| Message ID | 4950004.31r3eYUQgx@rjwysocki.net |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] thermal: core: Allow thermal zones to tell the core to ignore them | expand |
On Wed, Jul 17, 2024 at 09:45:02PM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > The iwlwifi wireless driver registers a thermal zone that is only needed > when the network interface handled by it is up and it wants that thermal > zone to be effectively ignored by the core otherwise. > > Before commit a8a261774466 ("thermal: core: Call monitor_thermal_zone() > if zone temperature is invalid") that could be achieved by returning > an error code from the thermal zone's .get_temp() callback because the > core did not really handle errors returned by it almost at all. > However, commit a8a261774466 made the core attempt to recover from the > situation in which the temperature of a thermal zone cannot be > determined due to errors returned by its .get_temp() and is always > invalid from the core's perspective. > > That was done because there are thermal zones in which .get_temp() > returns errors to start with due to some difficulties related to the > initialization ordering, but then it will start to produce valid > temperature values at one point. > > Unfortunately, the simple approach taken by commit a8a261774466, > which is to poll the thermal zone periodically until its .get_temp() > callback starts to return valid temperature values, is at odds with > the special thermal zone in iwlwifi in which .get_temp() may always > return an error because its network interface may always be down. If > that happens, every attempt to invoke the thermal zone's .get_temp() > callback resulting in an error causes the thermal core to print a > dev_warn() message to the kernel log which is super-noisy. > > To address this problem, make the core handle the case in which > .get_temp() returns 0, but the temperature value returned by it > is not actually valid, in a special way. Namely, make the core > completely ignore the invalid temperature value coming from > .get_temp() in that case, which requires folding in > update_temperature() into its caller and a few related changes. > > On the iwlwifi side, modify iwl_mvm_tzone_get_temp() to return 0 > and put THERMAL_TEMP_INVALID into the temperature return memory > location instead of returning an error when the firmware is not > running or it is not of the right type. > > Also, to clearly separate the handling of invalid temperature > values from the thermal zone initialization, introduce a special > THERMAL_TEMP_INIT value specifically for the latter purpose. > > Fixes: a8a261774466 ("thermal: core: Call monitor_thermal_zone() if zone temperature is invalid") > Closes: https://lore.kernel.org/linux-pm/20240715044527.GA1544@sol.localdomain/ > Reported-by: Eric Biggers <ebiggers@kernel.org> > Reported-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=201761 > Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> > Tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> > Cc: 6.10+ <stable@vger.kernel.org> # 6.10+ > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > > v1 -> v2: > * It is safer to retain the old behavior in thermal_zone_get_temp(), > which is the second place where the .get_temp() zone callback is > used, so make it return -ENODATA if the temperature value coming > from that callback is invalid. > * Add Tested-by: for Stefan. > > I have retained the previous Tested-by because the part of the patch that has > been tested remains unchanged. > > --- > drivers/net/wireless/intel/iwlwifi/mvm/tt.c | 7 +++ > drivers/thermal/thermal_core.c | 51 +++++++++++++--------------- > drivers/thermal/thermal_core.h | 3 + > drivers/thermal/thermal_helpers.c | 2 + > 4 files changed, 35 insertions(+), 28 deletions(-) This makes the log messages go away for me. However I had to resolve a conflict in drivers/net/wireless/intel/iwlwifi/mvm/tt.c to apply this patch to the latest upstream. - Eric
