Messages in this thread | | | Date | Mon, 7 Aug 2023 14:41:07 -0700 | Subject | Re: [PATCH RFC v5 02/10] drm: Introduce solid fill DRM plane property | From | Jessica Zhang <> |
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On 8/4/2023 6:27 AM, Dmitry Baryshkov wrote: > On Fri, 28 Jul 2023 at 20:03, Jessica Zhang <quic_jesszhan@quicinc.com> wrote: >> >> Document and add support for solid_fill property to drm_plane. In >> addition, add support for setting and getting the values for solid_fill. >> >> To enable solid fill planes, userspace must assign a property blob to >> the "solid_fill" plane property containing the following information: >> >> struct drm_mode_solid_fill { >> u32 version; >> u32 r, g, b; >> }; >> >> Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com> >> --- >> drivers/gpu/drm/drm_atomic_state_helper.c | 9 +++++ >> drivers/gpu/drm/drm_atomic_uapi.c | 55 +++++++++++++++++++++++++++++++ >> drivers/gpu/drm/drm_blend.c | 30 +++++++++++++++++ >> include/drm/drm_blend.h | 1 + >> include/drm/drm_plane.h | 35 ++++++++++++++++++++ >> include/uapi/drm/drm_mode.h | 24 ++++++++++++++ >> 6 files changed, 154 insertions(+) >> > > [skipped most of the patch] > >> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h >> index 43691058d28f..53c8efa5ad7f 100644 >> --- a/include/uapi/drm/drm_mode.h >> +++ b/include/uapi/drm/drm_mode.h >> @@ -259,6 +259,30 @@ struct drm_mode_modeinfo { >> char name[DRM_DISPLAY_MODE_LEN]; >> }; >> >> +/** >> + * struct drm_mode_solid_fill - User info for solid fill planes >> + * >> + * This is the userspace API solid fill information structure. >> + * >> + * Userspace can enable solid fill planes by assigning the plane "solid_fill" >> + * property to a blob containing a single drm_mode_solid_fill struct populated with an RGB323232 >> + * color and setting the pixel source to "SOLID_FILL". >> + * >> + * For information on the plane property, see drm_plane_create_solid_fill_property() >> + * >> + * @version: Version of the blob. Currently, there is only support for version == 1 >> + * @r: Red color value of single pixel >> + * @g: Green color value of single pixel >> + * @b: Blue color value of single pixel >> + */ >> +struct drm_mode_solid_fill { >> + __u32 version; >> + __u32 r; >> + __u32 g; >> + __u32 b; > > Another thought about the drm_mode_solid_fill uABI. I still think we > should add alpha here. The reason is the following: > > It is true that we have drm_plane_state::alpha and the plane's > "alpha" property. However it is documented as "the plane-wide opacity > [...] It can be combined with pixel alpha. The pixel values in the > framebuffers are expected to not be pre-multiplied by the global alpha > associated to the plane.". > > I can imagine a use case, when a user might want to enable plane-wide > opacity, set "pixel blend mode" to "Coverage" and then switch between > partially opaque framebuffer and partially opaque solid-fill without > touching the plane's alpha value.
Hi Dmitry,
I don't really agree that adding a solid fill alpha would be a good idea. Since the intent behind solid fill is to have a single color for the entire plane, I think it makes more sense to have solid fill rely on the global plane alpha.
As stated in earlier discussions, I think having both a solid_fill.alpha and a plane_state.alpha would be redundant and serve to confuse the user as to which one to set.
Thanks,
Jessica Zhang
> > -- > With best wishes > Dmitry
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