On Mon, Jan 13, 2020 at 11:41:45AM +0100, Dmitry Sepp wrote: > Hi Gerd, > > Thanks for reviewing! > > On Montag, 13. Januar 2020 10:56:36 CET Gerd Hoffmann wrote: > > Hi, > > > > > This also means that we cannot have unspec for planes layout. Device > > > either > > > expects planes in separate buffers or in one buffer with some offsets, > > > there cannot be mixed cases. > > > > Hmm. Is it useful to support both? Or maybe support the "one buffer + > > offsets" case only? Splitting one buffer into multiple smaller ones > > internally if needed shouldn't be a problem, and it would simplify the > > interface a bit ... > > > > Ok, let's consider the following case: > - the device expects planes in separate buffers. > - say, Android on the guest side also imports planes in separate buffers into the driver. > - but he driver only supports one buffer + offsets. > > Do you mean the driver then can join the underlying page lists and set offsets then? Yes, > this would probably make sense. Well, no. Tomasz Figa had splitted the devices into three groups: (1) requires single buffer. (2) allows any layout (including the one (1) devices want). (3) requires per-plane buffers. Category (3) devices are apparently rare and old. Both category (1)+(2) devices can handle single buffers just fine. So maybe support only that? Hope it's more clear this time, Gerd
