HDMI audio prevents screen saver, still

MacOS 10.12 still has the ridiculous bug that if your system audio output is set to HDMI, and iTunes is playing, then the screen saver will never activate and your screen will never lock.

In 10.8 through 10.10, the fix for this was to hack the coreaudiod binary.

In 10.11, the system wouldn't run the new coreaudiod unless it was signed. Solution: sign it with your own key, because they accepted any signature.

Well, in 10.12, that doesn't work any more. Copy the executable and it works; re-sign it and it doesn't. Presumably they are checking for an Apple signature now.

Any ideas of another workaround?

I happen to like having my machine be secure even if it happens to be playing music. How weird.

Previously, previously, previously.

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19 Responses:

  1. file a bug?

    yes, apple wants you to pay to make that possible. Still, it is possible.

    • Pavel says:

      Apple charges you to file bugs?

      • For direct access, yes, you need to be a registered and paying developer. But all that let's you do is file a bug that they'll ignore.

        The "whine on Twitter" approach may actually work some of the time (https://twitter.com/0x6772/status/781888580230733824 -- I have an outstanding case open about that, through AppleCare support, resulting from that tweet), but not all of the time (https://twitter.com/0x6772/status/782274488054456320 -- I kind of figure enough other people have bitched at them directly about that, so either it'll get a bugfix some time soon or just be ignored forever, like this dumb HDMI audio thing).

        • ghostly_s says:

          You do not need a paid developer account to file a Radar, to my recollection you never have. I just filed one this week and I've never paid for a dev account; any old Apple ID will do. I believe they recently discontinued the 'free' dev accounts that previously were required for access to this, and some of the access you used to get with a free account were removed, but Bugreport is more open than it ever was before (and don't forget Openradar, too).

          • Huh. Okay, great! I'm happy to be wrong about that!

            I still don't get the impression that they pay attention to Radar bug reports about glaring issues very well, but that's good to know.

      • Wouter says:

        Apple charges you to get a developer account. A developer account is the only way to file bugs against their OS.

    • jwz says:

      The perennial "File a bug?" comment is why we need a protocol to deliver cockpunches through the internet.

      • ATB says:

        The current protocol only supports creating a cock-shaped soundwave and plunging it repeatedly through their skulls.

      • ghostly_s says:

        Wait, so you've been hacking a system binary and complaining about this for four years and haven't bothered to inform Apple of the bug? (I am happy to accept my cockpunch via US post, please email for address.)

        • jwz says:

          Wait, so I asked a specific question about a specific actual problem, and you decided to waste everyone's time by posting your theories of how it "ought" to be? Thanks for that.

          I could justify my opinion of the worthlessness of Apple's bug reporting mechanism to you, but you know what? I don't want to. And that's not the point of this post.

      • Wouter says:

        My point is that I agree with you that the described behavior is stupid, and that I think any reasonable person would agree. If that assumption is correct, then filing a bug would get you a fix and stop requiring that you apply workarounds. I agree that filing bugs isn't always a useful use of one's time, but in this case, per my gut feeling, that would not seem to apply.

        Since we're on the subject of workarounds: it is possible to switch off that security thing in macOS which now requires signed binaries through some magic switch somewhere (I don't know the details; personally I don't use any Macs, but I have colleagues who do). If you switch that off, it seems reasonable to assume that the old workaround which you used before would still work. Obviously I wouldn't recommend that, but you did ask for workarounds, not for proper solutions...

  2. Ewen McNeill says:

    From memory your problem is that this (display won't lock) problem happens even when only audio (not video) is playing. Which, I agree, seems stupid.

    If you're willing to consider a hardware solution to the problem, perhaps audio over AirPlay could made to work in your scenario? AFAICR at least in OS X 10.9, iTunes playing audio over AirPlay still allows the display to lock. Obviously this would require something to receive the AirPlay (for which I'm sure Apple would like to sell you an Apple AirPort or maybe an Apple TV, but I've seen other things claim to receive AirPlay audio) -- and that thing be connected to suitable speakers/amp/mixer/switcher.

    (Yes, this does fall into the category of "kludgy work around for software bug"; sorry.)


    • jwz says:

      Yes, it prevents screen blanking when audio only is playing over the HDMI connection between my Mac and my AV receiver.

      The receiver does support Airplay, audio only, but that means having to jump through hoops when I switch between listening to music and watching movies. Also, Airplay is a big steaming pile of flaky unreliable shit. So no.

      Perhaps I could convince the receiver to take video from HDMI while taking corresponding audio from Toslink, but that's fucking stupid.

      • Keith says:

        There are HDMI video + TOSLINK combiners. They probably won't support HDCP so you might end up with a brand new set of problems you don't care for.

  3. mdhughes says:

    Only solution I know of is manually locking screen with Keychain Access (turn on "menu bar" in its preferences).

    • The whole point of screen saver locking is so that you don't have to do this manually.

      • Actually, the whole point of screen SAVERS is so that you don't have to do this manually. Who in their right mind is still using a CRT? (Er, well, actually, I have a Mac Mini attached to one, but I never turn the screen on.)

        • mdhughes says:

          Screen savers now are art that happens on a locked screen. Having to start it by hand is stupid but at least it works, which is most of my interactions with technology anymore.

  4. okano says:

    Have you considered polling the HIDIdleTime counter from a script and locking the screen if it exceeds a threshold?

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