On Wed, Apr 28, 2021 at 10:44:03AM +0300, Pekka Paalanen wrote: > On Wed, 28 Apr 2021 07:21:28 +0000 > Simon Ser <contact@xxxxxxxxxxx> wrote: > > > > A solution to make this configuration generic and exposed by the kernel > > > would standardise this across Linux > > > > Having a KMS property for this makes sense to me. > > > > Chatting with Jani on IRC, it doesn't seem like there's any EDID or > > DisplayID block for this. > > > > Note, Android exposes a data structure [1] with: > > > > - Margin of the cut-out for each edge of the screen > > - One rectangle per edge describing the cut-out region > > - Size of the curved area for each edge of a waterfall display > > > > I haven't found anything describing the rounded corners of the display. > > > > [1]: https://developer.android.com/reference/android/view/DisplayCutout > > Hi, > > I'm kind of worried whether you can design a description structure that > would be good for a long time. That list already looks quite > complicated. Add also watch-like devices with circular displays. > > Would the kernel itself use this information at all? > > If not, is there not a policy that DT is not a userspace configuration > store? If someone is sufficiently bored it would make sense to teach fbcon (but not fbdev I guess for full sized boot splash) to avoid the edges/corners for output. But also fbcon/fbdev is I think finally dead on Android, so the intersection of people who care about cut-outs and fbcon is likely 0. Otherwise I can't think of anything. > You mentioned the panel orientation property, but that is used by the > kernel for fbcon or something, is it not? Maybe as the default value > for the CRTC rotation property which actually turns the image? > > Assuming that you succeed in describing these non-usable, funny > (waterfall edge), funny2 (e.g. behind a shade or filter so visible but > not normal), funny3 (e.g. phone button area with maybe tactile > markings), and normal areas, how would userspace handle this > information? > > Funny2 and funny3 are hypothetical but maybe not too far-fetched. > > Is there any provision for generic userspace to handle this generically? > > This seems more like a job for the hypothetical liboutput, just like > recognising HMDs (yes, I know, kernel does that already, but there is a > point that kernel may not want to put fbcon on a HMD). I think the desktop linux solution would be hwdb entries, except we've never done this for anything display related. So yeah liboutput sounds about right for this :-) Btw on fbcon on HMD, I thought we're already taking care of that? -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
