On Thu, Jun 07, 2018 at 08:01:23AM +0200, Gerd Hoffmann wrote: > On Wed, Jun 06, 2018 at 02:49:24PM +0200, Erik Skultety wrote: > > On Tue, Jun 05, 2018 at 11:52:03AM +0200, Gerd Hoffmann wrote: > > > Hi, > > > > > > > > TL;DR: > > > > > - we have a new attribute value for vfio-pci mediated devices called 'display' > > > > > -> devices can now format this new 'display=on/off' property to the cmdline > > > > > > Good. > > > > > > > > - if user enables the vfio display (display=on) but doesn't enable OpenGL for > > > > > Spice, we automatically assume the usage of '-display egl-headless' > > > > > > Hmm, I think it would be better to have egl-headless explicitly > > > configured in the domain xml instead of doing it automagically depending > > > on configuration. > > > > I was thinking about that earlier, then we had a private conversation where I > > asked why there's no documentation on egl-headless in QEMU to which you replied > > that the future of egl-headless being uncertain, especially once there's remote > > opengl renderer support (as opposed to local nowadays). So I took a bit of a > > safe path here and only made the changes to the command line, thus leaving us > > with a way of easily ditching that if QEMU decides to deprecate egl-headless > > completely. So, if QEMU can guarantee supporting egl-headless (of course you > > can discourage usage of it...) then we surely can expose it through the XML, > > Well, I guess if libvirt uses it it pretty much has to stay anyway ... It would be beneficial to add it to the man page and/or --help output then. > > It isn't much of a burden code-wise, most of the underlying egl/opengl > code is needed for -spice gl=on too. It is just that once spice got > remote support for gl=on mode it is alot less useful because native > spice support clearly is the better route performance-wise. > > > egl-headless was introduced in 2.10 IIRC, but I don't see any way for libvirt > > to use any kind of introspection here, there's no capability for egl-headless, > > Yea, right, isn't there. > > > I see it defined as a value for DisplayType in the qapi scheme (ui.json), but > > I don't see any query command. > > Also the enum is alwayws present, no matter whenever qemu was compiled > with opengl support or not. So even in case you could query it it > wouldn't buy you anything. In which case the only thing we can do is let qemu fail with an internal error rather than failing in libvirt because of a missing capability. > > How is spice/vnc support probed for btw? we execute 'query-commands' and then looking for in "query-spice" and "query-vnc" literals in the list of returned commands. Erik -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
