| Message ID | 1492489799-6452-2-git-send-email-j-keerthy@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tuesday 18 April 2017 09:59 AM, Keerthy wrote: > orderly_poweroff is triggered when a graceful shutdown > of system is desired. This may be used in many critical states of the > kernel such as when subsystems detects conditions such as critical > temperature conditions. However, in certain conditions in system > boot up sequences like those in the middle of driver probes being > initiated, userspace will be unable to power off the system in a clean > manner and leaves the system in a critical state. In cases like these, > the /sbin/poweroff will return success (having forked off to attempt > powering off the system. However, the system overall will fail to > completely poweroff (since other modules will be probed) and the system > is still functional with no userspace (since that would have shut itself > off). > > However, there is no clean way of detecting such failure of userspace > powering off the system. In such scenarios, it is necessary for a backup > workqueue to be able to force a shutdown of the system when orderly > shutdown is not successful after a configurable time period. Care to add testing information? > Reported-by: Nishanth Menon <nm@ti.com> > Signed-off-by: Keerthy <j-keerthy@ti.com> > Acked-by: Eduardo Valentin <edubezval@gmail.com> > --- > > Changes in v6: > > * Rephrased Kconfig description as per Eduardo's feedback. > * Added check to verify positive values of delay in milli Seconds. > > Changes in v5: > > * Mandated delay for thermal emergency poweroff to be a non-zero value. > > Changes in v4: > > * Updated documentation > * changed emergency_poweroff_func to thermal_emergency_poweroff_func > > Changes in v3: > > * Removed unnecessary mutex init. > * Added WARN messages instead of a simple warning message. > * Added Documentation. > > Documentation/thermal/sysfs-api.txt | 21 +++++++++++++++ > drivers/thermal/Kconfig | 17 ++++++++++++ > drivers/thermal/thermal_core.c | 53 +++++++++++++++++++++++++++++++++++++ > 3 files changed, 91 insertions(+) > > diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt > index ef473dc..bb9a0a5 100644 > --- a/Documentation/thermal/sysfs-api.txt > +++ b/Documentation/thermal/sysfs-api.txt > @@ -582,3 +582,24 @@ platform data is provided, this uses the step_wise throttling policy. > This function serves as an arbitrator to set the state of a cooling > device. It sets the cooling device to the deepest cooling state if > possible. > + > +6. thermal_emergency_poweroff: > + Should this be in sysfs-api doc? > +On an event of critical trip temperature crossing. Thermal framework > +allows the system to shutdown gracefully by calling orderly_poweroff(). > +In the event of a failure of orderly_poweroff() to shut down the system > +we are in danger of keeping the system alive at undesirably high > +temperatures. To mitigate this high risk scenario we program a work > +queue to fire after a pre-determined number of seconds to start > +an emergency shutdown of the device using the kernel_power_off() > +function. In case kernel_power_off() fails then finally > +emergency_restart() is called in the worst case. > + > +The delay should be carefully profiled so as to give adequate time for > +orderly_poweroff(). In case of failure of an orderly_poweroff() the > +emergency poweroff kicks in after the delay has elapsed and shuts down > +the system. > + In order to come up with an ideal delay, we need to strike a balance between being paranoid vs being too late. In a different patch, I tried to justify setting crit temp @120C by quoting we need to give some time to orderly_poweroff() So we got T = [3/temp change rate] seconds before the HW issues a reset. within this T sec we need to give a chance to orderly_poweroff() and when it fails, bring out the big weapons. crumb: we might actually be increasing the "temp rate change" by doing a lot of IO access for syncing. Let us hope someone is trying to cool the system down while we are trying to save the day.. > +If set to 0 emergency poweroff will not be supported. So a carefully > +profiled non-zero positive value is a must for emergerncy poweroff to be > +triggered. Profiling should be done based on real data than emulation. That's when we get to know if the memory and IOs listen to the SoC when the lava is out. > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig > index 9347401..74bf92b 100644 > --- a/drivers/thermal/Kconfig > +++ b/drivers/thermal/Kconfig > @@ -15,6 +15,23 @@ menuconfig THERMAL > > if THERMAL > > +config THERMAL_EMERGENCY_POWEROFF_DELAY_MS > + int "Emergency poweroff delay in milli-seconds" > + depends on THERMAL > + default 0 > + help > + Thermal subsystem will issue a graceful shutdown when > + critical temperatures are reached using orderly_poweroff(). In > + case of failure of an orderly_poweroff(), the thermal emergency > + poweroff kicks in after a delay has elapsed and shuts down the system. > + This config is number of milliseconds to delay before emergency > + poweroff kicks in. Similarly to the critical trip point, > + the delay should be carefully profiled so as to give adequate > + time for orderly_poweroff() to finish on regular execution. > + If set to 0 emergency poweroff will not be supported. > + > + In doubt, leave as 0. > + > config THERMAL_HWMON > bool > prompt "Expose thermal sensors as hwmon device" > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > index 8337c27..b21b9cc 100644 > --- a/drivers/thermal/thermal_core.c > +++ b/drivers/thermal/thermal_core.c > @@ -324,6 +324,54 @@ static void handle_non_critical_trips(struct thermal_zone_device *tz, > def_governor->throttle(tz, trip); > } > > +/** > + * thermal_emergency_poweroff_func - emergency poweroff work after a known delay may needs to be re-phrased as this func itself can't handle the delay. > + * @work: work_struct associated with the emergency poweroff function > + * > + * This function is called in very critical situations to force > + * a kernel poweroff after a configurable timeout value. > + */ > +static void thermal_emergency_poweroff_func(struct work_struct *work) > +{ > + /* > + * We have reached here after the emergency thermal shutdown > + * Waiting period has expired. This means orderly_poweroff has > + * not been able to shut off the system for some reason. > + * Try to shut down the system immediately using kernel_power_off > + * if populated > + */ > + WARN(1, "Attempting kernel_power_off: Temperature too high\n"); > + kernel_power_off(); > + > + /* > + * Worst of the worst case trigger emergency restart > + */ > + WARN(1, "Attempting emergency_restart: Temperature too high\n"); > + emergency_restart(); > +} > + > +static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work, > + thermal_emergency_poweroff_func); > + > +/** > + * thermal_emergency_poweroff - Trigger an emergency system poweroff Here you may say after a pre-set delay. > + * > + * This may be called from any critical situation to trigger a system shutdown > + * after a known period of time. By default this is not scheduled. This will be called only on a critical temperature event, right? > + */ > +void thermal_emergency_poweroff(void) > +{ > + int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS; > + /* > + * poweroff_delay_ms must be a carefully profiled positive value. > + * Its a must for thermal_emergency_poweroff_work to be scheduled typo %s/Its/It's/ > + */ > + if (poweroff_delay_ms <= 0) > + return; It may be helpful to provide hint before returning? "Back up thermal emergency poweroff service is not enabled, set CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS to a carefully profiled value to enable this service" > + schedule_delayed_work(&thermal_emergency_poweroff_work, > + msecs_to_jiffies(poweroff_delay_ms)); > +} > + > static void handle_critical_trips(struct thermal_zone_device *tz, > int trip, enum thermal_trip_type trip_type) > { > @@ -346,6 +394,11 @@ static void handle_critical_trips(struct thermal_zone_device *tz, > tz->temperature / 1000); > mutex_lock(&poweroff_lock); > if (!power_off_triggered) { > + /* > + * Queue a backup emergency shutdown in the event of > + * orderly_poweroff failure > + */ > + thermal_emergency_poweroff(); This comment is misleading because calling the api is not enough to set a backup. > orderly_poweroff(true); > power_off_triggered = true; > } Over all, much needed functionality. Thanks. Regards, RK -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday 18 April 2017 11:45 AM, Ravikumar wrote: > > > On Tuesday 18 April 2017 09:59 AM, Keerthy wrote: >> orderly_poweroff is triggered when a graceful shutdown >> of system is desired. This may be used in many critical states of the >> kernel such as when subsystems detects conditions such as critical >> temperature conditions. However, in certain conditions in system >> boot up sequences like those in the middle of driver probes being >> initiated, userspace will be unable to power off the system in a clean >> manner and leaves the system