Cocoa display hangs on macOS 10.15 (Catalina)

[Shachar Itzhaky]

I have downloaded the latest stable source tarball 4.1.0 and compiled it (i386-softmmu target).

After opening a black window, QEMU hangs (spinning beach ball).
When building with `--disable-cocoa --enable-sdl`, display seems to work fine.

The same happened when I tried to build QEMU through HomeBrew and MacPorts.

[zenojevski (zenojevski)]

I am also affected by this after upgrading to 10.15 Catalina.

I experience the same behavior using `qemu-system-x86_64`, but I can't confirm whether other systems are also affected.

Building with SDL also fixed it for me so far:

* `brew edit`
* add `depends_on "sdl2"` among other dependencies
* replace `--enable-cocoa` with `--disable-cocoa`
* replace `--disable-sdl` with `--enable-sdl`
* save, quit, and `brew install --build-from-source qemu`

[Shachar Itzhaky (corwin-amber)]

I tried with `--enable-gtk` and it hangs as well.
Using gtk3 build from MacPorts with `+quartz`. Now, this may be a systemwide problem with Gtk, I am yet to test other Gtk apps on Catalina.

[Peter Maydell (pmaydell)]

Investigation/patches would be welcome. Only one or two active upstream QEMU devs use OSX, and certainly personally I don't propose to upgrade to Catalina for at least six months to a year or so.

[Peter Maydell (pmaydell)]

Hikaru Nishida kindly wrote a patch which should fix this:
https://<email address hidden>/

[Shachar Itzhaky (corwin-amber)]

This is wonderful! Thank you Peter and Hikaru for this patch. I will try it ASAP and confirm.

[Shachar Itzhaky (corwin-amber)]

Yes, works perfectly!

[Peter Maydell (pmaydell)]

Hikaru's patch is now in master as commit dff742ad27efa4, and will be in the next QEMU release.