Merge tag 'pm+acpi-3.11-rc1-more' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power management and ACPI updates from Rafael Wysocki:

 - Fix for a recent cpufreq regression that caused WARN() to trigger
   overzealously in a couple of places and spam the kernel log with
   useless garbage as a result.  From Viresh Kumar.

 - ACPI dock fix removing a discrepancy between the definition of
   acpi_dock_init(), which says that the function returns int, and its
   header in the header file, which says that it is a void function.
   The function is now defined as void too.

 - ACPI PM fix for failures to update device power states as needed, for
   example, during resume from system suspend, because the old state was
   deeper than the new one, but the new one is not D0.

 - Fix for two debug messages in the ACPI power resources code that
   don't have a newline at the end and make the kernel log difficult to
   read.  From Mika Westerberg.

 - Two ACPI cleanups from Naresh Bhat and Haicheng Li.

 - cpupower updates from Thomas Renninger, including Intel Haswell
   support improvements and a new idle-set subcommand among other
   things.

* tag 'pm+acpi-3.11-rc1-more' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / power: add missing newline to debug messages
  cpupower: Add Haswell family 0x45 specific idle monitor to show PC8,9,10 states
  cpupower: Haswell also supports the C-states introduced with SandyBridge
  cpupower: Introduce idle-set subcommand and C-state enabling/disabling
  cpupower: Implement disabling of cstate interface
  cpupower: Make idlestate usage unsigned
  ACPI / fan: Initialize acpi_state variable
  ACPI / scan: remove unused LIST_HEAD(acpi_device_list)
  ACPI / dock: Actually define acpi_dock_init() as void
  ACPI / PM: Fix corner case in acpi_bus_update_power()
  cpufreq: Fix serialization of frequency transitions

2 files changed, 125 insertions, 3 deletions

diff --git a/tools/power/cpupower/utils/helpers/sysfs.c b/tools/power/cpupower/utils/helpers/sysfs.c
index 38ab91629463..5cdc600e8152 100644
--- a/tools/power/cpupower/utils/helpers/sysfs.c
+++ b/tools/power/cpupower/utils/helpers/sysfs.c
@@ -89,6 +89,33 @@ int sysfs_is_cpu_online(unsigned int cpu)
 
 /* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
 
+
+/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+
+/*
+ * helper function to check whether a file under "../cpuX/cpuidle/stateX/" dir
+ * exists.
+ * For example the functionality to disable c-states was introduced in later
+ * kernel versions, this function can be used to explicitly check for this
+ * feature.
+ *
+ * returns 1 if the file exists, 0 otherwise.
+ */
+unsigned int sysfs_idlestate_file_exists(unsigned int cpu,
+					 unsigned int idlestate,
+					 const char *fname)
+{
+	char path[SYSFS_PATH_MAX];
+	struct stat statbuf;
+
+
+	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+		 cpu, idlestate, fname);
+	if (stat(path, &statbuf) != 0)
+		return 0;
+	return 1;
+}
+
 /*
  * helper function to read file from /sys into given buffer
  * fname is a relative path under "cpuX/cpuidle/stateX/" dir
@@ -121,6 +148,40 @@ unsigned int sysfs_idlestate_read_file(unsigned int cpu, unsigned int idlestate,
 	return (unsigned int) numread;
 }
 
+/* 
+ * helper function to write a new value to a /sys file
+ * fname is a relative path under "../cpuX/cpuidle/cstateY/" dir
+ *
+ * Returns the number of bytes written or 0 on error
+ */
+static
+unsigned int sysfs_idlestate_write_file(unsigned int cpu,
+					unsigned int idlestate,
+					const char *fname,
+					const char *value, size_t len)
+{
+	char path[SYSFS_PATH_MAX];
+	int fd;
+	ssize_t numwrite;
+
+	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+		 cpu, idlestate, fname);
+
+	fd = open(path, O_WRONLY);
+	if (fd == -1)
+		return 0;
+
+	numwrite = write(fd, value, len);
+	if (numwrite < 1) {
+		close(fd);
+		return 0;
+	}
+
+	close(fd);
+
+	return (unsigned int) numwrite;
+}
+
 /* read access to files which contain one numeric value */
 
 enum idlestate_value {
@@ -128,6 +189,7 @@ enum idlestate_value {
 	IDLESTATE_POWER,
 	IDLESTATE_LATENCY,
 	IDLESTATE_TIME,
+	IDLESTATE_DISABLE,
 	MAX_IDLESTATE_VALUE_FILES
 };
 
