Audio mixer doesn't save per-app output levels anymore

[humdinger]

This is hrev56563, 64bit.

The audio mixer of the Media preferences used to save the output level of individual applications. I checked with 32bit Beta3, it works there (maybe someone else cancheck if it worked for 64bit Beta3 as well).

• Open Media prefs, go to "Audio mixer" section.
• Start some SDL game (Lbreakout2 in my case) and you get an output level slider for "SDL audio". Or start MediaPlayer with some MP3 and you get a slider "MediaPlayer audio out".

You can adjust the output level, close the apps and the sliders disappear. When you re-open the apps, they should restore the previously set output level. They did on Beta3, not anymore.

[korli]

Could you refine the regression range? hrev55181-hrev56563 makes 1500 revisions.

The diffs don't really show anything useful.

​https://cgit.haiku-os.org/haiku/diff/src/add-ons/media/media-add-ons/mixer?id2=r1beta3

​https://cgit.haiku-os.org/haiku/diff/src/servers/media?id2=r1beta3

​https://cgit.haiku-os.org/haiku/diff/src/servers/media_addon?id2=r1beta3

​https://cgit.haiku-os.org/haiku/diff/src/kits/media?id2=r1beta3

[humdinger]

I guess I should've asked first if anyone can reproduce the issue.

I've now painstakingly binary search nightlies from beta3 to my hrev56563. All working fine...

Now, what on earth could mess up my "production" system compared to the pristine nightly? I have no idea. I checked the "/boot/home/config/settings/System Audio Mixer" file's modified date. Something does get written. Only the MediaPlayer's channel gain is always the same 0.8712. Output from the "message" command:

        input[4] = BMessage(0x0) {
                lru = int64(0xe3c4e71 or 238833265)
                name = string("MediaPlayer audio out", 22 bytes)
                InputChannelCount = int32(0x2 or 2)
                InputIsEnabled = bool(true)
                InputChannelGain[0] = float(0.8712)
                InputChannelGain[1] = float(0.8712)
        }

Stumped.