x86: I/O APIC: timer through 8259A second-chance

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@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index 63a2f64..a69a59d 100644 (file)
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2122,6 +2122,7 @@ static inline void __init unlock_ExtINT_logic(void)
 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(void)
        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.
+        */
+       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(void)
                        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(void)
                 */
                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 --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index ae0ac99..9a54b77 100644 (file)
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -1638,6 +1638,7 @@ static inline void __init check_timer(void)
        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(void)
        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.
+        */
+       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(void)
                        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");
-       }
+               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 ... ");
-       if (pin2 != -1) {
+               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(void)
                 */
                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");