On Fri, Jan 14, 2022 at 8:47 AM Benjamin Li <benl@xxxxxxxxxxxx> wrote:
>
> 'echo disabled > .../thermal_zoneX/mode' will disable the thermal core's
> polling mechanism to check for threshold trips. This is used sometimes to
> run performance test cases.
>
> However, tsens supports an interrupt mechanism to receive notification of
> trips, implemented in commit 634e11d5b450 ("drivers: thermal: tsens: Add
> interrupt support").
>
> Currently the thermal zone mode that's set by userspace is not checked
> before propagating threshold trip events from IRQs. Let's fix this to
> restore the abilty to disable thermal throttling at runtime.
>
> ====================
>
> Tested on MSM8939 running 5.16.0. This platform has 8 cores; the first
> four thermal zones control cpu0-3 and the last zone is for the other four
> CPUs together.
>
> for f in /sys/class/thermal/thermal_zone*; do
> echo "disabled" > $f/mode
> echo $f | paste - $f/type $f/mode
> done
>
> /sys/class/thermal/thermal_zone0 cpu0-thermal disabled
> /sys/class/thermal/thermal_zone1 cpu1-thermal disabled
> /sys/class/thermal/thermal_zone2 cpu2-thermal disabled
> /sys/class/thermal/thermal_zone3 cpu3-thermal disabled
> /sys/class/thermal/thermal_zone4 cpu4567-thermal disabled
>
> With mitigation thresholds at 75 degC and load running, we can now cruise
> past temp=75000 without CPU throttling kicking in.
>
> watch -n 1 "grep '' /sys/class/thermal/*/temp
> /sys/class/thermal/*/cur_state
> /sys/bus/cpu/devices/cpu*/cpufreq/cpuinfo_cur_freq"
>
> /sys/class/thermal/thermal_zone0/temp:82000
> /sys/class/thermal/thermal_zone1/temp:84000
> /sys/class/thermal/thermal_zone2/temp:87000
> /sys/class/thermal/thermal_zone3/temp:84000
> /sys/class/thermal/thermal_zone4/temp:84000
> /sys/class/thermal/cooling_device0/cur_state:0
> /sys/class/thermal/cooling_device1/cur_state:0
> /sys/bus/cpu/devices/cpu0/cpufreq/cpuinfo_cur_freq:1113600
> /sys/bus/cpu/devices/cpu1/cpufreq/cpuinfo_cur_freq:1113600
> /sys/bus/cpu/devices/cpu2/cpufreq/cpuinfo_cur_freq:1113600
> /sys/bus/cpu/devices/cpu3/cpufreq/cpuinfo_cur_freq:1113600
> /sys/bus/cpu/devices/cpu4/cpufreq/cpuinfo_cur_freq:800000
> /sys/bus/cpu/devices/cpu5/cpufreq/cpuinfo_cur_freq:800000
> /sys/bus/cpu/devices/cpu6/cpufreq/cpuinfo_cur_freq:800000
> /sys/bus/cpu/devices/cpu7/cpufreq/cpuinfo_cur_freq:800000
>
> Reported-by: Zac Crosby <zac@xxxxxxxxxxxx>
> Signed-off-by: Benjamin Li <benl@xxxxxxxxxxxx>
> ---
> Changes in v2:
> - Reordered sentences in first part of commit message to make sense.
>
> drivers/thermal/qcom/tsens.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
> index 99a8d9f3e03c..0b6299512e7c 100644
> --- a/drivers/thermal/qcom/tsens.c
> +++ b/drivers/thermal/qcom/tsens.c
> @@ -509,13 +509,16 @@ static irqreturn_t tsens_irq_thread(int irq, void *data)
> spin_unlock_irqrestore(&priv->ul_lock, flags);
>
> if (trigger) {
> - dev_dbg(priv->dev, "[%u] %s: TZ update trigger (%d mC)\n",
> - hw_id, __func__, temp);
> - thermal_zone_device_update(s->tzd,
> - THERMAL_EVENT_UNSPECIFIED);
> + if (s->tzd->mode == THERMAL_DEVICE_ENABLED) {
> + dev_dbg(priv->dev, "[%u] %s: TZ update trigger (%d mC)\n",
> + hw_id, __func__, temp);
> + thermal_zone_device_update(s->tzd, THERMAL_EVENT_UNSPECIFIED);
> + } else {
> + dev_dbg(priv->dev, "[%u] %s: TZ update trigger (%d mC) skipped as zone disabled\n",
Hmm. I don't like the fact that these messages won't be visible to
users in dmesg unless they're debugging. This change puts the SoC in a
potentially unsafe state. Perhaps we should print a ratelimited
message in the logs that we're operating outside safety limits?
> + hw_id, __func__, temp);
> + }
> } else {
> - dev_dbg(priv->dev, "[%u] %s: no violation: %d\n",
> - hw_id, __func__, temp);
> + dev_dbg(priv->dev, "[%u] %s: no violation: %d\n", hw_id, __func__, temp);
Get rid of this hunk, it is unrelated to the above change.
> }
>
> if (tsens_version(priv) < VER_0_1) {
> --
> 2.17.1
>
