driver need to meet a few > > > > s/need/needs/ > > > > > +requirements, in addition to the one mentioned above.: > > > > s/above./above/ > > > > > + > > > +- It must be standardized, with some documentation to describe how the > > > + property can be used. > > > + > > > +- It must provide a generic helper in the core code to register that > > > + property on the object it attaches to. > > > + > > > +- Its content must be decoded by the core and provided in the object's > > > + associated state structure. That includes anything drivers might want > > > to > > > + precompute, like :c:type:`struct drm_clip_rect ` for > > > planes. > > > > Does this effectively mean that we completely forbid driver-specific > > properties ? While I agree that we should strive for standardization, > > there are two issues that worry me. The first one is simple, we may need > > to control features that would be very device-specific, and > > standardizing properties doesn't seem to make much sense in that case. > > I'd say that we should make it clear in that case that it's > driver-specific. > > > The second issue relates to properties that could be applicable to > > multiple devices, but for which we have a single driver. Designing a > > standard with a single data point usually leads to a bad design. I'm not > > sure how to handle this correctly though, as we certainly don't
Re: [PATCH v2] Documentation: gpu: Mention the requirements for new properties
Hi Maxime, On Tue, May 25, 2021 at 12:39:40PM +0200, Maxime Ripard wrote: > > Hi Laurent, > > On Mon, May 24, 2021 at 07:04:43AM +0300, Laurent Pinchart wrote: > > Hi Maxime, > > > > Thank you for the patch. > > > > On Thu, May 20, 2021 at 04:24:35PM +0200, Maxime Ripard wrote: > > > New KMS properties come with a bunch of requirements to avoid each > > > driver from running their own, inconsistent, set of properties, > > > eventually leading to issues like property conflicts, inconsistencies > > > between drivers and semantics, etc. > > > > > > Let's document what we expect. > > > > > > Cc: Alexandre Belloni > > > Cc: Alexandre Torgue > > > Cc: Alex Deucher > > > Cc: Alison Wang > > > Cc: Alyssa Rosenzweig > > > Cc: Andrew Jeffery > > > Cc: Andrzej Hajda > > > Cc: Anitha Chrisanthus > > > Cc: Benjamin Gaignard > > > Cc: Ben Skeggs > > > Cc: Boris Brezillon > > > Cc: Brian Starkey > > > Cc: Chen Feng > > > Cc: Chen-Yu Tsai > > > Cc: Christian Gmeiner > > > Cc: "Christian König" > > > Cc: Chun-Kuang Hu > > > Cc: Edmund Dea > > > Cc: Eric Anholt > > > Cc: Fabio Estevam > > > Cc: Gerd Hoffmann > > > Cc: Haneen Mohammed > > > Cc: Hans de Goede > > > Cc: "Heiko Stübner" > > > Cc: Huang Rui > > > Cc: Hyun Kwon > > > Cc: Inki Dae > > > Cc: Jani Nikula > > > Cc: Jernej Skrabec > > > Cc: Jerome Brunet > > > Cc: Joel Stanley > > > Cc: John Stultz > > > Cc: Jonas Karlman > > > Cc: Jonathan Hunter > > > Cc: Joonas Lahtinen > > > Cc: Joonyoung Shim > > > Cc: Jyri Sarha > > > Cc: Kevin Hilman > > > Cc: Kieran Bingham > > > Cc: Krzysztof Kozlowski > > > Cc: Kyungmin Park > > > Cc: Laurent Pinchart > > > Cc: Linus Walleij > > > Cc: Liviu Dudau > > > Cc: Lucas Stach > > > Cc: Ludovic Desroches > > > Cc: Marek Vasut > > > Cc: Martin Blumenstingl > > > Cc: Matthias Brugger > > > Cc: Maxime Coquelin > > > Cc: Maxime Ripard > > > Cc: Melissa Wen > > > Cc: Neil Armstrong > > > Cc: Nicolas Ferre > > > Cc: "Noralf Trønnes" > > > Cc: NXP Linux Team > > > Cc: Oleksandr Andrushchenko > > > Cc: Patrik Jakobsson > > > Cc: Paul Cercueil > > > Cc: Pengutronix Kernel Team > > > Cc: Philippe Cornu > > > Cc: Philipp Zabel > > > Cc: Qiang Yu > > > Cc: Rob Clark > > > Cc: Robert Foss > > > Cc: Rob Herring > > > Cc: Rodrigo Siqueira > > > Cc: Rodrigo Vivi > > > Cc: Roland