PS/2 IRQ not firing + spurious IRQ (real hardware)

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Magyar57
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Re: PS/2 IRQ not firing + spurious IRQ (real hardware)

Post by Magyar57 »

I was thinking of the APIC implementation, and then I thought: isn't the i8259 PIC on the CPU die on modern processors (just like the APIC) ?
If it's the case, how could there be a bug in the PIC ? Intel/ADM would reuse their old design for this part of the dies, and that's it (so old circuitry which is well tested, no bug in sight)...
Octocontrabass
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Re: PS/2 IRQ not firing + spurious IRQ (real hardware)

Post by Octocontrabass »

Magyar57 wrote: Tue Mar 25, 2025 5:58 pmisn't the i8259 PIC on the CPU die on modern processors (just like the APIC) ?
It might be. You can try checking your CPU's datasheet.
Magyar57 wrote: Tue Mar 25, 2025 5:58 pmIf it's the case, how could there be a bug in the PIC ?
Who would notice a bug in the PIC? Modern OSes don't use it, they have APIC.
Magyar57
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Re: PS/2 IRQ not firing + spurious IRQ (real hardware)

Post by Magyar57 »

Octocontrabass wrote: Tue Mar 25, 2025 6:31 pm It might be. You can try checking your CPU's datasheet.
I've tried numerous times, but every time I just end up with the poor Intel or AMD marketing pdf with stuff like number of cores, frequency and that's it. Do you know where to find it ? (say, for the r7 7840hs)
Octocontrabass wrote: Tue Mar 25, 2025 6:31 pm Who would notice a bug in the PIC? Modern OSes don't use it, they have APIC.
What I meant is, it has been well used and tested back in the days, and now since it's not used anymore (but for backward compatibility), they have no reasons to change the circuit and therefore introduce bugs: "if it works, don't touch it" :)
nullplan
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Re: PS/2 IRQ not firing + spurious IRQ (real hardware)

Post by nullplan »

Magyar57 wrote: Wed Mar 26, 2025 4:47 am What I meant is, it has been well used and tested back in the days, and now since it's not used anymore (but for backward compatibility), they have no reasons to change the circuit and therefore introduce bugs: "if it works, don't touch it" :)
Possibly, but the system design might have introduced a regression somewhere, or maybe the thing is wired up wrong internally, and that wouldn't be noticed.
Carpe diem!
Octocontrabass
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Re: PS/2 IRQ not firing + spurious IRQ (real hardware)

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