ACPI processor: force throttling state when BIOS returns incorrect value
If the BIOS reports an invalid throttling state (which seems to be
fairly common after system boot), a reset is done to state T0.
Because of a check in acpi_processor_get_throttling_ptc(), the reset
never actually gets executed, which results in the error reoccurring
on every access of for example /proc/acpi/processor/CPU0/throttling.
Add a 'force' option to acpi_processor_set_throttling() to ensure
the reset really takes effect.
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13389
This patch, together with the next one, fixes a regression introduced in
2.6.30, listed on the regression list. They have been available for 2.5
months now in bugzilla, but have not been picked up, despite various
reminders and without any reason given.
Google shows that numerous people are hitting this issue. The issue is in
itself relatively minor, but the bug in the code is clear.
The patches have been in all my kernels and today testing has shown that
throttling works correctly with the patches applied when the system
overheats (http://bugzilla.kernel.org/show_bug.cgi?id=13918#c14).
Signed-off-by: Frans Pop <elendil@planet.nl>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
index 39838c6..31adda1 100644
--- a/drivers/acpi/processor_thermal.c
+++ b/drivers/acpi/processor_thermal.c
@@ -66,7 +66,7 @@
if (pr->limit.thermal.tx > tx)
tx = pr->limit.thermal.tx;
- result = acpi_processor_set_throttling(pr, tx);
+ result = acpi_processor_set_throttling(pr, tx, false);
if (result)
goto end;
}
@@ -421,12 +421,12 @@
if (state <= max_pstate) {
if (pr->flags.throttling && pr->throttling.state)
- result = acpi_processor_set_throttling(pr, 0);
+ result = acpi_processor_set_throttling(pr, 0, false);
cpufreq_set_cur_state(pr->id, state);
} else {
cpufreq_set_cur_state(pr->id, max_pstate);
result = acpi_processor_set_throttling(pr,
- state - max_pstate);
+ state - max_pstate, false);
}
return result;
}
diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 2275437..841be4e 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -62,7 +62,8 @@
#define THROTTLING_POSTCHANGE (2)
static int acpi_processor_get_throttling(struct acpi_processor *pr);
-int acpi_processor_set_throttling(struct acpi_processor *pr, int state);
+int acpi_processor_set_throttling(struct acpi_processor *pr,
+ int state, bool force);
static int acpi_processor_update_tsd_coord(void)
{
@@ -361,7 +362,7 @@
*/
target_state = throttling_limit;
}
- return acpi_processor_set_throttling(pr, target_state);
+ return acpi_processor_set_throttling(pr, target_state, false);
}
/*
@@ -842,7 +843,7 @@
ACPI_WARNING((AE_INFO,
"Invalid throttling state, reset"));
state = 0;
- ret = acpi_processor_set_throttling(pr, state);
+ ret = acpi_processor_set_throttling(pr, state, true);
if (ret)
return ret;
}
@@ -915,7 +916,7 @@
}
static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
- int state)
+ int state, bool force)
{
u32 value = 0;
u32 duty_mask = 0;
@@ -930,7 +931,7 @@
if (!pr->flags.throttling)
return -ENODEV;
- if (state == pr->throttling.state)
+ if (!force && (state == pr->throttling.state))
return 0;
if (state < pr->throttling_platform_limit)
@@ -988,7 +989,7 @@
}
static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
- int state)
+ int state, bool force)
{
int ret;
acpi_integer value;
@@ -1002,7 +1003,7 @@
if (!pr->flags.throttling)
return -ENODEV;
- if (state == pr->throttling.state)
+ if (!force && (state == pr->throttling.state))
return 0;
if (state < pr->throttling_platform_limit)
@@ -1018,7 +1019,8 @@
return 0;
}
-int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
+int acpi_processor_set_throttling(struct acpi_processor *pr,
+ int state, bool force)
{
cpumask_var_t saved_mask;
int ret = 0;
@@ -1070,7 +1072,7 @@
/* FIXME: use work_on_cpu() */
set_cpus_allowed_ptr(current, cpumask_of(pr->id));
ret = p_throttling->acpi_processor_set_throttling(pr,
- t_state.target_state);
+ t_state.target_state, force);
} else {
/*
* When the T-state coordination is SW_ALL or HW_ALL,
@@ -1103,7 +1105,7 @@
set_cpus_allowed_ptr(current, cpumask_of(i));
ret = match_pr->throttling.
acpi_processor_set_throttling(
- match_pr, t_state.target_state);
+ match_pr, t_state.target_state, force);
}
}
/*
@@ -1201,7 +1203,7 @@
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Disabling throttling (was T%d)\n",
pr->throttling.state));
- result = acpi_processor_set_throttling(pr, 0);
+ result = acpi_processor_set_throttling(pr, 0, false);
if (result)
goto end;
}
@@ -1307,7 +1309,7 @@
if (strcmp(tmpbuf, charp) != 0)
return -EINVAL;
- result = acpi_processor_set_throttling(pr, state_val);
+ result = acpi_processor_set_throttling(pr, state_val, false);
if (result)
return result;