Scheidegger > > > Cc: Russell King > > > Cc: Sam Ravnborg > > > Cc: Sandy Huang > > > Cc: Sascha Hauer > > > Cc: Sean Paul > > > Cc: Seung-Woo Kim > > > Cc: Shawn Guo > > > Cc: Stefan Agner > > > Cc: Steven Price > > > Cc: Sumit Semwal > > > Cc: Thierry Reding > > > Cc: Tian Tao > > > Cc: Tomeu Vizoso > > > Cc: Tomi Valkeinen > > > Cc: VMware Graphics > > > Cc: Xinliang Liu > > > Cc: Xinwei Kong > > > Cc: Yannick Fertre > > > Cc: Zack Rusin > > > Reviewed-by: Daniel Vetter > > > Signed-off-by: Maxime Ripard > > > > > > --- > > > > > > Changes from v2: > > > - Typos and wording reported by Daniel and Alex > > > --- > > > Documentation/gpu/drm-kms.rst | 19 +++ > > > 1 file changed, 19 insertions(+) > > > > > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > > > index 87e5023e3f55..c28b464dd397 100644 > > > --- a/Documentation/gpu/drm-kms.rst > > > +++ b/Documentation/gpu/drm-kms.rst > > > @@ -463,6 +463,25 @@ KMS Properties > > > This section of the documentation is primarily aimed at user-space > > > developers. > > > For the driver APIs, see the other sections. > > > > > > +Requirements > > > + > > > + > > > +KMS drivers might need to add extra properties to support new features. > > > +Each new property introduced in a driver need to meet a few > > > > s/need/needs/ > > > > > +requirements, in addition to the one mentioned above.: > > > > s/above./above/ > > > > > + > > > +- It must be standardized, with some documentation to describe how the > > > + property can be used. > > > + > > > +- It must provide a generic helper in the core code to register that > > > + property on the object it attaches to. > > > + > > > +- Its content must be decoded by the core and provided in the object's > > > + associated state structure. That includes anything drivers might want > > > to > > > + precompute, like :c:type:`struct drm_clip_rect ` for > > > planes. > > > > Does this effectively mean that we completely forbid driver-specific > > properties ? While I agree that we should strive for standardization, > > there are two issues that worry me. The first one is simple, we may need > > to control features that would be very device-specific, and > > standardizing properties doesn't seem to make much sense in that case. > > I'd say that we should make it clear in that case that it's > driver-specific. > > > The second issue relates to properties that could be applicable to > > multiple devices, but for which we have a single driver. Designing a > > standard with a single data point usually leads to a bad design.
Re: [PATCH v2] Documentation: gpu: Mention the requirements for new properties
Hi Laurent, On Mon, May 24, 2021 at 07:04:43AM +0300, Laurent Pinchart wrote: > Hi Maxime, > > Thank you for the patch. > > On Thu, May 20, 2021 at 04:24:35PM +0200, Maxime Ripard wrote: > > New KMS properties come with a bunch of requirements to avoid each > > driver from running their own, inconsistent, set of properties, > > eventually leading to issues like property conflicts, inconsistencies > > between drivers and semantics, etc. > > > > Let's document what we expect. > > > > Cc: Alexandre Belloni > > Cc: Alexandre Torgue > > Cc: Alex Deucher > > Cc: Alison Wang > > Cc: Alyssa Rosenzweig > > Cc: Andrew Jeffery > > Cc: Andrzej Hajda > > Cc: Anitha Chrisanthus > > Cc: Benjamin Gaignard > > Cc: Ben Skeggs > > Cc: Boris Brezillon > > Cc: Brian Starkey > > Cc: Chen Feng > > Cc: Chen-Yu Tsai > > Cc: Christian Gmeiner > > Cc: "Christian König" > > Cc: Chun-Kuang Hu > > Cc: Edmund Dea > > Cc: Eric Anholt > > Cc: Fabio Estevam > > Cc: Gerd Hoffmann > > Cc: Haneen Mohammed > > Cc: Hans de Goede > > Cc: "Heiko Stübner" > > Cc: Huang Rui > > Cc: Hyun Kwon > > Cc: Inki Dae > > Cc: Jani Nikula > > Cc: Jernej