On Wed, Nov 09, 2022 at 04:53:45PM +0300, Dmitry Baryshkov wrote: > On 09/11/2022 16:52, Daniel Vetter wrote: > > On Tue, Nov 08, 2022 at 06:25:29PM +0000, Simon Ser wrote: > > > On Saturday, October 29th, 2022 at 13:23, Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> wrote: > > > > > > > On 29/10/2022 01:59, Jessica Zhang wrote: > > > > > > > > > Add support for COLOR_FILL and COLOR_FILL_FORMAT properties for > > > > > drm_plane. In addition, add support for setting and getting the values > > > > > of these properties. > > > > > > > > > > COLOR_FILL represents the color fill of a plane while COLOR_FILL_FORMAT > > > > > represents the format of the color fill. Userspace can set enable solid > > > > > fill on a plane by assigning COLOR_FILL to a uint64_t value, assigning > > > > > the COLOR_FILL_FORMAT property to a uint32_t value, and setting the > > > > > framebuffer to NULL. > > > > > > > > I suppose that COLOR_FILL should override framebuffer rather than > > > > requiring that FB is set to NULL. In other words, if color_filL_format > > > > is non-zero, it would make sense to ignore the FB. Then one can use the > > > > color_fill_format property to quickly switch between filled plane and > > > > FB-backed one. > > > > > > That would be inconsistent with the rest of the KMS uAPI. For instance, > > > the kernel will error out if CRTC has active=0 but a connector is still > > > linked to the CRTC. IOW, the current uAPI errors out if the KMS state > > > is inconsistent. > > > > So if the use-case here really is to solid-fill a plane (and not just > > provide a background color for the crtc overall), then I guess we could > > also extend addfb to make that happen. We've talked in the past about > > propertery-fying framebuffer objects, and that would sort out this uapi > > wart. And I agree the color fill vs PLANE_ID issue is a bit ugly at least. > > > > But if the use-cases are all background color then just doing the crtc > > background color would be tons simpler (and likely also easier to support > > for more hardware). > > No. The hardware supports multiple color-filled planes, which do not have to > cover the whole CRTC. The use case here means the userspace use-case. What the hw can do on any given chip kinda doesnt matter, which is why I'm asking. KMD uapi is not meant to reflect 100% exactly what a specific chip can do, but instead: - provide features userspace actually needs. If you want per-plane fill, you need userspace that makes use of per-plane fill, and if all you have is crtc background, then that's it. - we should create uapi with an eye towards what's actually possible on a reasonable set of drivers and hw. Sometimes that means a slightly more restricted set so that it's possible to implement in more places, especially if that restricted feature set still gets the job done for userspace. Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
