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0 pointspmjordan14y ago0 comments

I don't know about "disasters". For better or worse, lots of software ships with severe bugs that are evidently rare enough never to be fixed but do happen.

For example, every few months, OSX kernel panics on my MacBook Air, with no obvious trigger. The backtrace always implicates the AHCI driver for the SATA SSD. Still, Apple evidently don't receive enough crash reports for this particular bug to actually fix it, as it's happened since I first bought the Air in November 2010.

I have no idea whether it's a threading bug like the one in the article (I'm not about to run my system in single-core mode for months just to find out) or maybe a race condition with DMA or just a simple logic error that only rarely applies. It might even be specific to the exact SSD model and revision I ended up with in my device. But that's pretty much irrelevant - there certainly hasn't been a widespread outcry about it.

Personally, as a developer, I would definitely want to fix that kind of bug in anything I'd built. But tracking it down might take weeks of costly developer time. So Apple's bug triage probably marked this one "WONTFIX" after deciding it only happened on hardware they no longer sell, so fixing it wasn't going to have a positive ROI.

(FWIW, if it sounds like I have a personal vendetta against the AHCI driver, that's because I do. ;-) It behaves erratically in ways unrelated to this crash, but that weirdness doesn't cause kernel panics, just extra work for developers of other drivers.)

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5 comments · 1 top-level

aptwebapps14y ago· 4 in thread

Going on a little (actually really long) tangent here about Apple and the general inscrutableness of their bug fixing ...

I have a late 2008 MBP from the first batch of unibodies and after having it for a few months I started getting this thing where the screen would blink. A lot other people did as well because by mid-2009 the relevant thread on their forum ran to over 75 pages so they had to be completely aware of it. People even put up youtube videos of it in action, which must have been a little tricky to catch because it was completely random.

In that thread on the forum some people told how they had managed to get their machines replaced. Sometimes the replaced machines had the defect as well. I never had any luck with my local support as they basically said they couldn't reproduce it so they couldn't replace it.

However, at one point a rookie tech left a support manual in pdf form on my machine after I had taken it in for servicing. There was a table in it which listed about a dozen different types of problems and the recommended approach for each. Which type of problem was the only one to have a blank cell where the solution should have been? Flickering or blinking displays.

So every time I had some other issue with my MBP, and I had several, I tried to get them to do something about the blinking problem. I finally got a second-tier support person (on the phone) to accept the issue. He said it had happened to his as well and replacing the Airport card (which happened to be the thing that had failed that particular time) had fixed it. This was about two months before the end of my three-year Apple Care period and he said that if that didn't fix it, he would try to get it replaced.

Well it didn't, to my utter lack of surprise, but I couldn't manage the hassle of giving up my machine yet again and, anyway, I was used to it so the warranty period expired.

About a month later Apple released a firmware update that fixed the blinking.

I know there are companies that might support their products after the warranty period and I know there are companies that stonewall but I thought this combination was pure Apple.

Completely ignore the problem for three years and then release an update after everyone is out of warranty anyway.

pmjordanOP14y ago

Wow, that is indeed classic Apple. Does the firmware update really fix it, though? My father-in-law has had all sorts of trouble with standby and his 2011 Mac Mini + Thunderbolt Display. Supposedly "fixed" by various firmware updates, but not much has changed.

aptwebapps14y ago

It seems to have worked.

paulmlewis14y ago

Interesting, I'd given up all hope of the flickering being fixed.

aptwebapps14y ago

To clarify, this is the problem where the screen blinks off really fast at completely random times. There's another problem with flickering that had something to do with scrolling.

j / k navigate · click thread line to collapse

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5 comments · 1 top-level

aptwebapps14y ago· 4 in thread

Going on a little (actually really long) tangent here about Apple and the general inscrutableness of their bug fixing ...

Well it didn't, to my utter lack of surprise, but I couldn't manage the hassle of giving up my machine yet again and, anyway, I was used to it so the warranty period expired.

About a month later Apple released a firmware update that fixed the blinking.

I know there are companies that might support their products after the warranty period and I know there are companies that stonewall but I thought this combination was pure Apple.

Completely ignore the problem for three years and then release an update after everyone is out of warranty anyway.

pmjordanOP14y ago

aptwebapps14y ago

It seems to have worked.

paulmlewis14y ago

Interesting, I'd given up all hope of the flickering being fixed.

aptwebapps14y ago

To clarify, this is the problem where the screen blinks off really fast at completely random times. There's another problem with flickering that had something to do with scrolling.

j / k navigate · click thread line to collapse