Skrabec > > Cc: Jerome Brunet > > Cc: Joel Stanley > > Cc: John Stultz > > Cc: Jonas Karlman > > Cc: Jonathan Hunter > > Cc: Joonas Lahtinen > > Cc: Joonyoung Shim > > Cc: Jyri Sarha > > Cc: Kevin Hilman > > Cc: Kieran Bingham > > Cc: Krzysztof Kozlowski > > Cc: Kyungmin Park > > Cc: Laurent Pinchart > > Cc: Linus Walleij > > Cc: Liviu Dudau > > Cc: Lucas Stach > > Cc: Ludovic Desroches > > Cc: Marek Vasut > > Cc: Martin Blumenstingl > > Cc: Matthias Brugger > > Cc: Maxime Coquelin > > Cc: Maxime Ripard > > Cc: Melissa Wen > > Cc: Neil Armstrong > > Cc: Nicolas Ferre > > Cc: "Noralf Trønnes" > > Cc: NXP Linux Team > > Cc: Oleksandr Andrushchenko > > Cc: Patrik Jakobsson > > Cc: Paul Cercueil > > Cc: Pengutronix Kernel Team > > Cc: Philippe Cornu > > Cc: Philipp Zabel > > Cc: Qiang Yu > > Cc: Rob Clark > > Cc: Robert Foss > > Cc: Rob Herring > > Cc: Rodrigo Siqueira > > Cc: Rodrigo Vivi > > Cc: Roland Scheidegger > > Cc: Russell King > > Cc: Sam Ravnborg > > Cc: Sandy Huang > > Cc: Sascha Hauer > > Cc: Sean Paul > > Cc: Seung-Woo Kim > > Cc: Shawn Guo > > Cc: Stefan Agner > > Cc: Steven Price > > Cc: Sumit Semwal > > Cc: Thierry Reding > > Cc: Tian Tao > > Cc: Tomeu Vizoso > > Cc: Tomi Valkeinen > > Cc: VMware Graphics > > Cc: Xinliang Liu > > Cc: Xinwei Kong > > Cc: Yannick Fertre > > Cc: Zack Rusin > > Reviewed-by: Daniel Vetter > > Signed-off-by: Maxime Ripard > > > > --- > > > > Changes from v2: > > - Typos and wording reported by Daniel and Alex > > --- > > Documentation/gpu/drm-kms.rst | 19 +++ > > 1 file changed, 19 insertions(+) > > > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > > index 87e5023e3f55..c28b464dd397 100644 > > --- a/Documentation/gpu/drm-kms.rst > > +++ b/Documentation/gpu/drm-kms.rst > > @@ -463,6 +463,25 @@ KMS Properties > > This section of the documentation is primarily aimed at user-space > > developers. > > For the driver APIs, see the other sections. > > > > +Requirements > > + > > + > > +KMS drivers might need to add extra properties to support new features. > > +Each new property introduced in a driver need to meet a few > > s/need/needs/ > > > +requirements, in addition to the one mentioned above.: > > s/above./above/ > > > + > > +- It must be standardized, with some documentation to describe how the > > + property can be used. > > + > > +- It must provide a generic helper in the core code to register that > > + property on the object it attaches to. > > + > > +- Its content must be decoded by the core and provided in the object's > > + associated state structure. That includes anything drivers might want to > > + precompute, like :c:type:`struct drm_clip_rect ` for > > planes. > > Does this effectively mean that we completely forbid driver-specific > properties ? While I agree that we should strive for standardization, > there are two issues that worry me. The first one is simple, we may need > to control features that would be very device-specific, and > standardizing properties doesn't seem to make much sense in that case. I'd say that we should make it clear in that case that it's driver-specific. > The second issue relates to properties that could be applicable to > multiple devices, but for which we have a single driver. Designing a > standard with a single data point usually leads to a bad design. I'm not > sure how to handle this correctly though, as we certainly don't want > this to be taken as an excuse to create driver-specific properties when > generic properties would make sense. The discussion that made us create that patch was about this property: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/sti/sti_hdmi.c#n170 It's all kind of bad: - It
Re: [PATCH v2] Documentation: gpu: Mention the requirements for new properties
