Looking to SConstruct file in latest release (2.4.0), i found mention, that custom CC, CFLAGS, CXXFLAGS are not supported by devs. Some other packages, like firefox and wine, have USE=custom-cflags. Would be good to add it to libffado too.
I'm not sure we need that USE flag. Sure, upstream does not support custom CFLAGS, but there's little *actual* reason for that to cause a problem (unless the upstream code is buggy). We enable CUSTOM_ENV already and honor user-supplied CFLAGS. The SConscript already warns users that this configuration is unsupported, so they should not submit bugs upstream. I'm happy to take bugs caused by custom CFLAGS as the Gentoo proxy-maintainer (and submit fixes upstream if there is a problem in the code, which there probably is if otherwise innocuous CFLAGS break things). Huge complicated packages like wine, firefox, chromium, and special stuff like bootloaders and EFI managers have good reason to be wary of custom CFLAGS. libffado is a tiny straightforward package in comparison, it should be fine defaulting to honoring user CFLAGS. Dare I say it's more likely that not honoring custom CFLAGS by default is more likely to break things for users with a good reason to use said CFLAGS, than it is for honoring some broken CFLAGS to break things in libffado but not other packages.
anyway, i was wrong, ffado is working great with Qt5+python3, the problem was a crashed ffado-dbus-server in background, and there is no warning about that launching a new server or mixer (perharps more a dbus behaviour than a true ffado bug).
Ah, yes, this is a common problem with ffado-mixer. If the hardware interface is disconnected or there is a problem, you need to kill ffado-dbus-server and restart ffado-mixer to let it relaunch it. It's an upstream issue. Anyway, I'll close this bug for now since I don't think we have a good reason for an explicit custom-cflags USE at this point.
