5 ms·

Seems to me like it might be a calibration issue, and third parties aren’t able to perform the calibration.

dataflow 3y ago
I have no way to verify this, but this Redditor claims it's due to the serial number being different, not calibration (also see the grandparent comment that they posted): https://www.reddit.com/r/gadgets/comments/15cxwaa/apple_pencils_cant_draw_straight_on_thirdparty/jtztu2g/ https://www.reddit.com/r/gadgets/comments/15cxwaa/apple_penc... That said, I see a generous explanation that I can't rule out based on what they're describing. It seems like the only test this Redditor mentioned was that you can modify the serial number and cause it to go from correct behavior to misbehavior. But I would think the reverse direction is the real test, since otherwise this could just imply that the device is looking up some embedded calibration information for that serial number and not finding it, and therefore falling back to some default behavior?
- KennyBlanken 3y ago
  That redditor says it's just serial number matching, complains at length about how this issue is destroying their business while in the same breath saying that reprogramming the screen's serial number on a working unit will bring up the same problem. So, if it's just a matching serial numbers problem, why aren't they programming the new screens with the serial number of the old screen, and thus the problem goes away?
  - dataflow 3y ago
    It's a reasonable question; I don't know the answer. It might require damaging the device too much to return it to the consumer at that point? Or maybe they can't due to contractual reasons? It might be worth asking them on Reddit.
  - realusername 3y ago
    That's exactly what their "calibration" procedure on iPhone does, it just changes the serial number pairing, nothing else, you don't even have to touch on the screen.
- turquoisevar 3y ago
  They have no clue what they’re talking about. They were a genius grunt and their penchant for drawing conclusions on incomplete information is exactly why they aren’t trusted to perform manual calibration that hinges on their manual interaction with the screen. If you read their other comments then you see that they believe that all components used are identical and thus wouldn’t need calibration. Never mind the fact that different vendors are used to supply screens depending on the model in question, even between “identical” screens there’s plenty of subtle variation. The controller holds calibration information in the form of offsets for touch and color amongst other things. The controller is married via serial numbers and if there’s a mismatch it’ll default to no offset. This also serves as a clear indicator, with other indicators, that calibration is needed in an effort to prevent the calibration from being forgotten. Despite not every screen being identical, the accepted tolerance makes it so that offsets for one screen are often “good enough” for another screen to the point most people won’t notice it’s not perfect, provided they’re from the same vendor. There’s no other super secret mystery to it.
sbalamurugan 3y ago
Apparently it is not. The reddit thread has an ex Apple employee who runs repair shops in Germany. He says if you just change the serial number of a iPad screen(using specialised hardware) in existing iPad this issue will appear. This seems to indicate that it’s intentionally done by Apple. Other option is that Apple bakes in calibration details of all possible serial numbers in every iPad sold which doesn’t sound like a plausible scenario.
- klausa 3y ago
  Why would the calibration details need to account for all iPads sold? Just bake the one that the device is bonded with, using the display serial number as a lookup key. Then, if you change the serial number of the display, the lookup would fail, and fall back to whatever "default" values are.
  - rasz 3y ago
    and just be shear coincident two screens, the broken one and replacement, match calibration data completely?
    - Too 3y ago
      Actually not that unlikely, imagine the allowed range of calibration is 0-100, the factory is likely to produce parts with small variance, but having same constant offset, resulting in output of screens between 70-80. While default in software might be set exactly in the middle at 50. Knowing how a large organization works, the default set in sw is probably not even close to what comes out of production lines, it's just an assumption some dev made that happened to work good enough on his desk 4 years ago. Even if the screens would cover the whole spectrum, there is still a high chance this coincidence could happen, and more data would be needed to validate either theory. Is there any statistics showing that this happens all the time or just some times.
- can16358p 3y ago
  Could it be something like this: At software level iOS registers some calibration data (after some factory calibration) tied to that specific serial number (as calibration makes sense only for that specific instance of the panel anyway) so when serial number changes iOS can't find calibration data on device and continues uncalibrated instead of trying to use calibrations for another-serial screen (from the OS perspective). It makes sense, if there actually is some sort of calibration going on in the first place of course.
hyperhopper 3y ago
> third parties aren’t able to perform the calibration. Which is an even bigger issue caused entirely by apples anti-competitive anti-user practices.

