[PATCH] x86-64: Try multiple timer variants in check_timer

Instead of adding all kinds of more quirks try various timer
routing variants in check_timer.

In particular this tries to handle quirks from:
- Nvidia NF2-4 reference BIOS: wrong timer override
- Asus: Wrong timer override but no HPET table
- ATI: require timer disabled in 8259
- Some boards: require timer enabled in 8259

We just try many of the the known variants in the hopefully right order
in check_timer.

Trying pin 0/2 on Nvidia suggested by Tim Hockin.

TBD Experimental. Needs a lot of testing

Signed-off-by: Andi Kleen <ak@suse.de>

3 files changed, 51 insertions, 82 deletions

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index f3c57f43ba64..ab9b1c046c00 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -52,10 +52,6 @@ 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 68273bff58cc..fb0c6da41b7e 100644
--- a/arch/x86_64/kernel/early-quirks.c
+++ b/arch/x86_64/kernel/early-quirks.c
@@ -69,11 +69,6 @@ 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");
-        }
 }
 
 struct chipset {
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index f71461b1f03d..88fcc4ebbf6e 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -55,10 +55,6 @@ 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 };
 
@@ -348,29 +344,6 @@ 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-/* Actually the next is obsolete, but keep it for paranoid reasons -AK */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.
  */
@@ -1579,10 +1552,33 @@ 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 inline void check_timer(void)
+
+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)
 {
         int apic1, pin1, apic2, pin2;
         int vector;
@@ -1603,61 +1599,43 @@ static inline 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;
 
-        apic_printk(APIC_VERBOSE,KERN_INFO "..TIMER: vector=0x%02X apic1=%d pin1=%d apic2=%d pin2=%d\n",
-                vector, apic1, pin1, apic2, pin2);
+        /* Do this first, otherwise we get double interrupts on ATI boards */
+        if ((pin1 != -1) && try_apic_pin(apic1, pin1,"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");
-        }
+        /* 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);
 
-        apic_printk(APIC_VERBOSE,KERN_INFO "...trying to set up timer (IRQ0) "
-                                "through the 8259A ... ");
+        /* 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;
+
+        /* Then try pure 8259A routing on the 8259 as reported by BIOS*/
+        enable_8259A_irq(0);
         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 (timer_irq_works()) {
-                        apic_printk(APIC_VERBOSE," works.\n");
-                        nmi_watchdog_default();
-                        if (nmi_watchdog == NMI_IO_APIC) {
-                                setup_nmi();
-                        }
+                if (try_apic_pin(apic2,pin2,"8259A broadcast ExtINT from BIOS"))
                         return;
-                }
-                /*
-                 * Cleanup, just in case ...
-                 */
-                clear_IO_APIC_pin(apic2, pin2);
         }
-        apic_printk(APIC_VERBOSE," failed.\n");
+
+        /* Tried all possibilities to go through the IO-APIC. Now come the
+           really cheesy fallbacks. */
 
         if (nmi_watchdog == NMI_IO_APIC) {
                 printk(KERN_WARNING "timer doesn't work through the IO-APIC - disabling NMI Watchdog!\n");