in a critical state. In cases like these, >> the /sbin/poweroff will return success (having forked off to attempt >> powering off the system. However, the system overall will fail to >> completely poweroff (since other modules will be probed) and the system >> is still functional with no userspace (since that would have shut itself >> off). >> >> However, there is no clean way of detecting such failure of userspace >> powering off the system. In such scenarios, it is necessary for a backup >> workqueue to be able to force a shutdown of the system when orderly >> shutdown is not successful after a configurable time period. > Care to add testing information? I used THERMAL_EMULATION to fake temperature more than trip point. If the delay is lesser (< 20S) then i see that backup poweroff is called and the system shuts down immediately after the delay time expires else orderly_poweroff gracefully shuts off the system. I do not have the logs right now. >> Reported-by: Nishanth Menon <nm@ti.com> >> Signed-off-by: Keerthy <j-keerthy@ti.com> >> Acked-by: Eduardo Valentin <edubezval@gmail.com> >> --- >> >> Changes in v6: >> >> * Rephrased Kconfig description as per Eduardo's feedback. >> * Added check to verify positive values of delay in milli Seconds. >> >> Changes in v5: >> >> * Mandated delay for thermal emergency poweroff to be a non-zero >> value. >> >> Changes in v4: >> >> * Updated documentation >> * changed emergency_poweroff_func to thermal_emergency_poweroff_func >> >> Changes in v3: >> >> * Removed unnecessary mutex init. >> * Added WARN messages instead of a simple warning message. >> * Added Documentation. >> >> Documentation/thermal/sysfs-api.txt | 21 +++++++++++++++ >> drivers/thermal/Kconfig | 17 ++++++++++++ >> drivers/thermal/thermal_core.c | 53 >> +++++++++++++++++++++++++++++++++++++ >> 3 files changed, 91 insertions(+) >> >> diff --git a/Documentation/thermal/sysfs-api.txt >> b/Documentation/thermal/sysfs-api.txt >> index ef473dc..bb9a0a5 100644 >> --- a/Documentation/thermal/sysfs-api.txt >> +++ b/Documentation/thermal/sysfs-api.txt >> @@ -582,3 +582,24 @@ platform data is provided, this uses the >> step_wise throttling policy. >> This function serves as an arbitrator to set the state of a cooling >> device. It sets the cooling device to the deepest cooling state if >> possible. >> + >> +6. thermal_emergency_poweroff: >> + > Should this be in sysfs-api doc? >> +On an event of critical trip temperature crossing. Thermal framework >> +allows the system to shutdown gracefully by calling orderly_poweroff(). >> +In the event of a failure of orderly_poweroff() to shut down the system >> +we are in danger of keeping the system alive at undesirably high >> +temperatures. To mitigate this high risk scenario we program a work >> +queue to fire after a pre-determined number of seconds to start >> +an emergency shutdown of the device using the kernel_power_off() >> +function. In case kernel_power_off() fails then finally >> +emergency_restart() is called in the worst case. >> + >> +The delay should be carefully profiled so as to give adequate time for >> +orderly_poweroff(). In case of failure of an orderly_poweroff() the >> +emergency poweroff kicks in after the delay has elapsed and shuts down >> +the system. >> + > In order to come up with an ideal delay, we need to strike a balance > between > being paranoid vs being too late. > In a different patch, I tried to justify setting crit temp @120C by quoting > we need to give some time to orderly_poweroff() > > So we got T = [3/temp change rate] seconds before the HW issues a reset. > > within this T sec we need to give a chance to orderly_poweroff() and > when it > fails, bring out the big weapons. > > crumb: we might actually be increasing the "temp rate change" by doing a > lot of IO > access for syncing. > Let us hope someone is trying to cool the system down while we are > trying to > save the day.. >> +If set to 0 emergency poweroff will not be supported. So a carefully >> +profiled non-zero positive value is a must for emergerncy poweroff to be >> +triggered. > Profiling should be done based on real data than emulation. > That's when we get to know if the memory and IOs listen to the SoC > when the lava is out. >> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig >> index 9347401..74bf92b 100644 >> --- a/drivers/thermal/Kconfig >> +++ b/drivers/thermal/Kconfig >> @@ -15,6 +15,23 @@ menuconfig THERMAL >> if THERMAL >> +config THERMAL_EMERGENCY_POWEROFF_DELAY_MS >> + int "Emergency poweroff delay in