Messages in this thread | | | Date | Mon, 10 Jul 2023 12:51:53 -0700 | From | Jessica Zhang <> | Subject | Re: [PATCH RFC v4 2/7] drm: Introduce pixel_source DRM plane property |
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On 6/30/2023 1:27 AM, Pekka Paalanen wrote: > On Fri, 30 Jun 2023 03:42:28 +0300 > Dmitry Baryshkov <dmitry.baryshkov@linaro.org> wrote: > >> On 30/06/2023 03:25, Jessica Zhang wrote: >>> Add support for pixel_source property to drm_plane and related >>> documentation. >>> >>> This enum property will allow user to specify a pixel source for the >>> plane. Possible pixel sources will be defined in the >>> drm_plane_pixel_source enum. >>> >>> The current possible pixel sources are DRM_PLANE_PIXEL_SOURCE_FB and >>> DRM_PLANE_PIXEL_SOURCE_COLOR. The default value is *_SOURCE_FB. >> >> I think, this should come before the solid fill property addition. First >> you tell that there is a possibility to define other pixel sources, then >> additional sources are defined. > > Hi, > > that would be logical indeed.
Hi Dmitry and Pekka,
Sorry for the delay in response, was out of office last week.
Acked.
> >>> >>> Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com> >>> --- >>> drivers/gpu/drm/drm_atomic_state_helper.c | 1 + >>> drivers/gpu/drm/drm_atomic_uapi.c | 4 ++ >>> drivers/gpu/drm/drm_blend.c | 81 +++++++++++++++++++++++++++++++ >>> include/drm/drm_blend.h | 2 + >>> include/drm/drm_plane.h | 21 ++++++++ >>> 5 files changed, 109 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c >>> index fe14be2bd2b2..86fb876efbe6 100644 >>> --- a/drivers/gpu/drm/drm_atomic_state_helper.c >>> +++ b/drivers/gpu/drm/drm_atomic_state_helper.c >>> @@ -252,6 +252,7 @@ void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *plane_state, >>> >>> plane_state->alpha = DRM_BLEND_ALPHA_OPAQUE; >>> plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI; >>> + plane_state->pixel_source = DRM_PLANE_PIXEL_SOURCE_FB; >>> >>> if (plane_state->solid_fill_blob) { >>> drm_property_blob_put(plane_state->solid_fill_blob); >>> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c >>> index a28b4ee79444..6e59c21af66b 100644 >>> --- a/drivers/gpu/drm/drm_atomic_uapi.c >>> +++ b/drivers/gpu/drm/drm_atomic_uapi.c >>> @@ -596,6 +596,8 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane, >>> drm_property_blob_put(solid_fill); >>> >>> return ret; >>> + } else if (property == plane->pixel_source_property) { >>> + state->pixel_source = val; >>> } else if (property == plane->alpha_property) { >>> state->alpha = val; >>> } else if (property == plane->blend_mode_property) { >> >> I think, it was pointed out in the discussion that drm_mode_setplane() >> (a pre-atomic IOCTL to turn the plane on and off) should also reset >> pixel_source to FB.
I don't remember drm_mode_setplane() being mentioned in the pixel_source discussion... can you share where it was mentioned?
I'd prefer to avoid having driver change the pixel_source directly as it could cause some unexpected side effects. In general, I would like userspace to assign the value of pixel_source without driver doing anything "under the hood".
>> >>> @@ -671,6 +673,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane, >>> } else if (property == plane->solid_fill_property) { >>> *val = state->solid_fill_blob ? >>> state->solid_fill_blob->base.id : 0; >>> + } else if (property == plane->pixel_source_property) { >>> + *val = state->pixel_source; >>> } else if (property == plane->alpha_property) { >>> *val = state->alpha; >>> } else if (property == plane->blend_mode_property) { >>> diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c >>> index 38c3c5d6453a..8c100a957ee2 100644 >>> --- a/drivers/gpu/drm/drm_blend.c >>> +++ b/drivers/gpu/drm/drm_blend.c >>> @@ -189,6 +189,18 @@ >>> * solid_fill is set up with drm_plane_create_solid_fill_property(). It >>> * contains pixel data that drivers can use to fill a plane. >>> * >>> + * pixel_source: >>> + * pixel_source is set up with drm_plane_create_pixel_source_property(). >>> + * It is used to toggle the source of pixel data for the plane. > > Other sources than the selected one are ignored?
