arch/x86/kernel/apic/io_apic.c · ded1f6ab43a03be74a53649cf388b5424d447584 · nexedi / linux

x86: print APIC data a little later during boot · ded1f6ab
Naga Chumbalkar authored Jul 08, 2011
To view IOAPIC data you could boot with "apic=debug".

When booting in such a way then the kernel will dump the
IO-APIC's registers, for example:

NR Dst Mask Trig IRR Pol Stat Dmod Deli Vect:
 00 000 1    0    0   0   0    0    0    00
 01 000 0    0    0   0   0    0    0    31
 02 000 0    0    0   0   0    0    0    30
 03 000 0    0    0   0   0    0    0    33
 04 000 0    0    0   0   0    0    0    34
 05 000 0    0    0   0   0    0    0    35
 06 000 0    0    0   0   0    0    0    36
 07 000 0    0    0   0   0    0    0    37
 08 000 0    0    0   0   0    0    0    38
 09 000 0    1    0   0   0    0    0    39
 0a 000 0    0    0   0   0    0    0    3A
 0b 000 0    0    0   0   0    0    0    3B
 0c 000 0    0    0   0   0    0    0    3C
 0d 000 0    0    0   0   0    0    0    3D
 0e 000 0    0    0   0   0    0    0    3E
 0f 000 0    0    0   0   0    0    0    3F
 10 000 1    0    0   0   0    0    0    00
 11 000 1    0    0   0   0    0    0    00
 12 000 1    0    0   0   0    0    0    00
 13 000 1    0    0   0   0    0    0    00
 14 000 1    0    0   0   0    0    0    00
 15 000 1    0    0   0   0    0    0    00
 16 000 1    0    0   0   0    0    0    00
 17 000 1    0    0   0   0    0    0    00

Delaying the call to print_ICs() gives better results:

NR Dst Mask Trig IRR Pol Stat Dmod Deli Vect:
 00 000 1    0    0   0   0    0    0    00
 01 000 0    0    0   0   0    0    0    31
 02 000 0    0    0   0   0    0    0    30
 03 000 1    0    0   0   0    0    0    33
 04 000 1    0    0   0   0    0    0    34
 05 000 1    0    0   0   0    0    0    35
 06 000 1    0    0   0   0    0    0    36
 07 000 1    0    0   0   0    0    0    37
 08 000 0    0    0   0   0    0    0    38
 09 000 0    1    0   0   0    0    0    39
 0a 000 1    0    0   0   0    0    0    3A
 0b 000 1    0    0   0   0    0    0    3B
 0c 000 0    0    0   0   0    0    0    3C
 0d 000 1    0    0   0   0    0    0    3D
 0e 000 1    0    0   0   0    0    0    3E
 0f 000 1    0    0   0   0    0    0    3F
 10 000 1    1    0   1   0    0    0    29
 11 000 1    0    0   0   0    0    0    00
 12 000 1    0    0   0   0    0    0    00
 13 000 1    0    0   0   0    0    0    00
 14 000 0    1    0   1   0    0    0    51
 15 000 1    0    0   0   0    0    0    00
 16 000 0    1    0   1   0    0    0    61
 17 000 0    1    0   1   0    0    0    59

Notice that the entries beyond interrupt input signal 0x0f also
get populated and arent just the hw-initialization default of
all zeroes.
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Link: http://lkml.kernel.org/r/20110708083555.2598.42216.sendpatchset@nchumbalkar.americas.hpqcorp.netSigned-off-by: Ingo Molnar <mingo@elte.hu>
ded1f6ab
io_apic.c 96.9 KB
Replace io_apic.c