milli-seconds" >> + depends on THERMAL >> + default 0 >> + help >> + Thermal subsystem will issue a graceful shutdown when >> + critical temperatures are reached using orderly_poweroff(). In >> + case of failure of an orderly_poweroff(), the thermal emergency >> + poweroff kicks in after a delay has elapsed and shuts down the >> system. >> + This config is number of milliseconds to delay before emergency >> + poweroff kicks in. Similarly to the critical trip point, >> + the delay should be carefully profiled so as to give adequate >> + time for orderly_poweroff() to finish on regular execution. >> + If set to 0 emergency poweroff will not be supported. >> + >> + In doubt, leave as 0. >> + >> config THERMAL_HWMON >> bool >> prompt "Expose thermal sensors as hwmon device" >> diff --git a/drivers/thermal/thermal_core.c >> b/drivers/thermal/thermal_core.c >> index 8337c27..b21b9cc 100644 >> --- a/drivers/thermal/thermal_core.c >> +++ b/drivers/thermal/thermal_core.c >> @@ -324,6 +324,54 @@ static void handle_non_critical_trips(struct >> thermal_zone_device *tz, >> def_governor->throttle(tz, trip); >> } >> +/** >> + * thermal_emergency_poweroff_func - emergency poweroff work after a >> known delay > may needs to be re-phrased as this func itself can't handle the delay. >> + * @work: work_struct associated with the emergency poweroff function >> + * >> + * This function is called in very critical situations to force >> + * a kernel poweroff after a configurable timeout value. >> + */ >> +static void thermal_emergency_poweroff_func(struct work_struct *work) >> +{ >> + /* >> + * We have reached here after the emergency thermal shutdown >> + * Waiting period has expired. This means orderly_poweroff has >> + * not been able to shut off the system for some reason. >> + * Try to shut down the system immediately using kernel_power_off >> + * if populated >> + */ >> + WARN(1, "Attempting kernel_power_off: Temperature too high\n"); >> + kernel_power_off(); >> + >> + /* >> + * Worst of the worst case trigger emergency restart >> + */ >> + WARN(1, "Attempting emergency_restart: Temperature too high\n"); >> + emergency_restart(); >> +} >> + >> +static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work, >> + thermal_emergency_poweroff_func); >> + >> +/** >> + * thermal_emergency_poweroff - Trigger an emergency system poweroff > Here you may say after a pre-set delay. >> + * >> + * This may be called from any critical situation to trigger a system >> shutdown >> + * after a known period of time. By default this is not scheduled. > This will be called only on a critical temperature event, right? >> + */ >> +void thermal_emergency_poweroff(void) >> +{ >> + int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS; >> + /* >> + * poweroff_delay_ms must be a carefully profiled positive value. >> + * Its a must for thermal_emergency_poweroff_work to be scheduled > typo %s/Its/It's/ >> + */ >> + if (poweroff_delay_ms <= 0) >> + return; > It may be helpful to provide hint before returning? > "Back up thermal emergency poweroff service is not enabled, set > > CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS to a carefully profiled value > to enable this service" > >> + schedule_delayed_work(&thermal_emergency_poweroff_work, >> + msecs_to_jiffies(poweroff_delay_ms)); >> +} >> + >> static void handle_critical_trips(struct thermal_zone_device *tz, >> int trip, enum thermal_trip_type trip_type) >> { >> @@ -346,6 +394,11 @@ static void handle_critical_trips(struct >> thermal_zone_device *tz, >> tz->temperature / 1000); >> mutex_lock(&poweroff_lock); >> if (!power_off_triggered) { >> + /* >> + * Queue a backup emergency shutdown in the event of >> + * orderly_poweroff failure >> + */ >> + thermal_emergency_poweroff(); > This comment is misleading because calling the api is not enough to set > a backup. >> orderly_poweroff(true); >> power_off_triggered = true; >> } > Over all, much needed functionality. Thanks. > > Regards, > RK -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday 18 April 2017 11:48 AM, Keerthy wrote: > > > On Tuesday 18 April 2017 11:45 AM, Ravikumar wrote: >> >> >> On Tuesday 18 April 2017 09:59 AM, Keerthy wrote: >>> orderly_poweroff is triggered when a graceful shutdown >>> of system is desired. This may be used in many critical states of the >>> kernel such as when subsystems detects conditions such as critical >>> temperature conditions. However, in certain conditions in system >>> boot up sequences like those in the middle of driver probes being >>> initiated, userspace