Re: [PATCH RFC v5 02/10] drm: Introduce solid fill DRM plane property
From: Jessica Zhang
Date: Mon Aug 28 2023 - 19:46:41 EST
On 8/8/2023 3:57 PM, Jessica Zhang wrote:
On 8/7/2023 6:07 PM, Dmitry Baryshkov wrote:
On 8 August 2023 00:41:07 GMT+03:00, Jessica Zhang
<quic_jesszhan@xxxxxxxxxxx> wrote:
On 8/4/2023 6:27 AM, Dmitry Baryshkov wrote:
On Fri, 28 Jul 2023 at 20:03, Jessica Zhang
<quic_jesszhan@xxxxxxxxxxx> 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@xxxxxxxxxxx>
---
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.
That depends on the blending mode: in Coverage mode one has
independent plane and contents alpha values. And I consider alpha
value to be a part of the colour in the rgba/bgra modes.
Acked -- taking Sebastian's concern into consideration, I think I'll
have "PIXEL_SOURCE_SOLID_FILL_RGB" and add a separate
"PIXEL_SOURCE_SOLID_FILL_RGBA".
Hi Dmitry,
Since it looks like there's still some ongoing discussion with Pekka
about whether to support an RGBA solid fill source, I'll just leave a
note to add an RGBA source in the future.
Thanks,
Jessica Zhang
Thanks,
Jessica Zhang
Thanks,
Jessica Zhang
--
With best wishes
Dmitry
--
With best wishes
Dmitry