diff options
| -rw-r--r-- | Documentation/ibm-acpi.txt | 20 | ||||
| -rw-r--r-- | drivers/acpi/ibm_acpi.c | 70 |
2 files changed, 87 insertions, 3 deletions
diff --git a/Documentation/ibm-acpi.txt b/Documentation/ibm-acpi.txt index cbd3a603a7ef..0132d363feb5 100644 --- a/Documentation/ibm-acpi.txt +++ b/Documentation/ibm-acpi.txt @@ -670,6 +670,26 @@ example: modprobe ibm_acpi hotkey=enable,0xffff video=auto_disable +The ibm-acpi kernel driver can be programmed to revert the fan level +to a safe setting if userspace does not issue one of the fan commands: +"enable", "disable", "level" or "watchdog" within a configurable +ammount of time. To do this, use the "watchdog" command. + + echo 'watchdog <interval>' > /proc/acpi/ibm/fan + +Interval is the ammount of time in seconds to wait for one of the +above mentioned fan commands before reseting the fan level to a safe +one. If set to zero, the watchdog is disabled (default). When the +watchdog timer runs out, it does the exact equivalent of the "enable" +fan command. + +Note that the watchdog timer stops after it enables the fan. It will +be rearmed again automatically (using the same interval) when one of +the above mentioned fan commands is received. The fan watchdog is, +therefore, not suitable to protect against fan mode changes made +through means other than the "enable", "disable", and "level" fan +commands. + Example Configuration --------------------- diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c index 56743c5a0439..e5b8745b9070 100644 --- a/drivers/acpi/ibm_acpi.c +++ b/drivers/acpi/ibm_acpi.c @@ -82,6 +82,8 @@ #include <linux/backlight.h> #include <asm/uaccess.h> #include <linux/dmi.h> +#include <linux/jiffies.h> +#include <linux/workqueue.h> #include <acpi/acpi_drivers.h> #include <acpi/acnamesp.h> @@ -348,7 +350,8 @@ enum fan_control_access_mode { enum fan_control_commands { IBMACPI_FAN_CMD_SPEED = 0x0001, /* speed command */ IBMACPI_FAN_CMD_LEVEL = 0x0002, /* level command */ - IBMACPI_FAN_CMD_ENABLE = 0x0004, /* enable/disable cmd */ + IBMACPI_FAN_CMD_ENABLE = 0x0004, /* enable/disable cmd, + * and also watchdog cmd */ }; enum { /* Fan control constants */ @@ -1797,12 +1800,17 @@ static enum fan_control_commands fan_control_commands; static int fan_control_status_known; static u8 fan_control_initial_status; +static void fan_watchdog_fire(void *ignored); +static int fan_watchdog_maxinterval; +static DECLARE_WORK(fan_watchdog_task, fan_watchdog_fire, NULL); + static int fan_init(void) { fan_status_access_mode = IBMACPI_FAN_NONE; fan_control_access_mode = IBMACPI_FAN_WR_NONE; fan_control_commands = 0; fan_control_status_known = 1; + fan_watchdog_maxinterval = 0; if (gfan_handle) { /* 570, 600e/x, 770e, 770x */ @@ -1934,6 +1942,31 @@ static int fan_get_speed(unsigned int *speed) return 0; } +static void fan_exit(void) +{ + cancel_delayed_work(&fan_watchdog_task); + flush_scheduled_work(); +} + +static void fan_watchdog_reset(void) +{ + static int fan_watchdog_active = 0; + + if (fan_watchdog_active) + cancel_delayed_work(&fan_watchdog_task); + + if (fan_watchdog_maxinterval > 0) { + fan_watchdog_active = 1; + if (!schedule_delayed_work(&fan_watchdog_task, + msecs_to_jiffies(fan_watchdog_maxinterval + * 1000))) { + printk(IBM_ERR "failed to schedule the fan watchdog, " + "watchdog will not trigger\n"); + } + } else + fan_watchdog_active = 0; +} + static int fan_read(char *p) { int len = 0; @@ -2007,7 +2040,9 @@ static int fan_read(char *p) } if (fan_control_commands & IBMACPI_FAN_CMD_ENABLE) - len += sprintf(p + len, "commands:\tenable, disable\n"); + len += sprintf(p + len, "commands:\tenable, disable\n" + "commands:\twatchdog <timeout> (<timeout> is 0 (off), " + "1-120 (seconds))\n"); if (fan_control_commands & IBMACPI_FAN_CMD_SPEED) len += sprintf(p + len, "commands:\tspeed <speed>" @@ -2186,6 +2221,21 @@ static int fan_write_cmd_speed(const char *cmd, int *rc) return 1; } +static int fan_write_cmd_watchdog(const char *cmd, int *rc) +{ + int interval; + + if (sscanf(cmd, "watchdog %d", &interval) != 1) + return 0; + + if (interval < 0 || interval > 120) + *rc = -EINVAL; + else + fan_watchdog_maxinterval = interval; + + return 1; +} + static int fan_write(char *buf) { char *cmd; @@ -2196,16 +2246,29 @@ static int fan_write(char *buf) fan_write_cmd_level(cmd, &rc)) && !((fan_control_commands & IBMACPI_FAN_CMD_ENABLE) && (fan_write_cmd_enable(cmd, &rc) || - fan_write_cmd_disable(cmd, &rc))) && + fan_write_cmd_disable(cmd, &rc) || + fan_write_cmd_watchdog(cmd, &rc))) && !((fan_control_commands & IBMACPI_FAN_CMD_SPEED) && fan_write_cmd_speed(cmd, &rc)) ) rc = -EINVAL; + else if (!rc) + fan_watchdog_reset(); } return rc; } +static void fan_watchdog_fire(void *ignored) +{ + printk(IBM_NOTICE "fan watchdog: enabling fan\n"); + if (fan_set_enable()) { + printk(IBM_ERR "fan watchdog: error while enabling fan\n"); + /* reschedule for later */ + fan_watchdog_reset(); + } +} + static struct ibm_struct ibms[] = { { .name = "driver", @@ -2317,6 +2380,7 @@ static struct ibm_struct ibms[] = { .read = fan_read, .write = fan_write, .init = fan_init, + .exit = fan_exit, .experimental = 1, }, }; |