will be unable to power off the system in a clean >>> manner and leaves the system in a critical state. In cases like these, >>> the /sbin/poweroff will return success (having forked off to attempt >>> powering off the system. However, the system overall will fail to >>> completely poweroff (since other modules will be probed) and the system >>> is still functional with no userspace (since that would have shut itself >>> off). >>> >>> However, there is no clean way of detecting such failure of userspace >>> powering off the system. In such scenarios, it is necessary for a backup >>> workqueue to be able to force a shutdown of the system when orderly >>> shutdown is not successful after a configurable time period. >> Care to add testing information? > > I used THERMAL_EMULATION to fake temperature more than trip point. > If the delay is lesser (< 20S) then i see that backup poweroff is called > and the system shuts down immediately after the delay time expires else > orderly_poweroff gracefully shuts off the system. I do not have the logs > right now. > >>> Reported-by: Nishanth Menon <nm@ti.com> >>> Signed-off-by: Keerthy <j-keerthy@ti.com> >>> Acked-by: Eduardo Valentin <edubezval@gmail.com> Zhang, Could you pull this one also? - Keerthy >>> --- >>> >>> Changes in v6: >>> >>> * Rephrased Kconfig description as per Eduardo's feedback. >>> * Added check to verify positive values of delay in milli Seconds. >>> >>> Changes in v5: >>> >>> * Mandated delay for thermal emergency poweroff to be a non-zero >>> value. >>> >>> Changes in v4: >>> >>> * Updated documentation >>> * changed emergency_poweroff_func to thermal_emergency_poweroff_func >>> >>> Changes in v3: >>> >>> * Removed unnecessary mutex init. >>> * Added WARN messages instead of a simple warning message. >>> * Added Documentation. >>> >>> Documentation/thermal/sysfs-api.txt | 21 +++++++++++++++ >>> drivers/thermal/Kconfig | 17 ++++++++++++ >>> drivers/thermal/thermal_core.c | 53 >>> +++++++++++++++++++++++++++++++++++++ >>> 3 files changed, 91 insertions(+) >>> >>> diff --git a/Documentation/thermal/sysfs-api.txt >>> b/Documentation/thermal/sysfs-api.txt >>> index ef473dc..bb9a0a5 100644 >>> --- a/Documentation/thermal/sysfs-api.txt >>> +++ b/Documentation/thermal/sysfs-api.txt >>> @@ -582,3 +582,24 @@ platform data is provided, this uses the >>> step_wise throttling policy. >>> This function serves as an arbitrator to set the state of a cooling >>> device. It sets the cooling device to the deepest cooling state if >>> possible. >>> + >>> +6. thermal_emergency_poweroff: >>> + >> Should this be in sysfs-api doc? >>> +On an event of critical trip temperature crossing. Thermal framework >>> +allows the system to shutdown gracefully by calling orderly_poweroff(). >>> +In the event of a failure of orderly_poweroff() to shut down the system >>> +we are in danger of keeping the system alive at undesirably high >>> +temperatures. To mitigate this high risk scenario we program a work >>> +queue to fire after a pre-determined number of seconds to start >>> +an emergency shutdown of the device using the kernel_power_off() >>> +function. In case kernel_power_off() fails then finally >>> +emergency_restart() is called in the worst case. >>> + >>> +The delay should be carefully profiled so as to give adequate time for >>> +orderly_poweroff(). In case of failure of an orderly_poweroff() the >>> +emergency poweroff kicks in after the delay has elapsed and shuts down >>> +the system. >>> + >> In order to come up with an ideal delay, we need to strike a balance >> between >> being paranoid vs being too late. >> In a different patch, I tried to justify setting crit temp @120C by quoting >> we need to give some time to orderly_poweroff() >> >> So we got T = [3/temp change rate] seconds before the HW issues a reset. >> >> within this T sec we need to give a chance to orderly_poweroff() and >> when it >> fails, bring out the big weapons. >> >> crumb: we might actually be increasing the "temp rate change" by doing a >> lot of IO >> access for syncing. >> Let us hope someone is trying to cool the system down while we are >> trying to >> save the day.. >>> +If set to 0 emergency poweroff will not be supported. So a carefully >>> +profiled non-zero positive value is a must for emergerncy poweroff to be >>> +triggered. >> Profiling should be done based on real data than emulation. >> That's when we get to know if the memory and IOs listen to the SoC >> when the lava is out. >>> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig >>> index 9347401..74bf92b 100644 >>> --- a/drivers/thermal/Kconfig >>> +++ b/drivers/thermal/Kconfig >>> @@ -15,6 +15,23 @@ menuconfig THERMAL >>> if THERMAL >>> +config THERMAL_EMERGENCY_POWEROFF_DELAY_MS >>> + int "Emergency poweroff delay in milli-seconds" >>> + depends on THERMAL >>> + default 0 >>> + help >>> + Thermal subsystem will issue a graceful shutdown when >>> + critical temperatures are reached using orderly_poweroff(). In >>> + case of failure of an orderly_poweroff(), the thermal emergency >>> + poweroff kicks in after a delay has elapsed and shuts down the >>> system. >>> + This config is number of milliseconds to delay before emergency >>> + poweroff kicks in. Similarly to the critical trip point, >>> + the delay should be carefully profiled so as to give adequate >>> + time for orderly_poweroff() to finish on regular execution. >>> + If set to 0 emergency poweroff will not be supported. >>> + >>> + In doubt, leave as 0. >>> + >>> config THERMAL_HWMON >>> bool >>> prompt "Expose thermal sensors as hwmon device" >>> diff --git a/drivers/thermal/thermal_core.c >>> b/drivers/thermal/thermal_core.c >>> index 8337c27..b21b9cc 100644 >>> --- a/drivers/thermal/thermal_core.c >>> +++ b/drivers/thermal/thermal_core.c >>> @@ -324,6 +324,54 @@ static void handle_non_critical_trips(struct >>> thermal_zone_device *tz, >>> def_governor->throttle(tz, trip); >>> } >>> +/** >>> + * thermal_emergency_poweroff_func - emergency poweroff work after a >>> known delay >> may needs to be re-phrased as this func itself can't handle the delay. >>> + * @work: work_struct associated with the emergency poweroff function >>> + * >>> + * This function is called in very critical situations to force >>> + * a kernel poweroff after a configurable timeout value. >>> + */ >>> +static void thermal_emergency_poweroff_func(struct work_struct *work) >>> +{ >>> + /* >>> + * We have reached here after the emergency thermal shutdown >>> + * Waiting period has expired. This means orderly_poweroff has >>> + * not been able to shut off the system for some reason. >>> + * Try to shut down the system immediately using kernel_power_off >>> + * if populated >>> + */ >>> + WARN(1, "Attempting kernel_power_off: Temperature too high\n"); >>> + kernel_power_off(); >>> + >>> + /* >>> + * Worst of the worst case trigger emergency restart >>> + */ >>> + WARN(1, "Attempting emergency_restart: Temperature too high\n"); >>> + emergency_restart(); >>> +} >>> + >>> +static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work, >>> + thermal_emergency_poweroff_func); >>> + >>> +/** >>> + * thermal_emergency_poweroff - Trigger an emergency system poweroff >> Here you may say after a pre-set delay. >>> + * >>> + * This may be called from any critical situation to trigger a system >>> shutdown >>> + * after a known period of time. By default this is not scheduled. >> This will be called only on a critical temperature event, right? >>> + */ >>> +void thermal_emergency_poweroff(void) >>> +{ >>> + int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS; >>> + /* >>> + * poweroff_delay_ms must be a carefully profiled positive value. >>> + * Its a must for thermal_emergency_poweroff_work to be scheduled >> typo %s/Its/It's/ >>> + */ >>> + if (poweroff_delay_ms <= 0) >>> + return; >> It may be helpful to provide hint before returning? >> "Back up thermal emergency poweroff service is not enabled, set >> >> CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS to a carefully profiled value >> to enable this service" >> >>> + schedule_delayed_work(&thermal_emergency_poweroff_work, >>> + msecs_to_jiffies(poweroff_delay_ms)); >>> +} >>> + >>> static void handle_critical_trips(struct thermal_zone_device *tz, >>> int trip, enum thermal_trip_type trip_type) >>> { >>> @@ -346,6 +394,11 @@ static void handle_critical_trips(struct >>> thermal_zone_device *tz, >>> tz->temperature / 1000); >>> mutex_lock(&poweroff_lock); >>> if (!power_off_triggered) { >>> + /* >>> + * Queue a backup emergency shutdown in the event of >>> + * orderly_poweroff failure >>> + */ >>> + thermal_emergency_poweroff(); >> This comment is misleading because calling the api is not enough to set >> a backup. >>> orderly_poweroff(true); >>> power_off_triggered = true; >>> } >> Over all, much needed functionality. Thanks. >> >> Regards, >> RK -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt index ef473dc..bb9a0a5 100644 --- a/Documentation/thermal/sysfs-api.txt +++ b/Documentation/thermal/sysfs-api.txt @@ -582,3 +582,24 @@ platform data