From: Filippo Falezza Reading the ath10k hwmon temperature sends WMI_PDEV_GET_TEMPERATURE and waits up to 5 s (ATH10K_THERMAL_SYNC_TIMEOUT_HZ) for the reply event, holding conf_mutex. Not all firmware answers: the WCN3990 firmware WLAN.HL.3.3.1-00694-QCAHLSWMTPLZ-1 on a Motorola Moto G 5G Plus codename nairo (SM7250) never sends the event, so every read of temp1_input stalls for 5 s, logs ath10k_snoc 18800000.wifi: failed to synchronize thermal read and returns -ETIMEDOUT. Tools that read all hwmon sensors, such as lm-sensors, hang for 5 s on every run, and configuration changes of the interface wait for conf_mutex in the meantime. Whether the firmware answers cannot be told from the chip: firmware that answers and firmware that does not both advertise WMI_SERVICE_THERM_THROT, and WCN3990 firmware differs between devices. Instead, remember that the running firmware did not answer, and return -EOPNOTSUPP right away on later reads. Forget it when the firmware starts, so that a restarted or updated firmware is asked again. The first read after each firmware start still takes 5 s when the firmware does not answer. Reads on firmware that answers are unchanged. This change was written with the help of an AI coding assistant; see the notes below. Fixes: e98199a8c27f ("ath10k: enable QCA6174/QCA9377 to read the chip temperature") Signed-off-by: Filippo Falezza --- Notes, not for the changelog: - Tool: Claude Opus 5.5 in Claude Code wrote the code and this changelog during an interactive bring-up session for the Moto G 5G Plus. The request was to fix `sensors` hanging on every run because of ath10k. A first version disabled the read for all WCN3990 through a hw_params flag; it was replaced by this one so that it does not assume all WCN3990 firmware behaves the same, as Loic Poulain asked of another WCN3990 firmware workaround ("ath10k: WCN3990 firmware workarounds for WLAN.HL.3.2", March 2026). - Tested on: Moto G 5G Plus (SM7250, WCN3990, firmware WLAN.HL.3.3.1-00694-QCAHLSWMTPLZ-1), linux-next next-20261021 plus device support patches, with this patch in place of a local WCN3990 quirk. First read of temp1_input: 5065 ms, -ETIMEDOUT, one warning; next reads: 8 ms, -EOPNOTSUPP; a full `sensors` run: 25 ms (5 s or more before). After switching Wi-Fi off and on, which restarts the firmware session, the first read waits 5 s again, then -EOPNOTSUPP. - Not tested: firmware that does answer the request (QCA6174, QCA9377, other WCN3990 firmware); for them only reads after a timeout change. Not run: sparse. - Build: W=1 for arm64, no warnings; checkpatch --strict clean. Applies to ath-next (cd026e68f). --- drivers/net/wireless/ath/ath10k/core.c | 1 + drivers/net/wireless/ath/ath10k/thermal.c | 9 ++++++++- drivers/net/wireless/ath/ath10k/thermal.h | 2 ++ 3 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c index 7c2939cbde5f..9467e4c3099a 100644 --- a/drivers/net/wireless/ath/ath10k/core.c +++ b/drivers/net/wireless/ath/ath10k/core.c @@ -2985,6 +2985,7 @@ int ath10k_core_start(struct ath10k *ar, enum ath10k_firmware_mode mode, clear_bit(ATH10K_FLAG_CRASH_FLUSH, &ar->dev_flags); ar->running_fw = fw; + ar->thermal.temperature_unanswered = false; if (!test_bit(ATH10K_FW_FEATURE_NON_BMI, ar->running_fw->fw_file.fw_features)) { diff --git a/drivers/net/wireless/ath/ath10k/thermal.c b/drivers/net/wireless/ath/ath10k/thermal.c index 9bb486f8e920..1079d552cff4 100644 --- a/drivers/net/wireless/ath/ath10k/thermal.c +++ b/drivers/net/wireless/ath/ath10k/thermal.c @@ -75,6 +75,12 @@ static ssize_t ath10k_thermal_show_temp(struct device *dev, goto out; } + /* Don't stall every read on firmware that never answers */ + if (ar->thermal.temperature_unanswered) { + ret = -EOPNOTSUPP; + goto out; + } + reinit_completion(&ar->thermal.wmi_sync); ret = ath10k_wmi_pdev_get_temperature(ar); if (ret) { @@ -90,7 +96,8 @@ static ssize_t ath10k_thermal_show_temp(struct device *dev, time_left = wait_for_completion_timeout(&ar->thermal.wmi_sync, ATH10K_THERMAL_SYNC_TIMEOUT_HZ); if (!time_left) { - ath10k_warn(ar, "failed to synchronize thermal read\n"); + ath10k_warn(ar, "failed to synchronize thermal read, not asking again until the firmware restarts\n"); + ar->thermal.temperature_unanswered = true; ret = -ETIMEDOUT; goto out; } diff --git a/drivers/net/wireless/ath/ath10k/thermal.h b/drivers/net/wireless/ath/ath10k/thermal.h index 1f4de9fbf2b3..cb930da5c04a 100644 --- a/drivers/net/wireless/ath/ath10k/thermal.h +++ b/drivers/net/wireless/ath/ath10k/thermal.h @@ -19,6 +19,8 @@ struct ath10k_thermal { /* protected by conf_mutex */ u32 throttle_state; u32 quiet_period; + /* the running firmware did not answer a temperature request */ + bool temperature_unanswered; /* temperature value in Celsius degree * protected by data_lock */ --- base-commit: cd026e68fdbf88b9cc522b76c7a9d92c9a41f709 change-id: 20261022-ath10k-temperature-22b119fd615c Best regards, -- Filippo Falezza