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authorNick Piggin <nickpiggin@yahoo.com.au>2005-12-02 12:44:19 +1100
committerLinus Torvalds <torvalds@g5.osdl.org>2005-12-02 14:20:21 -0800
commit2a298a35ebe060a6f2b06b20c2a34ea188ddfd37 (patch)
tree226dd2569d657231a3c24d8228467a039ffc6681
parentdeda498710e190c7922c2634ed630ee64ce86c05 (diff)
[PATCH] Fix TIF_POLLING_NRFLAG in ACPI idle routines
Commit 64c7c8f88559624abdbe12b5da6502e8879f8d28 broke the ACPI C2 and C3 sleep states, because it left TIF_POLLING_NRFLAG active even though those states do not actually poll the reschedule flag at all. As a result, the CPU wouldn't get sent an IPI when it was to be woken up, and would only notice that it had runnable processes on the next timer tick. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--drivers/acpi/processor_idle.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 83fd1b6c10c4..acd875e0caca 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -169,15 +169,11 @@ acpi_processor_power_activate(struct acpi_processor *pr,
static void acpi_safe_halt(void)
{
- int polling = test_thread_flag(TIF_POLLING_NRFLAG);
- if (polling) {
- clear_thread_flag(TIF_POLLING_NRFLAG);
- smp_mb__after_clear_bit();
- }
+ clear_thread_flag(TIF_POLLING_NRFLAG);
+ smp_mb__after_clear_bit();
if (!need_resched())
safe_halt();
- if (polling)
- set_thread_flag(TIF_POLLING_NRFLAG);
+ set_thread_flag(TIF_POLLING_NRFLAG);
}
static atomic_t c3_cpu_count;
@@ -295,6 +291,15 @@ static void acpi_processor_idle(void)
* ------
* Invoke the current Cx state to put the processor to sleep.
*/
+ if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
+ clear_thread_flag(TIF_POLLING_NRFLAG);
+ smp_mb__after_clear_bit();
+ if (need_resched()) {
+ set_thread_flag(TIF_POLLING_NRFLAG);
+ return;
+ }
+ }
+
switch (cx->type) {
case ACPI_STATE_C1:
@@ -327,6 +332,7 @@ static void acpi_processor_idle(void)
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
/* Re-enable interrupts */
local_irq_enable();
+ set_thread_flag(TIF_POLLING_NRFLAG);
/* Compute time (ticks) that we were actually asleep */
sleep_ticks =
ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
@@ -366,6 +372,7 @@ static void acpi_processor_idle(void)
/* Re-enable interrupts */
local_irq_enable();
+ set_thread_flag(TIF_POLLING_NRFLAG);
/* Compute time (ticks) that we were actually asleep */
sleep_ticks =
ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;