[PATCH] 2.5.68 Fix IO_APIC IRQ assignment bug

Chuck Ebbert (76306.1226@compuserve.com)
Sun, 20 Apr 2003 18:06:51 -0400

Looks like the fix for the "ran out of interrupt sources" panic
has a problem. It will eventually assign a device the same IRQ
number as the first system vector, i.e. the local APIC timer.
I think this will fix it:

--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@ -1117,7 +1117,7 @
if (current_vector == SYSCALL_VECTOR)
goto next;

- if (current_vector > FIRST_SYSTEM_VECTOR) {
+ if (current_vector >= FIRST_SYSTEM_VECTOR) {
offset = (offset + 1) & 7;
current_vector = FIRST_DEVICE_VECTOR + offset;
}

I found this while trying to forward-port my .66 patch to make
the redirect table look like this:

NR Log Phy Mask Trig IRR Pol Stat Dest Deli Vect:
00 001 01 0 0 0 0 0 1 1 E7 <== timer at level E
01 001 01 0 0 0 0 0 1 1 30 <== start at 30, not 31
02 000 00 1 0 0 0 0 0 0 00
03 001 01 0 0 0 0 0 1 1 38
04 001 01 0 0 0 0 0 1 1 40
05 001 01 0 0 0 0 0 1 1 48
06 001 01 0 0 0 0 0 1 1 50
07 001 01 0 0 0 0 0 1 1 58
08 001 01 0 0 0 0 0 1 1 60
09 001 01 0 0 0 0 0 1 1 68
0a 001 01 0 0 0 0 0 1 1 70
0b 001 01 0 0 0 0 0 1 1 78
0c 001 01 0 0 0 0 0 1 1 88 <== only one device at 8
0d 001 01 0 0 0 0 0 1 1 90
0e 001 01 0 0 0 0 0 1 1 98
0f 000 00 1 0 0 0 0 0 0 00
10 001 01 1 1 0 1 0 1 1 A0
11 001 01 1 1 0 1 0 1 1 A8
12 001 01 1 1 0 1 0 1 1 B0
13 001 01 1 1 0 1 0 1 1 B8
14 001 01 0 0 0 0 0 1 1 C0
15 000 00 1 0 0 0 0 0 0 00
16 000 00 1 0 0 0 0 0 0 00
17 000 00 1 0 0 0 0 0 0 00

------
Chuck
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