increase irq 12 penalty
RFC PATCH 1/1 increase irq 12 penalty
This is something that Red Hat ships in its kernel. I was thinking it belonged upstream, but was told "Alan rejected it; reason forgotten" :)
Here is the logic for the patch:
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It makes the "pick any IRQ" code in the kernel not pick irq12 by default. irq12 is the ps/2 irq that gets emulated by smm on laptops. Using that can be sudden death on several machines.
So the patch makes the cost of using it higher than the other irq's.
Arjan, one of our RH kernel rpm maintainers, also adds:
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for all I know it's totally wrong
but it fixed some machines and it doesn't seem to break any
So I thought I would send it to lkml for comments. RH has been carrying this for a while...
kernel/pci-irq.c +1 -1
@@ -36,7 +36,7 @@ unsigned int pcibios_irq_mask = 0xfff8;static int pirq_penalty[16 ] = {1000000 ,1000000 ,1000000 ,1000 ,1000 ,0 ,1000 ,1000 , -0 ,0 ,0 ,0 ,1000 ,100000 ,100000 ,100000 +0 ,0 ,0 ,0 ,2500 ,100000 ,100000 ,100000 };struct irq_router {
[note, patch pathnames mangled to prevent immediate application :)]