linux-kernel - [PATCH]: x86: print APIC data a little later during boot

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Message-Id: <20110708083555.2598.42216.sendpatchset@nchumbalkar.americas.hpqcorp.net>
Date:	Fri,  8 Jul 2011 08:36:34 +0000 (UTC)
From:	Naga Chumbalkar <nagananda.chumbalkar@...com>
To:	x86@...nel.org
Cc:	Naga Chumbalkar <nagananda.chumbalkar@...com>, mingo@...e.hu,
	tglx@...utronix.de, linux-kernel@...r.kernel.org, hpa@...or.com
Subject: [PATCH]: x86: print APIC data a little later during boot

To view IOAPIC data you could boot with "apic=debug".
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 APIC data 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.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@...com>

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index e529339..98c8d7e 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1792,7 +1792,7 @@ __apicdebuginit(int) print_ICs(void)
 	return 0;
 }
 
-fs_initcall(print_ICs);
+late_initcall(print_ICs);
 
 
 /* Where if anywhere is the i8259 connect in external int mode */
--
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