I have no way to verify this, but this Redditor claims it's due to the serial number being different, not calibration (also see the grandparent comment that they posted): https://www.reddit.com/r/gadgets/comments/15cxwaa/apple_pencils_cant_draw_straight_on_thirdparty/jtztu2g/ https://www.reddit.com/r/gadgets/comments/15cxwaa/apple_penc... That said, I see a generous explanation that I can't rule out based on what they're describing. It seems like the only test this Redditor mentioned was that you can modify the serial number and cause it to go from correct behavior to misbehavior. But I would think the reverse direction is the real test, since otherwise this could just imply that the device is looking up some embedded calibration information for that serial number and not finding it, and therefore falling back to some default behavior?

KennyBlanken 3y ago
That redditor says it's just serial number matching, complains at length about how this issue is destroying their business while in the same breath saying that reprogramming the screen's serial number on a working unit will bring up the same problem. So, if it's just a matching serial numbers problem, why aren't they programming the new screens with the serial number of the old screen, and thus the problem goes away?
- dataflow 3y ago
  It's a reasonable question; I don't know the answer. It might require damaging the device too much to return it to the consumer at that point? Or maybe they can't due to contractual reasons? It might be worth asking them on Reddit.
- realusername 3y ago
  That's exactly what their "calibration" procedure on iPhone does, it just changes the serial number pairing, nothing else, you don't even have to touch on the screen.
turquoisevar 3y ago
They have no clue what they’re talking about. They were a genius grunt and their penchant for drawing conclusions on incomplete information is exactly why they aren’t trusted to perform manual calibration that hinges on their manual interaction with the screen. If you read their other comments then you see that they believe that all components used are identical and thus wouldn’t need calibration. Never mind the fact that different vendors are used to supply screens depending on the model in question, even between “identical” screens there’s plenty of subtle variation. The controller holds calibration information in the form of offsets for touch and color amongst other things. The controller is married via serial numbers and if there’s a mismatch it’ll default to no offset. This also serves as a clear indicator, with other indicators, that calibration is needed in an effort to prevent the calibration from being forgotten. Despite not every screen being identical, the accepted tolerance makes it so that offsets for one screen are often “good enough” for another screen to the point most people won’t notice it’s not perfect, provided they’re from the same vendor. There’s no other super secret mystery to it.

sbalamurugan 3y ago

Apparently it is not. The reddit thread has an ex Apple employee who runs repair shops in Germany. He says if you just change the serial number of a iPad screen(using specialised hardware) in existing iPad this issue will appear. This seems to indicate that it’s intentionally done by Apple. Other option is that Apple bakes in calibration details of all possible serial numbers in every iPad sold which doesn’t sound like a plausible scenario.

klausa 3y ago
Why would the calibration details need to account for all iPads sold? Just bake the one that the device is bonded with, using the display serial number as a lookup key. Then, if you change the serial number of the display, the lookup would fail, and fall back to whatever "default" values are.
- rasz 3y ago
  and just be shear coincident two screens, the broken one and replacement, match calibration data completely?
  - Too 3y ago
    Actually not that unlikely, imagine the allowed range of calibration is 0-100, the factory is likely to produce parts with small variance, but having same constant offset, resulting in output of screens between 70-80. While default in software might be set exactly in the middle at 50. Knowing how a large organization works, the default set in sw is probably not even close to what comes out of production lines, it's just an assumption some dev made that happened to work good enough on his desk 4 years ago. Even if the screens would cover the whole spectrum, there is still a high chance this coincidence could happen, and more data would be needed to validate either theory. Is there any statistics showing that this happens all the time or just some times.
can16358p 3y ago
Could it be something like this: At software level iOS registers some calibration data (after some factory calibration) tied to that specific serial number (as calibration makes sense only for that specific instance of the panel anyway) so when serial number changes iOS can't find calibration data on device and continues uncalibrated instead of trying to use calibrations for another-serial screen (from the OS perspective). It makes sense, if there actually is some sort of calibration going on in the first place of course.

hyperhopper 3y ago

> third parties aren’t able to perform the calibration. Which is an even bigger issue caused entirely by apples anti-competitive anti-user practices.