On Fri, Oct 24, 2014 at 05:25:58PM +1000, Dave Airlie wrote: > >> > > There are also configurations where users configure multiple heads to > >> > > drive power walls that they want to be treated as one logical monitor, > >> > > similar to the DP MST tiled display case. Normally, those powerwall > >> > > configurations don't have any layout information from the monitors > >> > > themselves, and the layout is configured by the user. > >> > > > >> > > Would it be appropriate for users to be able to set the TILE property > >> > > in that sort of scenario? > >> > > > >> > > For the sake of generality, I wonder if max[hv]tiles and [hv]_tile_loc > >> > > should be expressed in pixels rather than tiles? Sometimes, the tiles > >> > > in those powerwalls may not all have the same resolution, or may be > >> > > configured with overlap. I suppose that would make the TILE configuration > >> > > specific to the current modetimings on each tile... > >> > > >> > Why can't users just set that mode? > >> > >> Sure, users can set the mode, but: > >> > >> * Part of what the TILE property conveys is how monitors should be grouped > >> for purposes of window maximization. Users don't have a great way to > >> express that today, that I'm aware of. > > > > My understanding for why we want the TILE property is to avoid to > > duplicate displayId parsing over every bit of userspace (and the fbcon > > stuff in the kernel) interested in it. Imo the proper way for userspace is > > to always just inherit whatever modeset config is already there. > > Andy's idea is good, I'd considered it before, the problem being how > to expose it nicely, > > not sure if you'd want persistent via /sys or dynamic setting of the > property by user for that session, so we could do it like xrandr > modes. > > Daniel you are missing the nice case of using TILE for non-displayid > monitors once the infrastructure is in place. > > Having it so you can create user defined tile groups to allow users to > configure arbitrary walls is a useful thing, that you can't do any > other way. > > > > >> * Users might configure the mode they want, but then gnome-settings-daemon > >> may come along later and decide it knows better than the user how things > >> should be configured. One scenario where this comes up is: > >> (a) user meticulously configures his power wall > >> (b) user hotplugs another monitor > >> I've definitely seen cases where window managers will try to be clever > >> in response to a hotplug, and clobber the user's current configuration. > >> If the TILE property conveyed how some set of monitors was supposed > >> to be grouped, that would hopefully give window managers additional > >> information, such that they would know to keep that group intact. > > > > Well, imnsho gnome display control center is a bit too opiniated about > > automatic modeset changes. If their assumption is that they always know > > perfectly what the user wants upon hotplug I really don't want to work > > around this in the kernel. Since for everything else than a laptop + > > beamer gnome panel always pisses me off ;-) > > > > I think gnome should just ask the user what it wants if there's more than > > 2 physical displays (treating a tiled 4k screen as one ofc), since there's > > really no way at all to tell. > > Well its not just a GNOME problem either, once things like SDL respect > tIle properrty, > we can create arbitary tile walls that the whole stack will respect, > instead of hacks > like fake xinerama. Hm yeah if we want tile walls als logical displays for full-screening and all that then this makes indeed sense. I didn't really consider that part, was probably thrown off by Andy's comments that some tile walls aren't pixel aligned which would look funky for full-screen apps I guess. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
