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authorFrans Pop <elendil@planet.nl>2009-08-26 17:29:29 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-26 23:06:53 -0400
commit2a908002c7b1b666616103e9df2419b38d7c6f1f (patch)
treee525ac0c224091b1d71ffa9aec4c4f39c8223c62 /include/acpi
parentf3d83e2415445e5b157bef404d38674e9e8de169 (diff)
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>
Diffstat (limited to 'include/acpi')
-rw-r--r--include/acpi/processor.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index baf1e0a9a7ee..740ac3ad8fd0 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -174,7 +174,7 @@ struct acpi_processor_throttling {
174 cpumask_var_t shared_cpu_map; 174 cpumask_var_t shared_cpu_map;
175 int (*acpi_processor_get_throttling) (struct acpi_processor * pr); 175 int (*acpi_processor_get_throttling) (struct acpi_processor * pr);
176 int (*acpi_processor_set_throttling) (struct acpi_processor * pr, 176 int (*acpi_processor_set_throttling) (struct acpi_processor * pr,
177 int state); 177 int state, bool force);
178 178
179 u32 address; 179 u32 address;
180 u8 duty_offset; 180 u8 duty_offset;
@@ -321,7 +321,8 @@ static inline int acpi_processor_ppc_has_changed(struct acpi_processor *pr)
321/* in processor_throttling.c */ 321/* in processor_throttling.c */
322int acpi_processor_tstate_has_changed(struct acpi_processor *pr); 322int acpi_processor_tstate_has_changed(struct acpi_processor *pr);
323int acpi_processor_get_throttling_info(struct acpi_processor *pr); 323int acpi_processor_get_throttling_info(struct acpi_processor *pr);
324extern int acpi_processor_set_throttling(struct acpi_processor *pr, int state); 324extern int acpi_processor_set_throttling(struct acpi_processor *pr,
325 int state, bool force);
325extern const struct file_operations acpi_processor_throttling_fops; 326extern const struct file_operations acpi_processor_throttling_fops;
326extern void acpi_processor_throttling_init(void); 327extern void acpi_processor_throttling_init(void);
327/* in processor_idle.c */ 328/* in processor_idle.c */