Hi Maxime, Thank you for the patch. On Thu, May 20, 2021 at 04:24:35PM +0200, Maxime Ripard wrote: > New KMS properties come with a bunch of requirements to avoid each > driver from running their own, inconsistent, set of properties, > eventually leading to issues like property conflicts, inconsistencies > between drivers and semantics, etc. > > Let's document what we expect. > > Cc: Alexandre Belloni > Cc: Alexandre Torgue > Cc: Alex Deucher > Cc: Alison Wang > Cc: Alyssa Rosenzweig > Cc: Andrew Jeffery > Cc: Andrzej Hajda > Cc: Anitha Chrisanthus > Cc: Benjamin Gaignard > Cc: Ben Skeggs > Cc: Boris Brezillon > Cc: Brian Starkey > Cc: Chen Feng > Cc: Chen-Yu Tsai > Cc: Christian Gmeiner > Cc: "Christian König" > Cc: Chun-Kuang Hu > Cc: Edmund Dea > Cc: Eric Anholt > Cc: Fabio Estevam > Cc: Gerd Hoffmann > Cc: Haneen Mohammed > Cc: Hans de Goede > Cc: "Heiko Stübner" > Cc: Huang Rui > Cc: Hyun Kwon > Cc: Inki Dae > Cc: Jani Nikula > Cc: Jernej Skrabec > Cc: Jerome Brunet > Cc: Joel Stanley > Cc: John Stultz > Cc: Jonas Karlman > Cc: Jonathan Hunter > Cc: Joonas Lahtinen > Cc: Joonyoung Shim > Cc: Jyri Sarha > Cc: Kevin Hilman > Cc: Kieran Bingham > Cc: Krzysztof Kozlowski > Cc: Kyungmin Park > Cc: Laurent Pinchart > Cc: Linus Walleij > Cc: Liviu Dudau > Cc: Lucas Stach > Cc: Ludovic Desroches > Cc: Marek Vasut > Cc: Martin Blumenstingl > Cc: Matthias Brugger > Cc: Maxime Coquelin > Cc: Maxime Ripard > Cc: Melissa Wen > Cc: Neil Armstrong > Cc: Nicolas Ferre > Cc: "Noralf Trønnes" > Cc: NXP Linux Team > Cc: Oleksandr Andrushchenko > Cc: Patrik Jakobsson > Cc: Paul Cercueil > Cc: Pengutronix Kernel Team > Cc: Philippe Cornu > Cc: Philipp Zabel > Cc: Qiang Yu > Cc: Rob Clark > Cc: Robert Foss > Cc: Rob Herring > Cc: Rodrigo Siqueira > Cc: Rodrigo Vivi > Cc: Roland Scheidegger > Cc: Russell King > Cc: Sam Ravnborg > Cc: Sandy Huang > Cc: Sascha Hauer > Cc: Sean Paul > Cc: Seung-Woo Kim > Cc: Shawn Guo > Cc: Stefan Agner > Cc: Steven Price > Cc: Sumit Semwal > Cc: Thierry Reding > Cc: Tian Tao > Cc: Tomeu Vizoso > Cc: Tomi Valkeinen > Cc: VMware Graphics > Cc: Xinliang Liu > Cc: Xinwei Kong > Cc: Yannick Fertre > Cc: Zack Rusin > Reviewed-by: Daniel Vetter > Signed-off-by: Maxime Ripard > > --- > > Changes from v2: > - Typos and wording reported by Daniel and Alex > --- > Documentation/gpu/drm-kms.rst | 19 +++ > 1 file changed, 19 insertions(+) > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > index 87e5023e3f55..c28b464dd397 100644 > --- a/Documentation/gpu/drm-kms.rst > +++ b/Documentation/gpu/drm-kms.rst > @@ -463,6 +463,25 @@ KMS Properties > This section of the documentation is primarily aimed at user-space > developers. > For the driver APIs, see the other sections. > > +Requirements > + > + > +KMS drivers might need to add extra properties to support new features. > +Each new property introduced in a driver need to meet a few s/need/needs/ > +requirements, in addition to the one mentioned above.: s/above./above/ > + > +- It must be standardized, with some documentation to describe how the > + property can be used. > + > +- It must provide a generic helper in the core code to register that > + property on the object it attaches to. > + > +- Its content must be decoded by the core and provided in the object's > + associated state structure. That includes anything drivers might want to > + precompute, like :c:type:`struct drm_clip_rect ` for planes. Does this effectively mean that we completely forbid driver-specific properties ? While I agree that we should strive for standardization, there are two issues that worry me. The first one is simple, we may need to control features that would be very device-specific, and standardizing properties doesn't seem to make much sense in that case. The second issue relates to properties that could be applicable to multiple devices, but for which we have a single driver. Designing a standard with a single data point usually leads to a bad design. I'm not sure how to handle this correctly though, as we certainly don't want this to be taken as an excuse to create driver-specific properties when generic properties would make sense. > +- An IGT test must be submitted where reasonable. > + > Property Types and Blob Property Support > > -- Regards, Laurent Pinchart