is provided, this uses the step_wise throttling policy. This function serves as an arbitrator to set the state of a cooling device. It sets the cooling device to the deepest cooling state if possible. + +6. thermal_emergency_poweroff: + +On an event of critical trip temperature crossing. Thermal framework +allows the system to shutdown gracefully by calling orderly_poweroff(). +In the event of a failure of orderly_poweroff() to shut down the system +we are in danger of keeping the system alive at undesirably high +temperatures. To mitigate this high risk scenario we program a work +queue to fire after a pre-determined number of seconds to start +an emergency shutdown of the device using the kernel_power_off() +function. In case kernel_power_off() fails then finally +emergency_restart() is called in the worst case. + +The delay should be carefully profiled so as to give adequate time for +orderly_poweroff(). In case of failure of an orderly_poweroff() the +emergency poweroff kicks in after the delay has elapsed and shuts down +the system. + +If set to 0 emergency poweroff will not be supported. So a carefully +profiled non-zero positive value is a must for emergerncy poweroff to be +triggered. diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 9347401..74bf92b 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -15,6 +15,23 @@ menuconfig THERMAL if THERMAL +config THERMAL_EMERGENCY_POWEROFF_DELAY_MS + int "Emergency poweroff delay in milli-seconds" + depends on THERMAL + default 0 + help + Thermal subsystem will issue a graceful shutdown when + critical temperatures are reached using orderly_poweroff(). In + case of failure of an orderly_poweroff(), the thermal emergency + poweroff kicks in after a delay has elapsed and shuts down the system. + This config is number of milliseconds to delay before emergency + poweroff kicks in. Similarly to the critical trip point, + the delay should be carefully profiled so as to give adequate + time for orderly_poweroff() to finish on regular execution. + If set to 0 emergency poweroff will not be supported. + + In doubt, leave as 0. + config THERMAL_HWMON bool prompt "Expose thermal sensors as hwmon device" diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c index 8337c27..b21b9cc 100644 --- a/drivers/thermal/thermal_core.c +++ b/drivers/thermal/thermal_core.c @@ -324,6 +324,54 @@ static void handle_non_critical_trips(struct thermal_zone_device *tz, def_governor->throttle(tz, trip); } +/** + * thermal_emergency_poweroff_func - emergency poweroff work after a known delay + * @work: work_struct associated with the emergency poweroff function + * + * This function is called in very critical situations to force + * a kernel poweroff after a configurable timeout value. + */ +static void thermal_emergency_poweroff_func(struct work_struct *work) +{ + /* + * We have reached here after the emergency thermal shutdown + * Waiting period has expired. This means orderly_poweroff has + * not been able to shut off the system for some reason. + * Try to shut down the system immediately using kernel_power_off + * if populated + */ + WARN(1, "Attempting kernel_power_off: Temperature too high\n"); + kernel_power_off(); + + /* + * Worst of the worst case trigger emergency restart + */ + WARN(1, "Attempting emergency_restart: Temperature too high\n"); + emergency_restart(); +} + +static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work, + thermal_emergency_poweroff_func); + +/** + * thermal_emergency_poweroff - Trigger an emergency system poweroff + * + * This may be called from any critical situation to trigger a system shutdown + * after a known period of time. By default this is not scheduled. + */ +void thermal_emergency_poweroff(void) +{ + int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS; + /* + * poweroff_delay_ms must be a carefully profiled positive value. + * Its a must for thermal_emergency_poweroff_work to be scheduled + */ + if (poweroff_delay_ms <= 0) + return; + schedule_delayed_work(&thermal_emergency_poweroff_work, + msecs_to_jiffies(poweroff_delay_ms)); +} + static void handle_critical_trips(struct thermal_zone_device *tz, int trip, enum thermal_trip_type trip_type) { @@ -346,6 +394,11 @@ static void handle_critical_trips(struct thermal_zone_device *tz, tz->temperature / 1000); mutex_lock(&poweroff_lock); if (!power_off_triggered) { + /* + * Queue a backup emergency shutdown in the event of + * orderly_poweroff failure + */ + thermal_emergency_poweroff(); orderly_poweroff(true); power_off_triggered = true; }