On Mon, 11 Nov 2024 at 10:08, Daniel P. Berrangé <berra...@redhat.com> wrote:
> On Sun, Nov 10, 2024 at 08:08:16AM +0100, Phil Dennis-Jordan wrote: > > On Sun 10. Nov 2024 at 08:01, Akihiko Odaki <akihiko.od...@daynix.com> > > wrote: > > > > > On 2024/11/08 23:46, Phil Dennis-Jordan wrote: > > > > macOS's Cocoa event handling must be done on the initial (main) > thread > > > > of the process. Furthermore, if library or application code uses > > > > libdispatch, the main dispatch queue must be handling events on the > main > > > > thread as well. > > > > > > > > So far, this has affected Qemu in both the Cocoa and SDL UIs, > although > > > > in different ways: the Cocoa UI replaces the default qemu_main > function > > > > with one that spins Qemu's internal main event loop off onto a > > > > background thread. SDL (which uses Cocoa internally) on the other > hand > > > > uses a polling approach within Qemu's main event loop. Events are > > > > polled during the SDL UI's dpy_refresh callback, which happens to run > > > > on the main thread by default. > > > > > > GTK should also do the same as SDL and requires treatment; I forgot to > > > note that in previous reviews. > > > > > > Although it‘s possible to build Qemu with GTK support enabled on macOS, > > that UI doesn’t actually work on macOS at all, and apparently hasn’t been > > supported since 2018, see: > > https://stackoverflow.com/a/51474795 > > > > I don’t think there’s any point making adjustments to the GTK code by > > guessing what might be needed if someone did fix that to work with macOS > at > > some point. > > If we don't support GTK on macOS, then we should update meson.build > to actively prevent users enabling GTK on macOS builds, rather than > letting them suffer random runtime crashes. > > Agreed - I'm now more confused than ever though because https://gitlab.com/qemu-project/qemu/-/issues/2539 sort of implies that Philippe has previously been using it successfully. Or perhaps this was created in response to https://gitlab.com/qemu-project/qemu/-/issues/2515 ? But it seems like even the SDL implementation isn't perfect: https://gitlab.com/qemu-project/qemu/-/issues/2537 Basically, it seems like Qemu's UI threading on macOS is currently a bit of a mess, except in the Cocoa UI.
