[PATCH] x86: Add acpi_user_timer_override option for Asus boards

Timer overrides are normally disabled on Nvidia board because
they are commonly wrong, except on new ones with HPET support.
Unfortunately there are quite some Asus boards around that
don't have HPET, but need a timer override.

We don't know yet how to handle this transparently,
but at least add a command line option to force the timer override
and let them boot.

Cc: len.brown@intel.com

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

6 files changed, 29 insertions, 1 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index dd00fd556a60..67473849f20e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -164,6 +164,10 @@ and is between 256 and 4096 characters. It is defined in the file
         acpi_skip_timer_override [HW,ACPI]
                         Recognize and ignore IRQ0/pin2 Interrupt Override.
                         For broken nForce2 BIOS resulting in XT-PIC timer.
+        acpi_use_timer_override [HW,ACPI}
+                        Use timer override. For some broken Nvidia NF5 boards
+                        that require a timer override, but don't have
+                        HPET
 
         acpi_dbg_layer= [HW,ACPI]
                         Format: <int>
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index 22e4c466e5a3..d12fb97a5337 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -82,6 +82,7 @@ EXPORT_SYMBOL(acpi_strict);
 acpi_interrupt_flags acpi_sci_flags __initdata;
 int acpi_sci_override_gsi __initdata;
 int acpi_skip_timer_override __initdata;
+int acpi_use_timer_override __initdata;
 
 #ifdef CONFIG_X86_LOCAL_APIC
 static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
@@ -1300,6 +1301,13 @@ static int __init parse_acpi_skip_timer_override(char *arg)
         return 0;
 }
 early_param("acpi_skip_timer_override", parse_acpi_skip_timer_override);
+
+static int __init parse_acpi_use_timer_override(char *arg)
+{
+        acpi_use_timer_override = 1;
+        return 0;
+}
+early_param("acpi_use_timer_override", parse_acpi_use_timer_override);
 #endif /* CONFIG_X86_IO_APIC */
 
 static int __init setup_acpi_sci(char *s)
diff --git a/arch/i386/kernel/acpi/earlyquirk.c b/arch/i386/kernel/acpi/earlyquirk.c
index fe799b11ac0a..c9841692bb7c 100644
--- a/arch/i386/kernel/acpi/earlyquirk.c
+++ b/arch/i386/kernel/acpi/earlyquirk.c
@@ -27,11 +27,17 @@ static int __init check_bridge(int vendor, int device)
 #ifdef CONFIG_ACPI
         /* According to Nvidia all timer overrides are bogus unless HPET
            is enabled. */
-        if (vendor == PCI_VENDOR_ID_NVIDIA) {
+        if (!acpi_use_timer_override && vendor == PCI_VENDOR_ID_NVIDIA) {
                 nvidia_hpet_detected = 0;
                 acpi_table_parse(ACPI_HPET, nvidia_hpet_check);
                 if (nvidia_hpet_detected == 0) {
                         acpi_skip_timer_override = 1;
+                          printk(KERN_INFO "Nvidia board "
+                       "detected. Ignoring ACPI "
+                       "timer override.\n");
+                printk(KERN_INFO "If you got timer trouble "
+                                 "try acpi_use_timer_override\n");
+
                 }
         }
 #endif
diff --git a/arch/x86_64/kernel/early-quirks.c b/arch/x86_64/kernel/early-quirks.c
index 2b1245d86258..68273bff58cc 100644
--- a/arch/x86_64/kernel/early-quirks.c
+++ b/arch/x86_64/kernel/early-quirks.c
@@ -45,7 +45,13 @@ static void nvidia_bugs(void)
         /*
          * All timer overrides on Nvidia are
          * wrong unless HPET is enabled.
+         * Unfortunately that's not true on many Asus boards.
+         * We don't know yet how to detect this automatically, but
+         * at least allow a command line override.
          */
+        if (acpi_use_timer_override)
+                return;
+
         nvidia_hpet_detected = 0;
         acpi_table_parse(ACPI_HPET, nvidia_hpet_check);
         if (nvidia_hpet_detected == 0) {
@@ -53,6 +59,8 @@ static void nvidia_bugs(void)
                 printk(KERN_INFO "Nvidia board "
                        "detected. Ignoring ACPI "
                        "timer override.\n");
+                printk(KERN_INFO "If you got timer trouble "
+                        "try acpi_use_timer_override\n");
         }
 #endif
         /* RED-PEN skip them on mptables too? */
diff --git a/include/asm-i386/acpi.h b/include/asm-i386/acpi.h
index 6016632d032f..c80b3a94511a 100644
--- a/include/asm-i386/acpi.h
+++ b/include/asm-i386/acpi.h
@@ -132,6 +132,7 @@ extern int acpi_gsi_to_irq(u32 gsi, unsigned int *irq);
 
 #ifdef CONFIG_X86_IO_APIC
 extern int acpi_skip_timer_override;
+extern int acpi_use_timer_override;
 #endif
 
 static inline void acpi_noirq_set(void) { acpi_noirq = 1; }
diff --git a/include/asm-x86_64/acpi.h b/include/asm-x86_64/acpi.h
index ed59aa4c6ff9..9d1916e59c04 100644
--- a/include/asm-x86_64/acpi.h
+++ b/include/asm-x86_64/acpi.h
@@ -163,6 +163,7 @@ extern u8 x86_acpiid_to_apicid[];
 #define ARCH_HAS_POWER_INIT 1
 
 extern int acpi_skip_timer_override;
+extern int acpi_use_timer_override;
 
 #endif /*__KERNEL__*/