On Wed, Jul 17, 2024 at 11:24 PM Eric Biggers <ebiggers@kernel.org> wrote: > > On Wed, Jul 17, 2024 at 09:45:02PM +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > The iwlwifi wireless driver registers a thermal zone that is only needed > > when the network interface handled by it is up and it wants that thermal > > zone to be effectively ignored by the core otherwise. > > > > Before commit a8a261774466 ("thermal: core: Call monitor_thermal_zone() > > if zone temperature is invalid") that could be achieved by returning > > an error code from the thermal zone's .get_temp() callback because the > > core did not really handle errors returned by it almost at all. > > However, commit a8a261774466 made the core attempt to recover from the > > situation in which the temperature of a thermal zone cannot be > > determined due to errors returned by its .get_temp() and is always > > invalid from the core's perspective. > > > > That was done because there are thermal zones in which .get_temp() > > returns errors to start with due to some difficulties related to the > > initialization ordering, but then it will start to produce valid > > temperature values at one point. > > > > Unfortunately, the simple approach taken by commit a8a261774466, > > which is to poll the thermal zone periodically until its .get_temp() > > callback starts to return valid temperature values, is at odds with > > the special thermal zone in iwlwifi in which .get_temp() may always > > return an error because its network interface may always be down. If > > that happens, every attempt to invoke the thermal zone's .get_temp() > > callback resulting in an error causes the thermal core to print a > > dev_warn() message to the kernel log which is super-noisy. > > > > To address this problem, make the core handle the case in which > > .get_temp() returns 0, but the temperature value returned by it > > is not actually valid, in a special way. Namely, make the core > > completely ignore the invalid temperature value coming from > > .get_temp() in that case, which requires folding in > > update_temperature() into its caller and a few related changes. > > > > On the iwlwifi side, modify iwl_mvm_tzone_get_temp() to return 0 > > and put THERMAL_TEMP_INVALID into the temperature return memory > > location instead of returning an error when the firmware is not > > running or it is not of the right type. > > > > Also, to clearly separate the handling of invalid temperature > > values from the thermal zone initialization, introduce a special > > THERMAL_TEMP_INIT value specifically for the latter purpose. > > > > Fixes: a8a261774466 ("thermal: core: Call monitor_thermal_zone() if zone temperature is invalid") > > Closes: https://lore.kernel.org/linux-pm/20240715044527.GA1544@sol.localdomain/ > > Reported-by: Eric Biggers <ebiggers@kernel.org> > > Reported-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=201761 > > Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> > > Tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> > > Cc: 6.10+ <stable@vger.kernel.org> # 6.10+ > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > --- > > > > v1 -> v2: > > * It is safer to retain the old behavior in thermal_zone_get_temp(), > > which is the second place where the .get_temp() zone callback is > > used, so make it return -ENODATA if the temperature value coming > > from that callback is invalid. > > * Add Tested-by: for Stefan. > > > > I have retained the previous Tested-by because the part of the patch that has > > been tested remains unchanged. > > > > --- > > drivers/net/wireless/intel/iwlwifi/mvm/tt.c | 7 +++ > > drivers/thermal/thermal_core.c | 51 +++++++++++++--------------- > > drivers/thermal/thermal_core.h | 3 + > > drivers/thermal/thermal_helpers.c | 2 + > > 4 files changed, 35 insertions(+), 28 deletions(-) > > This makes the log messages go away for me. However I had to resolve a conflict > in drivers/net/wireless/intel/iwlwifi/mvm/tt.c to apply this patch to the latest > upstream. Thanks for the heads-up, I've rebased it on top of the current mainline while applying.
