[PATCH 8/8] x86: I/O APIC: Timer through 8259A second-chance
From: Maciej W. Rozycki
Date: Tue May 27 2008 - 16:21:54 EST
Some systems incorrectly report the ExtINTA pin of the I/O APIC as the
genuine target of the timer interrupt. Here is a change that copies timer
pin information found to the other pin if one has been found only. This
way both a direct and a through-8259A route is tested with the pin letting
these problematic systems work well enough. If no timer pin information
has been found for the I/O APIC, then local APIC variations are tried
only, similarly to what is done without the change (except without the
misleading messages).
Obviously if we try the first-chance path without being told by the BIOS
to do so, we should not complain either, so do not print the message in
this case.
The 64-bit variation should be updated with a call to
replace_pin_at_irq() which can be done with the upcoming merge. Since
add_pin_to_irq() is now always called in the first-chance path, the
condition to require it in the second-chance path no longer happens.
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxxxxx>
---
Ingo,
Despite looking quite innocent, this is the most intrusive modification
in the series. I tested this change (on top of all the other 14 ones)
with as many variations of interrupt wiring configuration as I could
imagine and simulate with my system. Of course my machine is perfectly
unbroken, :) so chances are more exotic convolutions may have escaped my
attention. Also I tested the 32-bit variation only. So again, I
recommend a good amount of testing in the field before this patch is
propagated upstream.
Maciej
patch-2.6.26-rc1-20080505-timer-pins-2
diff -up --recursive --new-file linux-2.6.26-rc1-20080505.macro/arch/x86/kernel/io_apic_32.c linux-2.6.26-rc1-20080505/arch/x86/kernel/io_apic_32.c
--- linux-2.6.26-rc1-20080505.macro/arch/x86/kernel/io_apic_32.c 2008-05-25 22:24:53.000000000 +0000
+++ linux-2.6.26-rc1-20080505/arch/x86/kernel/io_apic_32.c 2008-05-27 19:42:31.000000000 +0000
@@ -2122,6 +2122,7 @@ static inline void __init unlock_ExtINT_
static inline void __init check_timer(void)
{
int apic1, pin1, apic2, pin2;
+ int no_pin1 = 0;
int vector;
unsigned int ver;
unsigned long flags;
@@ -2159,10 +2160,30 @@ static inline void __init check_timer(vo
printk(KERN_INFO "..TIMER: vector=0x%02X apic1=%d pin1=%d apic2=%d pin2=%d\n",
vector, apic1, pin1, apic2, pin2);
+ /*
+ * Some BIOS writers are clueless and report the ExtINTA
+ * I/O APIC input from the cascaded 8259A as the timer
+ * interrupt input. So just in case, if only one pin
+ * was found above, try it both directly and through the
+ * 8259A. --macro
+ */
+ if (pin1 == -1) {
+ pin1 = pin2;
+ apic1 = apic2;
+ no_pin1 = 1;
+ } else if (pin2 == -1) {
+ pin2 = pin1;
+ apic2 = apic1;
+ }
+
if (pin1 != -1) {
/*
* Ok, does IRQ0 through the IOAPIC work?
*/
+ if (no_pin1) {
+ add_pin_to_irq(0, apic1, pin1);
+ setup_timer_IRQ0_pin(apic1, pin1, vector);
+ }
unmask_IO_APIC_irq(0);
if (timer_irq_works()) {
if (nmi_watchdog == NMI_IO_APIC) {
@@ -2174,26 +2195,23 @@ static inline void __init check_timer(vo
goto out;
}
clear_IO_APIC_pin(apic1, pin1);
- printk(KERN_ERR "..MP-BIOS bug: 8254 timer not connected to "
- "IO-APIC\n");
- }
+ if (!no_pin1)
+ printk(KERN_ERR "..MP-BIOS bug: "
+ "8254 timer not connected to IO-APIC\n");
- printk(KERN_INFO "...trying to set up timer (IRQ0) through the 8259A ... ");
- if (pin2 != -1) {