Yep, the plane will only display the data from the set pixel_source.
So if pixel_source == FB and solid_fill_blob is non-NULL, solid_fill_blob will be ignored and the plane will display the FB that is set.
Will add a note about this in the comment docs.
> >>> + * >>> + * Possible values: > > Wouldn't hurt to explicitly mention here that this is an enum.
Acked.
> >>> + * >>> + * "FB": >>> + * Framebuffer source >>> + * >>> + * "COLOR": >>> + * solid_fill source > > I think these two should be more explicit. Framebuffer source is the > usual source from the property "FB_ID". Solid fill source comes from > the property "solid_fill".
Acked.
> > Why "COLOR" and not, say, "SOLID_FILL"?
Ah, that would make more sense :)
I'll change this to "SOLID_FILL".
> >>> + * >>> * Note that all the property extensions described here apply either to the >>> * plane or the CRTC (e.g. for the background color, which currently is not >>> * exposed and assumed to be black). >>> @@ -648,3 +660,72 @@ int drm_plane_create_solid_fill_property(struct drm_plane *plane) >>> return 0; >>> } >>> EXPORT_SYMBOL(drm_plane_create_solid_fill_property); >>> + >>> +/** >>> + * drm_plane_create_pixel_source_property - create a new pixel source property >>> + * @plane: drm plane >>> + * @supported_sources: bitmask of supported pixel_sources for the driver (NOT >>> + * including DRM_PLANE_PIXEL_SOURCE_FB, as it will be supported >>> + * by default). >> >> I'd say this is too strong. I'd suggest either renaming this to >> extra_sources (mentioning that FB is enabled for all the planes) or >> allowing any source bitmask (mentioning that FB should be enabled by the >> caller, unless there is a good reason not to do so). > > Right. I don't see any problem with having planes of type OVERLAY that > support only solid_fill and no FB. Planes of type PRIMARY and CURSOR I > would expect to always support at least FB. > > Atomic userspace is prepared to have an OVERLAY plane fail for any > arbitrary reason. Legacy userspace probably should not ever see a plane > that does not support FB.
Got it... If we allow the possibility of FB sources not being supported, then should the default pixel_source per plane be decided by the driver too?
I'd forced FB support so that I could set pixel_source to FB in __drm_atomic_helper_plane_state_reset(). If we allow more flexibility in the default pixel_source value, I guess we can also store a default_pixel_source value in the plane_state.
> >>> + * >>> + * This creates a new property describing the current source of pixel data for the >>> + * plane. >>> + * >>> + * The property is exposed to userspace as an enumeration property called >>> + * "pixel_source" and has the following enumeration values: >>> + * >>> + * "FB": >>> + * Framebuffer pixel source >>> + * >>> + * "COLOR": >>> + * Solid fill color pixel source >>> + * >>> + * Returns: >>> + * Zero on success, negative errno on failure. >>> + */ >>> +int drm_plane_create_pixel_source_property(struct drm_plane *plane, >>> + unsigned int supported_sources) >>> +{ >>> + struct drm_device *dev = plane->dev; >>> + struct drm_property *prop; >>> + const struct drm_prop_enum_list enum_list[] = { >>> + { DRM_PLANE_PIXEL_SOURCE_FB, "FB" }, >>> + { DRM_PLANE_PIXEL_SOURCE_COLOR, "COLOR" }, >>> + }; >>> + unsigned int valid_source_mask = BIT(DRM_PLANE_PIXEL_SOURCE_FB) | >>> + BIT(DRM_PLANE_PIXEL_SOURCE_COLOR); >> >> >> static const?
