Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e585bef815c0315f2730d7bb4e15b82602454efd
Commit:     e585bef815c0315f2730d7bb4e15b82602454efd
Parent:     296d93cd0205433489b0689533426ce0a8cf2dec
Author:     Thomas Gleixner <[EMAIL PROTECTED]>
AuthorDate: Fri Mar 23 16:08:01 2007 +0100
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Fri Mar 23 10:21:02 2007 -0700

    [PATCH] i386: add command line option "local_apic_timer_c2_ok"
    
    It turned out that it is almost impossible to trust ACPI, BIOS & Co.
    regarding the C states. This was the reason to switch the local apic
    timer off in C2 state already. OTOH there are sane and well behaving
    systems, which get punished by that decision.
    
    Allow the user to confirm that the local apic timer is trustworthy in C2
    state. This keeps the default behaviour on the safe side.
    
    Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
    Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 Documentation/kernel-parameters.txt |    3 +++
 arch/i386/kernel/apic.c             |   10 ++++++++++
 drivers/acpi/processor_idle.c       |    3 ++-
 include/asm-i386/apic.h             |    1 +
 4 files changed, 16 insertions(+), 1 deletions(-)

diff --git a/Documentation/kernel-parameters.txt 
b/Documentation/kernel-parameters.txt
index e39ab0c..09640a8 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -780,6 +780,9 @@ and is between 256 and 4096 characters. It is defined in 
the file
        lapic           [IA-32,APIC] Enable the local APIC even if BIOS
                        disabled it.
 
+       lapic_timer_c2_ok       [IA-32,APIC] trust the local apic timer in
+                       C2 power state.
+
        lasi=           [HW,SCSI] PARISC LASI driver for the 53c700 chip
                        Format: addr:<io>,irq:<irq>
 
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 244c3fe..e884152 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -64,6 +64,9 @@ static int enable_local_apic __initdata = 0;
 static int local_apic_timer_verify_ok;
 /* Disable local APIC timer from the kernel commandline or via dmi quirk */
 static int local_apic_timer_disabled;
+/* Local APIC timer works in C2 */
+int local_apic_timer_c2_ok;
+EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
 
 /*
  * Debug level, exported for io_apic.c
@@ -1232,6 +1235,13 @@ static int __init parse_disable_lapic_timer(char *arg)
 }
 early_param("nolapic_timer", parse_disable_lapic_timer);
 
+static int __init parse_lapic_timer_c2_ok(char *arg)
+{
+       local_apic_timer_c2_ok = 1;
+       return 0;
+}
+early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok);
+
 static int __init apic_set_verbosity(char *str)
 {
        if (strcmp("debug", str) == 0)
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 6077300..cdf7894 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -268,6 +268,7 @@ static void acpi_timer_check_state(int state, struct 
acpi_processor *pr,
                                   struct acpi_processor_cx *cx)
 {
        struct acpi_processor_power *pwr = &pr->power;
+       u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 
        /*
         * Check, if one of the previous states already marked the lapic
@@ -276,7 +277,7 @@ static void acpi_timer_check_state(int state, struct 
acpi_processor *pr,
        if (pwr->timer_broadcast_on_state < state)
                return;
 
-       if (cx->type >= ACPI_STATE_C2)
+       if (cx->type >= type)
                pr->power.timer_broadcast_on_state = state;
 }
 
diff --git a/include/asm-i386/apic.h b/include/asm-i386/apic.h
index cc6b165..a19810a 100644
--- a/include/asm-i386/apic.h
+++ b/include/asm-i386/apic.h
@@ -117,6 +117,7 @@ extern void enable_NMI_through_LVT0 (void * dummy);
 #define ARCH_APICTIMER_STOPS_ON_C3     1
 
 extern int timer_over_8254;
+extern int local_apic_timer_c2_ok;
 
 #else /* !CONFIG_X86_LOCAL_APIC */
 static inline void lapic_shutdown(void) { }
-
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to