4 ms·

> We do not understand how Apple managed to release an OS update that, when upgraded to normally, leaves machines unbootable if their display refresh rate is no

> We do not understand how Apple managed to release an OS update that, when upgraded to normally, leaves machines unbootable if their display refresh rate is not the default. This seems to have been a major QA oversight by Apple. This sounds like a very weird edge case and it's very easy to say this sort of statement in retrospect, but I wonder what percentage of engineers would think of testing this specific combo beforehand.

leonheld 3y ago
> This sounds like a very weird edge case and it's very easy to say this sort of statement in retrospect As someone who works on embedded devices with a lot of experience with Hardware-in-the-loop testing, this is 100% a QA oversight. The way this feature is implemented screams "test it from boot to reboot". I wouldn't pick too much on a small company doing some basic BSP/application work for some HMI device or something like that, but this is the richest company in the world with major funds/infrastructure to be better than this.
- antoineMoPa 3y ago
  > The way this feature is implemented screams Do we have info about the implementation somewhere?
  - stevenhuang 3y ago
    Yes, we know the setting is persisted by storing the display configuration in nvram.
phkahler 3y ago
>> This sounds like a very weird edge case It's a single setting prior to a standard update. Now I'm not saying they should test every combination of settings, or even every individual setting. I'm more curious how there is any interplay between this setting and the update, and why that has any effect. On the surface it smells like a system design issue to me - like something is going in there on that shouldn't be.
- Wowfunhappy 3y ago
  > I'm more curious how there is any interplay between this setting and the update, and why that has any effect. On the surface it smells like a system design issue to me - like something is going in there on that shouldn't be. There is (probably) a logic behind it. https://mstdn.social/@marcan@treehouse.systems/111329614110191891 https://mstdn.social/@marcan@treehouse.systems/1113296141101... > Why [does disabling ProMotion cause this problem]? I can tell you why: because Apple hates display modeset flicker, and switching modes between ProMotion on/off causes a modeset flicker, so of course they made it so that is stored in nvram somewhere and applied when the screen is turned on during early boot, so when macOS boots it doesn't have to flicker again.
  - userbinator 3y ago
    In other words, Apple was so insistent on one tiny aesthetic point that it ended up breaking things for a lot of others who likely didn't care at all?
    - Wowfunhappy 3y ago
      Well, only because there was a bug. I personally appreciate how Apple prioritizes these little details—and I'd argue it's a huge part of what has made the company successful. This is the company that put a speaker in the iPod just to have a clicking sound for the scroll wheel.
    - tgma 3y ago
      I think the polish matters, especially considering that the majority of users with the default setting will be just fine appreciating the benefit. It wasn't intended to be a trade-off either. Just an unfortunate side effect of the additional complexity. It's accurate to cast it as an engineering tradeoff between complexity and aesthetics but IMO would be wrong to say they broke for a certain set of users in favor of aesthetics.
iAMkenough 3y ago
All it would take to find this bug is trying the install the update with an external Studio Display connected to a Mac with a built-in ProMotion display. Not even a third-party external display, just the display Apple currently sells along with the Mac Studio.
LASR 3y ago
Why would this be a very weird edge case on a professional machine? For context, I hate it when the built-in display is not consistent with my external displays. Few displays actually support ProMotion rates. So chances are that if you use any external display, you’ll have this jarring asymmetry. So you’ll want to set your rates manually. Using an external display with your MBP doesn’t seem like a weird edge case to me.
- BearOso 3y ago
  Lots of displays support 120Hz or above. That's actually something Apple has been late to the party with. On the other hand, Apple has problems with the M series chips and high refresh rate mode timings on external displays, so you're technically correct about the compatibility.

leonheld 3y ago

> This sounds like a very weird edge case and it's very easy to say this sort of statement in retrospect As someone who works on embedded devices with a lot of experience with Hardware-in-the-loop testing, this is 100% a QA oversight. The way this feature is implemented screams "test it from boot to reboot". I wouldn't pick too much on a small company doing some basic BSP/application work for some HMI device or something like that, but this is the richest company in the world with major funds/infrastructure to be better than this.

antoineMoPa 3y ago
> The way this feature is implemented screams Do we have info about the implementation somewhere?
- stevenhuang 3y ago
  Yes, we know the setting is persisted by storing the display configuration in nvram.

phkahler 3y ago

>> This sounds like a very weird edge case It's a single setting prior to a standard update. Now I'm not saying they should test every combination of settings, or even every individual setting. I'm more curious how there is any interplay between this setting and the update, and why that has any effect. On the surface it smells like a system design issue to me - like something is going in there on that shouldn't be.

Wowfunhappy 3y ago
> I'm more curious how there is any interplay between this setting and the update, and why that has any effect. On the surface it smells like a system design issue to me - like something is going in there on that shouldn't be. There is (probably) a logic behind it. https://mstdn.social/@marcan@treehouse.systems/111329614110191891 https://mstdn.social/@marcan@treehouse.systems/1113296141101... > Why [does disabling ProMotion cause this problem]? I can tell you why: because Apple hates display modeset flicker, and switching modes between ProMotion on/off causes a modeset flicker, so of course they made it so that is stored in nvram somewhere and applied when the screen is turned on during early boot, so when macOS boots it doesn't have to flicker again.
- userbinator 3y ago
  In other words, Apple was so insistent on one tiny aesthetic point that it ended up breaking things for a lot of others who likely didn't care at all?
  - Wowfunhappy 3y ago
    Well, only because there was a bug. I personally appreciate how Apple prioritizes these little details—and I'd argue it's a huge part of what has made the company successful. This is the company that put a speaker in the iPod just to have a clicking sound for the scroll wheel.
  - tgma 3y ago
    I think the polish matters, especially considering that the majority of users with the default setting will be just fine appreciating the benefit. It wasn't intended to be a trade-off either. Just an unfortunate side effect of the additional complexity. It's accurate to cast it as an engineering tradeoff between complexity and aesthetics but IMO would be wrong to say they broke for a certain set of users in favor of aesthetics.

iAMkenough 3y ago

All it would take to find this bug is trying the install the update with an external Studio Display connected to a Mac with a built-in ProMotion display. Not even a third-party external display, just the display Apple currently sells along with the Mac Studio.

LASR 3y ago

Why would this be a very weird edge case on a professional machine? For context, I hate it when the built-in display is not consistent with my external displays. Few displays actually support ProMotion rates. So chances are that if you use any external display, you’ll have this jarring asymmetry. So you’ll want to set your rates manually. Using an external display with your MBP doesn’t seem like a weird edge case to me.

BearOso 3y ago
Lots of displays support 120Hz or above. That's actually something Apple has been late to the party with. On the other hand, Apple has problems with the M series chips and high refresh rate mode timings on external displays, so you're technically correct about the compatibility.