Index: linux-pm/drivers/thermal/thermal_core.c =================================================================== --- linux-pm.orig/drivers/thermal/thermal_core.c +++ linux-pm/drivers/thermal/thermal_core.c @@ -300,8 +300,6 @@ static void monitor_thermal_zone(struct thermal_zone_device_set_polling(tz, tz->passive_delay_jiffies); else if (tz->polling_delay_jiffies) thermal_zone_device_set_polling(tz, tz->polling_delay_jiffies); - else if (tz->temperature == THERMAL_TEMP_INVALID) - thermal_zone_device_set_polling(tz, msecs_to_jiffies(THERMAL_RECHECK_DELAY_MS)); } static struct thermal_governor *thermal_get_tz_governor(struct thermal_zone_device *tz) @@ -382,7 +380,7 @@ static void handle_thermal_trip(struct t td->threshold = trip->temperature; if (tz->last_temperature >= old_threshold && - tz->last_temperature != THERMAL_TEMP_INVALID) { + tz->last_temperature != THERMAL_TEMP_INIT) { /* * Mitigation is under way, so it needs to stop if the zone * temperature falls below the low temperature of the trip. @@ -417,27 +415,6 @@ static void handle_thermal_trip(struct t } } -static void update_temperature(struct thermal_zone_device *tz) -{ - int temp, ret; - - ret = __thermal_zone_get_temp(tz, &temp); - if (ret) { - if (ret != -EAGAIN) - dev_warn(&tz->device, - "failed to read out thermal zone (%d)\n", - ret); - return; - } - - tz->last_temperature = tz->temperature; - tz->temperature = temp; - - trace_thermal_temperature(tz); - - thermal_genl_sampling_temp(tz->id, temp); -} - static void thermal_zone_device_check(struct work_struct *work) { struct thermal_zone_device *tz = container_of(work, struct @@ -452,7 +429,7 @@ static void thermal_zone_device_init(str INIT_DELAYED_WORK(&tz->poll_queue, thermal_zone_device_check); - tz->temperature = THERMAL_TEMP_INVALID; + tz->temperature = THERMAL_TEMP_INIT; tz->passive = 0; tz->prev_low_trip = -INT_MAX; tz->prev_high_trip = INT_MAX; @@ -504,6 +481,7 @@ void __thermal_zone_device_update(struct struct thermal_trip_desc *td; LIST_HEAD(way_down_list); LIST_HEAD(way_up_list); + int temp, ret; if (tz->suspended) return; @@ -511,10 +489,29 @@ void __thermal_zone_device_update(struct if (!thermal_zone_device_is_enabled(tz)) return; - update_temperature(tz); + ret = __thermal_zone_get_temp(tz, &temp); + if (ret) { + if (ret != -EAGAIN) + dev_info(&tz->device, "Temperature check failed (%d)\n", ret); - if (tz->temperature == THERMAL_TEMP_INVALID) + thermal_zone_device_set_polling(tz, msecs_to_jiffies(THERMAL_RECHECK_DELAY_MS)); + return; + } else if (temp <= THERMAL_TEMP_INVALID) { + /* + * Special case: No valid temperature value is available, but + * the zone owner does not want the core to do anything about + * it. Continue regular zone polling if needed, so that this + * function can be called again, but skip everything else. + */ goto monitor; + } + + tz->last_temperature = tz->temperature; + tz->temperature = temp; + + trace_thermal_temperature(tz); + + thermal_genl_sampling_temp(tz->id, temp); tz->notify_event = event; Index: linux-pm/drivers/net/wireless/intel/iwlwifi/mvm/tt.c =================================================================== --- linux-pm.orig/drivers/net/wireless/intel/iwlwifi/mvm/tt.c +++ linux-pm/drivers/net/wireless/intel/iwlwifi/mvm/tt.c @@ -622,7 +622,12 @@ static int iwl_mvm_tzone_get_temp(struct if (!iwl_mvm_firmware_running(mvm) || mvm->fwrt.cur_fw_img != IWL_UCODE_REGULAR) { - ret = -ENODATA; + /* + * Tell the core that there is no valid temperature value to + * return, but it need not worry about this. + */ + *temperature = THERMAL_TEMP_INVALID; + ret = 0; goto out; } Index: linux-pm/drivers/thermal/thermal_core.h =================================================================== --- linux-pm.orig/drivers/thermal/thermal_core.h +++ linux-pm/drivers/thermal/thermal_core.h @@ -133,6 +133,9 @@ struct thermal_zone_device { struct thermal_trip_desc trips[] __counted_by(num_trips); }; +/* Initial thermal zone temperature. */ +#define THERMAL_TEMP_INIT INT_MIN + /* * Default delay after a failing thermal zone temperature check before * attempting to check it again. Index: linux-pm/drivers/thermal/thermal_helpers.c =================================================================== --- linux-pm.orig/drivers/thermal/thermal_helpers.c +++ linux-pm/drivers/thermal/thermal_helpers.c @@ -145,6 +145,8 @@ int thermal_zone_get_temp(struct thermal } ret = __thermal_zone_get_temp(tz, temp); + if (!ret && *temp <= THERMAL_TEMP_INVALID) + ret = -ENODATA; unlock: mutex_unlock(&tz->lock);