@@ -136,6 +198,7 @@ static const char *idlestate_value_files[MAX_IDLESTATE_VALUE_FILES] = {
 	[IDLESTATE_POWER] = "power",
 	[IDLESTATE_LATENCY] = "latency",
 	[IDLESTATE_TIME]  = "time",
+	[IDLESTATE_DISABLE]  = "disable",
 };
 
 static unsigned long long sysfs_idlestate_get_one_value(unsigned int cpu,
@@ -205,8 +268,59 @@ static char *sysfs_idlestate_get_one_string(unsigned int cpu,
 	return result;
 }
 
+/*
+ * Returns:
+ *    1  if disabled
+ *    0  if enabled
+ *    -1 if idlestate is not available
+ *    -2 if disabling is not supported by the kernel
+ */
+int sysfs_is_idlestate_disabled(unsigned int cpu,
+				unsigned int idlestate)
+{
+	if (sysfs_get_idlestate_count(cpu) < idlestate)
+		return -1;
+
+	if (!sysfs_idlestate_file_exists(cpu, idlestate,
+				 idlestate_value_files[IDLESTATE_DISABLE]))
+		return -2;
+	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_DISABLE);
+}
+
+/*
+ * Pass 1 as last argument to disable or 0 to enable the state
+ * Returns:
+ *    0  on success
+ *    negative values on error, for example:
+ *      -1 if idlestate is not available
+ *      -2 if disabling is not supported by the kernel
+ *      -3 No write access to disable/enable C-states
+ */
+int sysfs_idlestate_disable(unsigned int cpu,
+			    unsigned int idlestate,
+			    unsigned int disable)
+{
+	char value[SYSFS_PATH_MAX];
+	int bytes_written;
+
+	if (sysfs_get_idlestate_count(cpu) < idlestate)
+		return -1;
+
+	if (!sysfs_idlestate_file_exists(cpu, idlestate,
+				 idlestate_value_files[IDLESTATE_DISABLE]))
+		return -2;
+
+	snprintf(value, SYSFS_PATH_MAX, "%u", disable);
+
+	bytes_written = sysfs_idlestate_write_file(cpu, idlestate, "disable",
+						   value, sizeof(disable));
+	if (bytes_written)
+		return 0;
+	return -3;
+}
+
 unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
-					unsigned int idlestate)
+					  unsigned int idlestate)
 {
 	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_LATENCY);
 }
@@ -238,7 +352,7 @@ char *sysfs_get_idlestate_desc(unsigned int cpu, unsigned int idlestate)
  * Negativ in error case
  * Zero if cpuidle does not export any C-states
  */
-int sysfs_get_idlestate_count(unsigned int cpu)
+unsigned int sysfs_get_idlestate_count(unsigned int cpu)
 {
 	char file[SYSFS_PATH_MAX];
 	struct stat statbuf;
diff --git a/tools/power/cpupower/utils/helpers/sysfs.h b/tools/power/cpupower/utils/helpers/sysfs.h
index 8cb797bbceb0..d28f11fedbda 100644
--- a/tools/power/cpupower/utils/helpers/sysfs.h
+++ b/tools/power/cpupower/utils/helpers/sysfs.h
@@ -7,8 +7,16 @@
 
 extern unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen);
 
+extern unsigned int sysfs_idlestate_file_exists(unsigned int cpu,
+						unsigned int idlestate,
+						const char *fname);
+
 extern int sysfs_is_cpu_online(unsigned int cpu);
 
+extern int sysfs_is_idlestate_disabled(unsigned int cpu,
+				       unsigned int idlestate);
+extern int sysfs_idlestate_disable(unsigned int cpu, unsigned int idlestate,
+				   unsigned int disable);
 extern unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
 						unsigned int idlestate);
 extern unsigned long sysfs_get_idlestate_usage(unsigned int cpu,
@@ -19,7 +27,7 @@ extern char *sysfs_get_idlestate_name(unsigned int cpu,
 				unsigned int idlestate);
 extern char *sysfs_get_idlestate_desc(unsigned int cpu,
 				unsigned int idlestate);
-extern int sysfs_get_idlestate_count(unsigned int cpu);
+extern unsigned int sysfs_get_idlestate_count(unsigned int cpu);
 
 extern char *sysfs_get_cpuidle_governor(void);
 extern char *sysfs_get_cpuidle_driver(void);