3 files changed, 82 insertions, 51 deletions

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index dbdcaf68e3ea..5c86ed6f0448 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -52,6 +52,10 @@ APICs
                  apicmaintimer. Useful when your PIT timer is totally
                  broken.
 
+   disable_8254_timer / enable_8254_timer
+                 Enable interrupt 0 timer routing over the 8254 in addition to over
+                 the IO-APIC. The kernel tries to set a sensible default.
+
 Early Console
 
    syntax: earlyprintk=vga
diff --git a/arch/x86_64/kernel/early-quirks.c b/arch/x86_64/kernel/early-quirks.c
index 829698f6d049..49802f1bee94 100644
--- a/arch/x86_64/kernel/early-quirks.c
+++ b/arch/x86_64/kernel/early-quirks.c
@@ -69,6 +69,11 @@ static void nvidia_bugs(void)
 
 static void ati_bugs(void)
 {
+        if (timer_over_8254 == 1) {
+                timer_over_8254 = 0;
+                printk(KERN_INFO
+                "ATI board detected. Disabling timer routing over 8254.\n");
+        }
 }
 
 static void intel_bugs(void)
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index 2a1dcd5f69c2..d7bad90a5ad8 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -55,6 +55,10 @@ int sis_apic_bug; /* not actually supported, dummy for compile */
 
 static int no_timer_check;
 
+static int disable_timer_pin_1 __initdata;
+
+int timer_over_8254 __initdata = 1;
+
 /* Where if anywhere is the i8259 connect in external int mode */
 static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };
 
@@ -350,6 +354,29 @@ static int __init disable_ioapic_setup(char *str)
 }
 early_param("noapic", disable_ioapic_setup);
 
+/* Actually the next is obsolete, but keep it for paranoid reasons -AK */
+static int __init disable_timer_pin_setup(char *arg)
+{
+        disable_timer_pin_1 = 1;
+        return 1;
+}
+__setup("disable_timer_pin_1", disable_timer_pin_setup);
+
+static int __init setup_disable_8254_timer(char *s)
+{
+        timer_over_8254 = -1;
+        return 1;
+}
+static int __init setup_enable_8254_timer(char *s)
+{
+        timer_over_8254 = 2;
+        return 1;
+}
+
+__setup("disable_8254_timer", setup_disable_8254_timer);
+__setup("enable_8254_timer", setup_enable_8254_timer);
+
+
 /*
  * Find the IRQ entry number of a certain pin.
  */
@@ -1568,33 +1595,10 @@ static inline void unlock_ExtINT_logic(void)
  * a wide range of boards and BIOS bugs.  Fortunately only the timer IRQ
  * is so screwy.  Thanks to Brian Perkins for testing/hacking this beast
  * fanatically on his truly buggy board.
+ *
+ * FIXME: really need to revamp this for modern platforms only.
  */
-
-static int try_apic_pin(int apic, int pin, char *msg)
-{
-        apic_printk(APIC_VERBOSE, KERN_INFO
-                    "..TIMER: trying IO-APIC=%d PIN=%d %s",
-                    apic, pin, msg);
-
-        /*
-         * Ok, does IRQ0 through the IOAPIC work?
-         */
-        if (!no_timer_check && timer_irq_works()) {
-                nmi_watchdog_default();
-                if (nmi_watchdog == NMI_IO_APIC) {
-                        disable_8259A_irq(0);
-                        setup_nmi();
-                        enable_8259A_irq(0);
-                }
-                return 1;
-        }
-        clear_IO_APIC_pin(apic, pin);
-        apic_printk(APIC_QUIET, KERN_ERR " .. failed\n");
-        return 0;
-}
-
-/* The function from hell */
-static void check_timer(void)
+static inline void check_timer(void)
 {
         int apic1, pin1, apic2, pin2;
         int vector;
@@ -1615,43 +1619,61 @@ static void check_timer(void)
          */
         apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);
         init_8259A(1);
+        if (timer_over_8254 > 0)
+                enable_8259A_irq(0);
 
         pin1  = find_isa_irq_pin(0, mp_INT);
         apic1 = find_isa_irq_apic(0, mp_INT);
         pin2  = ioapic_i8259.pin;
         apic2 = ioapic_i8259.apic;
 
-        /* Do this first, otherwise we get double interrupts on ATI boards */
-        if ((pin1 != -1) && try_apic_pin(apic1, pin1,"with 8259 IRQ0 disabled"))
-                return;
+        apic_printk(APIC_VERBOSE,KERN_INFO "..TIMER: vector=0x%02X apic1=%d pin1=%d apic2=%d pin2=%d\n",
+                vector, apic1, pin1, apic2, pin2);
 
-        /* Now try again with IRQ0 8259A enabled.
-           Assumes timer is on IO-APIC 0 ?!? */
-        enable_8259A_irq(0);
-        unmask_IO_APIC_irq(0);
-        if (try_apic_pin(apic1, pin1, "with 8259 IRQ0 enabled"))
-                return;
-        disable_8259A_irq(0);
-
-        /* Always try pin0 and pin2 on APIC 0 to handle buggy timer overrides
-           on Nvidia boards */
-        if (!(apic1 == 0 && pin1 == 0) &&
-            try_apic_pin(0, 0, "fallback with 8259 IRQ0 disabled"))
-                return;
-        if (!(apic1 == 0 && pin1 == 2) &&
-            try_apic_pin(0, 2, "fallback with 8259 IRQ0 disabled"))
-                return;
+        if (pin1 != -1) {
+                /*
+                 * Ok, does IRQ0 through the IOAPIC work?
+                 */
+                unmask_IO_APIC_irq(0);
+                if (!no_timer_check && timer_irq_works()) {
+                        nmi_watchdog_default();
+                        if (nmi_watchdog == NMI_IO_APIC) {
+                                disable_8259A_irq(0);
+                                setup_nmi();
+                                enable_8259A_irq(0);
+                        }
+                        if (disable_timer_pin_1 > 0)
+                                clear_IO_APIC_pin(0, pin1);
+                        return;
+                }
+                clear_IO_APIC_pin(apic1, pin1);
+                apic_printk(APIC_QUIET,KERN_ERR "..MP-BIOS bug: 8254 timer not "
+                                "connected to IO-APIC\n");
+        }
 
-        /* Then try pure 8259A routing on the 8259 as reported by BIOS*/
-        enable_8259A_irq(0);
+        apic_printk(APIC_VERBOSE,KERN_INFO "...trying to set up timer (IRQ0) "
+                                "through the 8259A ... ");
         if (pin2 != -1) {
+                apic_printk(APIC_VERBOSE,"\n..... (found apic %d pin %d) ...",
+                        apic2, pin2);
+                /*
+                 * legacy devices should be connected to IO APIC #0
+                 */
                 setup_ExtINT_IRQ0_pin(apic2, pin2, vector);
-                if (try_apic_pin(apic2,pin2,"8259A broadcast ExtINT from BIOS"))
+                if (timer_irq_works()) {
+                        apic_printk(APIC_VERBOSE," works.\n");
+                        nmi_watchdog_default();
+                        if (nmi_watchdog == NMI_IO_APIC) {
+                                setup_nmi();
+                        }
                         return;
+                }
+                /*
+                 * Cleanup, just in case ...
+                 */
+                clear_IO_APIC_pin(apic2, pin2);
         }
-
-        /* Tried all possibilities to go through the IO-APIC. Now come the
-           really cheesy fallbacks. */
+        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");