Hi,
Is it good / Bad / otherwise to turn on APIC when running QNX4.25 on PC hardware?
Many thanks for any enlightened viewpoints in advance…
It will work ok, but will in most cases, could disrupt real-time.
Thanks for that answer mario. I guess we just have to test hard to see that it is working ok. The reason I need to know is we have used up all free IRQs and it seems setting two devices with the same IRQ without APIC just causes a hard lockup.
(Network card IRQ 10, Multiport Serial on IRQ 5, and Graphics card on IRQ11). In order to use the new USB stack one requires some more free IRQ and the only way to get it to work is through APIC it seems!
Oh then you might not be getting what you are looking for QNX will not use the APIC. It will still be limited to the old interrupts scheme.
You might want to try to disable the Graphics card irq. I doubt that QNX is using it. It comes in handy during a video game if you want to switch image buffers just when the video gun is back at the top of the screen. Video cards are a mostly one direction peripheral you know.
Hi,
I tried to disable the Graphics card IRQ (it is a PCI graphics card) but it seemed the bios disregards that I disable it and automatically reassigns the IRQ (as confirmed by executing show_pci in QNX).
It is strange because everything seems to work ok as long as I have APIC enabled, otherwise i just get hard lockups…