Acked.
>> >>> + int i; >>> + >>> + /* FB is supported by default */ >>> + supported_sources |= BIT(DRM_PLANE_PIXEL_SOURCE_FB); >>> + >>> + if (WARN_ON(supported_sources & ~valid_source_mask)) >>> + return -EINVAL; >>> + >>> + prop = drm_property_create(dev, DRM_MODE_PROP_ENUM, "pixel_source", > > Shouldn't this be an atomic prop?
Acked.
> > >>> + hweight32(supported_sources)); >>> + >>> + if (!prop) >>> + return -ENOMEM; >>> + >>> + for (i = 0; i < ARRAY_SIZE(enum_list); i++) { >>> + int ret; >>> + >>> + if (!(BIT(enum_list[i].type) & supported_sources)) >> >> test_bit?
Acked.
>> >>> + continue; >>> + >>> + ret = drm_property_add_enum(prop, enum_list[i].type, enum_list[i].name); >>> + >> >> No need for an empty line in such cases. Please drop it.
Acked.
>> >>> + if (ret) { >>> + drm_property_destroy(dev, prop); >>> + >>> + return ret; >>> + } >>> + } >>> + >>> + drm_object_attach_property(&plane->base, prop, DRM_PLANE_PIXEL_SOURCE_FB); >>> + plane->pixel_source_property = prop; >>> + >>> + return 0; >>> +} >>> +EXPORT_SYMBOL(drm_plane_create_pixel_source_property); >>> diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h >>> index 0338a860b9c8..31af7cfa5b1b 100644 >>> --- a/include/drm/drm_blend.h >>> +++ b/include/drm/drm_blend.h >>> @@ -59,4 +59,6 @@ int drm_atomic_normalize_zpos(struct drm_device *dev, >>> int drm_plane_create_blend_mode_property(struct drm_plane *plane, >>> unsigned int supported_modes); >>> int drm_plane_create_solid_fill_property(struct drm_plane *plane); >>> +int drm_plane_create_pixel_source_property(struct drm_plane *plane, >>> + unsigned int supported_sources); >>> #endif >>> diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h >>> index f6ab313cb83e..73fb6cf8a5d9 100644 >>> --- a/include/drm/drm_plane.h >>> +++ b/include/drm/drm_plane.h >>> @@ -59,6 +59,12 @@ struct drm_solid_fill { >>> uint32_t b; >>> }; >>> >>> +enum drm_plane_pixel_source { >>> + DRM_PLANE_PIXEL_SOURCE_FB, >>> + DRM_PLANE_PIXEL_SOURCE_COLOR, >>> + DRM_PLANE_PIXEL_SOURCE_MAX >>> +}; > > Just to be very clear that I'm not confusing you with my comment about > UAPI headers in the previous patch, this enum is already in a good > place. It does not belong in a UAPI header, because userspace > recognises enum values by the name string.
Got it.
Thanks,
Jessica Zhang
> > > Thanks, > pq > >>> + >>> /** >>> * struct drm_plane_state - mutable plane state >>> * >>> @@ -152,6 +158,14 @@ struct drm_plane_state { >>> */ >>> struct drm_solid_fill solid_fill; >>> >>> + /* >>> + * @pixel_source: >>> + * >>> + * Source of pixel information for the plane. See >>> + * drm_plane_create_pixel_source_property() for more details. >>> + */ >>> + enum drm_plane_pixel_source pixel_source; >>> + >>> /** >>> * @alpha: >>> * Opacity of the plane with 0 as completely transparent and 0xffff as >>> @@ -742,6 +756,13 @@ struct drm_plane { >>> */ >>> struct drm_property *solid_fill_property; >>> >>> + /* >>> + * @pixel_source_property: >>> + * Optional pixel_source property for this plane. See >>> + * drm_plane_create_pixel_source_property(). >>> + */ >>> + struct drm_property *pixel_source_property; >>> + >>> /** >>> * @alpha_property: >>> * Optional alpha property for this plane. See >>> >> >
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