On Tue, Apr 27, 2021 at 10:40:24AM +0300, Pekka Paalanen wrote: > On Mon, 26 Apr 2021 14:30:53 -0300 > Leandro Ribeiro <leandro.ribeiro@xxxxxxxxxxxxx> wrote: > > > On 4/26/21 7:58 AM, Simon Ser wrote: > > > On Monday, April 26th, 2021 at 9:36 AM, Pekka Paalanen <ppaalanen@xxxxxxxxx> wrote: > > > > > >>>> This should probably explain what the bits in the mask correspond to. > > >>>> As in, which CRTC does bit 0 refer to, and so on. > > >>> > > >>> What about: > > >>> > > >>> "possible_crtcs: Bitmask of CRTC's compatible with the plane. CRTC's are > > >>> created and they receive an index, which corresponds to their position > > >>> in the bitmask. CRTC with index 0 will be in bit 0, and so on." > > >> > > >> This would still need to explain where can I find this index. > > > > > > > What do you mean? > > > > > This closed merge request had some docs about possible CRTCs: > > > > > > https://gitlab.freedesktop.org/mesa/drm/-/merge_requests/102 > > > > > I'm afraid I don't know exactly what you expect to be documented here > > that is still missing. Could you please elaborate? > > > > Thanks a lot! > > The documentation you add is talking about "CRTC index". What defines a > CRTC object's index? How do I determine what index a CRTC object has? > > The answer is, AFAIK, that the index is never stored explicitly > anywhere. You have to get the DRM resources structure, which has an > array for CRTC IDs. The index is the index to that array, IIRC. So if > one does not already know this, it is going to be really hard to figure > out what the "index" is. It might even be confused with the object ID, > which it is not but the ID might by complete accident be less than 32 > so it would look ok at first glance. > > If the index is already explained somewhere else, a reference to that > documentation would be enough. I think if we do this we should have a DOC: section in the drm_mode.h uapi header which explains how the index is computed, and then we reference that everywhere. Because otherwise there's going to be a _lot_ of duplication of this all over. Kernel-internally we solve this by just referencing drm_foo_index() family of functions, but for the uapi there's really nothing, so needs text. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
