[PATCH] x86-64: i386/x86-64: Fix time going twice as fast problem on ATI Xpress chipsets

Original patch from Bertro Simul

This is probably still not quite correct, but seems to be
the best solution so far.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Documentation/kernel-parameters.txt

@@ -164,6 +164,15 @@ running once the system is up.
 			over-ride platform specific driver.
 			See also Documentation/acpi-hotkey.txt.
 
+	enable_timer_pin_1 [i386,x86-64]
+			Enable PIN 1 of APIC timer
+			Can be useful to work around chipset bugs (in particular on some ATI chipsets)
+			The kernel tries to set a reasonable default.
+
+	disable_timer_pin_1 [i386,x86-64]
+			Disable PIN 1 of APIC timer
+			Can be useful to work around chipset bugs.
+
 	ad1816=		[HW,OSS]
 			Format: <io>,<irq>,<dma>,<dma2>
 			See also Documentation/sound/oss/AD1816.

arch/i386/kernel/acpi/earlyquirk.c

@@ -15,6 +15,13 @@ static int __init check_bridge(int vendor, int device)
 	if (vendor == PCI_VENDOR_ID_NVIDIA) {
 		acpi_skip_timer_override = 1;
 	}
+	/*
+	 * ATI IXP chipsets get double timer interrupts.
+	 * For now just do this for all ATI chipsets.
+ 	 * FIXME: this needs to be checked for the non ACPI case too.
+	 */
+	if (vendor == PCI_VENDOR_ID_ATI)
+		disable_timer_pin_1 = 1;
 	return 0;
 }
 

arch/i386/kernel/io_apic.c

@@ -60,6 +60,8 @@ int sis_apic_bug = -1;
  */
 int nr_ioapic_registers[MAX_IO_APICS];
 
+int disable_timer_pin_1 __initdata;
+
 /*
  * Rough estimation of how many shared IRQs there are, can
  * be changed anytime.
@@ -2211,6 +2213,8 @@ static inline void check_timer(void)
 				setup_nmi();
 				enable_8259A_irq(0);
 			}
+			if (disable_timer_pin_1 > 0)
+				clear_IO_APIC_pin(0, pin1);
 			return;
 		}
 		clear_IO_APIC_pin(0, pin1);

arch/i386/kernel/setup.c

@@ -851,6 +851,11 @@ static void __init parse_cmdline_early (char ** cmdline_p)
 #endif
 
 #ifdef CONFIG_X86_LOCAL_APIC
+		if (!memcmp(from, "disable_timer_pin_1", 19))
+			disable_timer_pin_1 = 1;
+		if (!memcmp(from, "enable_timer_pin_1", 18))
+			disable_timer_pin_1 = -1;
+
 		/* disable IO-APIC */
 		else if (!memcmp(from, "noapic", 6))
 			disable_ioapic_setup();

arch/x86_64/kernel/io_apic.c

@@ -44,6 +44,8 @@ int sis_apic_bug; /* not actually supported, dummy for compile */
 
 static int no_timer_check;
 
+int disable_timer_pin_1 __initdata;
+
 static DEFINE_SPINLOCK(ioapic_lock);
 
 /*
@@ -297,6 +299,15 @@ void __init check_ioapic(void)
 #endif
 					/* RED-PEN skip them on mptables too? */
 					return;
+				case PCI_VENDOR_ID_ATI:
+					/* All timer interrupts on atiixp
+				           are doubled. Disable one. */
+					if (disable_timer_pin_1 == 0) {
+						disable_timer_pin_1 = 1;
+						printk(KERN_INFO
+		"ATI board detected. Disabling timer pin 1.\n");
+					}
+					return;
 				} 
 
 				/* No multi-function device? */
@@ -1658,6 +1669,8 @@ static inline void check_timer(void)
 				setup_nmi();
 				enable_8259A_irq(0);
 			}
+			if (disable_timer_pin_1 > 0)
+				clear_IO_APIC_pin(0, pin1);
 			return;
 		}
 		clear_IO_APIC_pin(0, pin1);

arch/x86_64/kernel/setup.c

@@ -336,6 +336,11 @@ static __init void parse_cmdline_early (char ** cmdline_p)
 #endif
 #endif
 
+		if (!memcmp(from, "disable_timer_pin_1", 19))
+			disable_timer_pin_1 = 1;
+		if (!memcmp(from, "enable_timer_pin_1", 18))
+			disable_timer_pin_1 = -1;
+
 		if (!memcmp(from, "nolapic", 7) ||
 		    !memcmp(from, "disableapic", 11))
 			disable_apic = 1;

include/asm-i386/apic.h

@@ -130,6 +130,8 @@ extern unsigned int nmi_watchdog;
 #define NMI_LOCAL_APIC	2
 #define NMI_INVALID	3
 
+extern int disable_timer_pin_1;
+
 #else /* !CONFIG_X86_LOCAL_APIC */
 static inline void lapic_shutdown(void) { }
 

include/asm-x86_64/apic.h

@@ -109,6 +109,8 @@ extern unsigned int nmi_watchdog;
 #define NMI_LOCAL_APIC	2
 #define NMI_INVALID	3
 
+extern int disable_timer_pin_1;
+
 #endif /* CONFIG_X86_LOCAL_APIC */
 
 extern unsigned boot_cpu_id;