[PATCH v2] Documentation: gpu: Mention the requirements for new properties
New KMS properties come with a bunch of requirements to avoid each driver from running their own, inconsistent, set of properties, eventually leading to issues like property conflicts, inconsistencies between drivers and semantics, etc. Let's document what we expect. Cc: Alexandre Belloni Cc: Alexandre Torgue Cc: Alex Deucher Cc: Alison Wang Cc: Alyssa Rosenzweig Cc: Andrew Jeffery Cc: Andrzej Hajda Cc: Anitha Chrisanthus Cc: Benjamin Gaignard Cc: Ben Skeggs Cc: Boris Brezillon Cc: Brian Starkey Cc: Chen Feng Cc: Chen-Yu Tsai Cc: Christian Gmeiner Cc: "Christian König" Cc: Chun-Kuang Hu Cc: Edmund Dea Cc: Eric Anholt Cc: Fabio Estevam Cc: Gerd Hoffmann Cc: Haneen Mohammed Cc: Hans de Goede Cc: "Heiko Stübner" Cc: Huang Rui Cc: Hyun Kwon Cc: Inki Dae Cc: Jani Nikula Cc: Jernej Skrabec Cc: Jerome Brunet Cc: Joel Stanley Cc: John Stultz Cc: Jonas Karlman Cc: Jonathan Hunter Cc: Joonas Lahtinen Cc: Joonyoung Shim Cc: Jyri Sarha Cc: Kevin Hilman Cc: Kieran Bingham Cc: Krzysztof Kozlowski Cc: Kyungmin Park Cc: Laurent Pinchart Cc: Linus Walleij Cc: Liviu Dudau Cc: Lucas Stach Cc: Ludovic Desroches Cc: Marek Vasut Cc: Martin Blumenstingl Cc: Matthias Brugger Cc: Maxime Coquelin Cc: Maxime Ripard Cc: Melissa Wen Cc: Neil Armstrong Cc: Nicolas Ferre Cc: "Noralf Trønnes" Cc: NXP Linux Team Cc: Oleksandr Andrushchenko Cc: Patrik Jakobsson Cc: Paul Cercueil Cc: Pengutronix Kernel Team Cc: Philippe Cornu Cc: Philipp Zabel Cc: Qiang Yu Cc: Rob Clark Cc: Robert Foss Cc: Rob Herring Cc: Rodrigo Siqueira Cc: Rodrigo Vivi Cc: Roland Scheidegger Cc: Russell King Cc: Sam Ravnborg Cc: Sandy Huang Cc: Sascha Hauer Cc: Sean Paul Cc: Seung-Woo Kim Cc: Shawn Guo Cc: Stefan Agner Cc: Steven Price Cc: Sumit Semwal Cc: Thierry Reding Cc: Tian Tao Cc: Tomeu Vizoso Cc: Tomi Valkeinen Cc: VMware Graphics Cc: Xinliang Liu Cc: Xinwei Kong Cc: Yannick Fertre Cc: Zack Rusin Reviewed-by: Daniel Vetter Signed-off-by: Maxime Ripard --- Changes from v2: - Typos and wording reported by Daniel and Alex --- Documentation/gpu/drm-kms.rst | 19 +++ 1 file changed, 19 insertions(+) diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst index 87e5023e3f55..c28b464dd397 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -463,6 +463,25 @@ KMS Properties This section of the documentation is primarily aimed at user-space developers. For the driver APIs, see the other sections. +Requirements + + +KMS drivers might need to add extra properties to support new features. +Each new property introduced in a driver need to meet a few +requirements, in addition to the one mentioned above.: + +- It must be standardized, with some documentation to describe how the + property can be used. + +- It must provide a generic helper in the core code to register that + property on the object it attaches to. + +- Its content must be decoded by the core and provided in the object's + associated state structure. That includes anything drivers might want to + precompute, like :c:type:`struct drm_clip_rect ` for planes. + +- An IGT test must be submitted where reasonable. + Property Types and Blob Property Support -- 2.31.1
