4 ms·

I've always had the attitude that if can reproduce a bug consistently, I can debug it, and I can fix it. Now here's a nail in the coffin of that theory.

aidenn0 7y ago
A rule of thumb I use is that if I can reproduce a bug in approximately 0 time, I can fix it within 1 hour 95% of the time.
masswerk 7y ago
In defense of the coffin, I'd say this is not so much about a bug, but about reverse engineering real world effects of undefined behavior (as caused by a bug in software).
- deleted 7y ago
  [deleted]
- aidenn0 7y ago
  If the goal of mgba is to reproduce the GBA hardware faithfully, then this is a pure software bug in mgba.
  - NieDzejkob 7y ago
    You are trying to argue about the meaning of the words being used. This is not productive, as what matters is what the author of the argument meant when they used that word.
    - aidenn0 7y ago
      I don't think that's the case. When talking about emulation and virtualization and such, it is easy to get terms backwards. For example, a bug in the implementation of a virtualized device looks like a hardware bug to the client and like a software bug to the host.
      - masswerk 7y ago
        To be honest, I think it's about crossing the lines of emulation and simulation. In emulation, we mostly consider instruction level behavior as good enough, but here, we'll have to venture below cycle level and integrated hardware effects to copy the behavior.
  - pingyong 7y ago
    That is not the goal of mGBA (or any GBA emulator for that matter), btw. If you wanted to reproduce it faithfully, the emulator would be unusably slow. https://emulation.gametechwiki.com/index.php/Emulation_Accuracy https://emulation.gametechwiki.com/index.php/Emulation_Accur...
    - aidenn0 7y ago
      s/faithfully/faithfully enough/ Prior to the bug being fixed this was clearly not faithfully enough for at least 2 games.
rgoulter 7y ago
Most of the bugs I've dealt with, the problem was usually down to something simple that can be explained quickly. (e.g. syntactically valid typo, config error, simple logic error etc.). Seems like "Holy grail" bugs like this happen to need a thorough understanding of complex systems (which I usually like to hide under layers of abstraction).
umvi 7y ago
Only if the problem is purely software. I've had reproducible problems that were impossible to solve by myself. The process went like this: - Huh, getting USB disconnects randomly, need to fix this - Hmm, device driver seems to be fine - Hmm usbnet driver seems fine - Hmm xhci driver seem fine - $5000 and one USB 3.0 protocol analyzer later... - What the heck is this host controller doing? At this point it was looking like a hardware problem but seeing as I didn't have the schematics or verilog of the host controller I could go no further (nor did I want too... I never imagined USB could be such a deep rabbit hole).

aidenn0 7y ago

A rule of thumb I use is that if I can reproduce a bug in approximately 0 time, I can fix it within 1 hour 95% of the time.

masswerk 7y ago

In defense of the coffin, I'd say this is not so much about a bug, but about reverse engineering real world effects of undefined behavior (as caused by a bug in software).

deleted 7y ago
[deleted]
aidenn0 7y ago
If the goal of mgba is to reproduce the GBA hardware faithfully, then this is a pure software bug in mgba.
- NieDzejkob 7y ago
  You are trying to argue about the meaning of the words being used. This is not productive, as what matters is what the author of the argument meant when they used that word.
  - aidenn0 7y ago
    I don't think that's the case. When talking about emulation and virtualization and such, it is easy to get terms backwards. For example, a bug in the implementation of a virtualized device looks like a hardware bug to the client and like a software bug to the host.
    - masswerk 7y ago
      To be honest, I think it's about crossing the lines of emulation and simulation. In emulation, we mostly consider instruction level behavior as good enough, but here, we'll have to venture below cycle level and integrated hardware effects to copy the behavior.
- pingyong 7y ago
  That is not the goal of mGBA (or any GBA emulator for that matter), btw. If you wanted to reproduce it faithfully, the emulator would be unusably slow. https://emulation.gametechwiki.com/index.php/Emulation_Accuracy https://emulation.gametechwiki.com/index.php/Emulation_Accur...
  - aidenn0 7y ago
    s/faithfully/faithfully enough/ Prior to the bug being fixed this was clearly not faithfully enough for at least 2 games.

rgoulter 7y ago

Most of the bugs I've dealt with, the problem was usually down to something simple that can be explained quickly. (e.g. syntactically valid typo, config error, simple logic error etc.). Seems like "Holy grail" bugs like this happen to need a thorough understanding of complex systems (which I usually like to hide under layers of abstraction).

umvi 7y ago

Only if the problem is purely software. I've had reproducible problems that were impossible to solve by myself. The process went like this: - Huh, getting USB disconnects randomly, need to fix this - Hmm, device driver seems to be fine - Hmm usbnet driver seems fine - Hmm xhci driver seem fine - $5000 and one USB 3.0 protocol analyzer later... - What the heck is this host controller doing? At this point it was looking like a hardware problem but seeing as I didn't have the schematics or verilog of the host controller I could go no further (nor did I want too... I never imagined USB could be such a deep rabbit hole).