+ printk(KERN_INFO "...trying to set up timer (IRQ0) "
+ "through the 8259A ... ");
printk("\n..... (found pin %d) ...", pin2);
/*
* legacy devices should be connected to IO APIC #0
*/
+ replace_pin_at_irq(0, apic1, pin1, apic2, pin2);
setup_timer_IRQ0_pin(apic2, pin2, vector);
unmask_IO_APIC_irq(0);
enable_8259A_irq(0);
if (timer_irq_works()) {
printk("works.\n");
timer_through_8259 = 1;
- if (pin1 != -1)
- replace_pin_at_irq(0, apic1, pin1, apic2, pin2);
- else
- add_pin_to_irq(0, apic2, pin2);
if (nmi_watchdog == NMI_IO_APIC) {
disable_8259A_irq(0);
setup_nmi();
@@ -2206,8 +2224,8 @@ static inline void __init check_timer(vo
*/
disable_8259A_irq(0);
clear_IO_APIC_pin(apic2, pin2);
+ printk(" failed.\n");
}
- printk(" failed.\n");
if (nmi_watchdog == NMI_IO_APIC) {
printk(KERN_WARNING "timer doesn't work through the IO-APIC - disabling NMI Watchdog!\n");
diff -up --recursive --new-file linux-2.6.26-rc1-20080505.macro/arch/x86/kernel/io_apic_64.c linux-2.6.26-rc1-20080505/arch/x86/kernel/io_apic_64.c
--- linux-2.6.26-rc1-20080505.macro/arch/x86/kernel/io_apic_64.c 2008-05-25 22:26:43.000000000 +0000
+++ linux-2.6.26-rc1-20080505/arch/x86/kernel/io_apic_64.c 2008-05-27 19:44:19.000000000 +0000
@@ -1638,6 +1638,7 @@ static inline void __init check_timer(vo
struct irq_cfg *cfg = irq_cfg + 0;
int apic1, pin1, apic2, pin2;
unsigned long flags;
+ int no_pin1 = 0;
local_irq_save(flags);
@@ -1662,10 +1663,30 @@ static inline void __init check_timer(vo
apic_printk(APIC_VERBOSE,KERN_INFO "..TIMER: vector=0x%02X apic1=%d pin1=%d apic2=%d pin2=%d\n",
cfg->vector, apic1, pin1, apic2, pin2);
+ /*
+ * Some BIOS writers are clueless and report the ExtINTA
+ * I/O APIC input from the cascaded 8259A as the timer
+ * interrupt input. So just in case, if only one pin
+ * was found above, try it both directly and through the
+ * 8259A. --macro
+ */
+ if (pin1 == -1) {
+ pin1 = pin2;
+ apic1 = apic2;
+ no_pin1 = 1;
+ } else if (pin2 == -1) {
+ pin2 = pin1;
+ apic2 = apic1;
+ }
+
if (pin1 != -1) {
/*
* Ok, does IRQ0 through the IOAPIC work?
*/
+ if (no_pin1) {
+ add_pin_to_irq(0, apic1, pin1);
+ setup_timer_IRQ0_pin(apic1, pin1, vector);
+ }
unmask_IO_APIC_irq(0);
if (!no_timer_check && timer_irq_works()) {
nmi_watchdog_default();
@@ -1678,18 +1699,19 @@ static inline void __init check_timer(vo
goto out;
}
clear_IO_APIC_pin(apic1, pin1);
- apic_printk(APIC_QUIET,KERN_ERR "..MP-BIOS bug: 8254 timer not "
- "connected to IO-APIC\n");
- }
-
- apic_printk(APIC_VERBOSE,KERN_INFO "...trying to set up timer (IRQ0) "
- "through the 8259A ... ");
- if (pin2 != -1) {
+ if (!no_pin1)
+ apic_printk(APIC_QUIET,KERN_ERR "..MP-BIOS bug: "
+ "8254 timer not connected to IO-APIC\n");
+
+ apic_printk(APIC_VERBOSE,KERN_INFO
+ "...trying to set up timer (IRQ0) "
+ "through the 8259A ... ");
apic_printk(APIC_VERBOSE,"\n..... (found apic %d pin %d) ...",
apic2, pin2);
/*
* legacy devices should be connected to IO APIC #0
*/
+ /* replace_pin_at_irq(0, apic1, pin1, apic2, pin2); */
setup_timer_IRQ0_pin(apic2, pin2, cfg->vector);
unmask_IO_APIC_irq(0);
enable_8259A_irq(0);
@@ -1709,8 +1731,8 @@ static inline void __init check_timer(vo
*/
disable_8259A_irq(0);
clear_IO_APIC_pin(apic2, pin2);
+ apic_printk(APIC_VERBOSE," failed.\n");
}
- apic_printk(APIC_VERBOSE," failed.\n");
if (nmi_watchdog == NMI_IO_APIC) {
printk(KERN_WARNING "timer doesn't work through the IO-APIC - disabling NMI Watchdog!\n");
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/