On Wednesday, September 2, 2020 2:44 PM, Daniel Vetter <daniel.vetter@xxxxxxxx> wrote: > > I suppose something similar happens in user-space: gbm_bo_create > > without modifiers needs to properly set the implicit modifier, ie. > > gbm_bo_get_modifier needs to return the effective modifier. Is this > > something already documented? > > I don't think that happens, but it has come up in discussions. It's > kinda different scenario though: getfb2 is for cross-compositor stuff, > enabling smooth transitions at boot-up and when switching. So you have > a legit reason for mixing modifier-aware userspace with > non-modifier-aware userspace. And the modifier-aware userspace would > like that everything works with modifiers consistently, including > getfb2. But gbm is just within a single process, and that should > either run all with modifiers, or not at all, since these worlds just > dont mix well. Hence I'm not seeing much use for that, -modesetting > being a confused mess nonwithstanding :-) Well… There's also the case where some legacy Wayland client talks to a modifier-aware compositor. gbm_bo_import would be called without a modifier, but the compositor expects gbm_bo_get_modifier to work. Also, wlroots will call gbm_bo_create without a modifier to only let the driver pick "safe" modifiers in case passing the full list of modifiers results in a black screen. Later on wlroots will call gbm_bo_get_modifier to figure out what modifier the driver picked. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
