Re: [PATCH togreg v3 1/2] iio: imu: inv_icm42607: propagate runtime suspend errors

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 17 Aug 2026 17:32:43 +0800
Linmao Li <lilinmao@kylinos.cn> wrote:

> 在 2026/8/16 4:52, Jonathan Cameron 写道:
> > On Tue, 11 Aug 2026 18:33:00 +0800
> > Linmao Li <lilinmao@kylinos.cn> wrote:
> >  
> >> The runtime suspend callback always returns success even when updating
> >> PWR_MGMT0 fails. The PM core can then mark the device suspended while one
> >> or both sensors remain enabled.
> >>
> >> The sibling ICM-42600 driver propagates the corresponding
> >> inv_icm42600_set_pwr_mgmt0() failure from its runtime suspend callback.
> >> Make ICM-42607 follow the same behavior by returning the sensor shutdown
> >> error. Keep a void wrapper for the managed teardown action, where errors
> >> can only be logged.  
> > What is the practical affect of a sensor remaining enabled?  Bit of
> > power loss or something more significant?  This info matter when deciding
> > if we should rush this in during the rc phase, or wait for the next
> > merge window.  
> As far as I can tell, the practical effect is additional power
> consumption while the device is idle.  I found no corruption path, but I
> have no ICM-42607 hardware to reproduce the failure or measure the
> current.
> 
> It does not necessarily persist indefinitely.  If the PWR_MGMT0 write
> fails, regmap may contain the requested OFF state while the hardware
> remains ON.  A later sensor read requests an enabled mode, so
> inv_icm42607_set_pwr_mgmt0() retries the write instead of taking its
> "no change" return.  If the bus error was transient, the cache and
> hardware are then resynchronized.

Please capture some of that for the commit description for v2.

> 
> I also noticed a cost to this patch: returning an error such as -EIO from
> .runtime_suspend() makes the PM core set power.runtime_error. Subsequent
> reads then fail in PM_RUNTIME_ACQUIRE_AUTOSUSPEND() before any sensor
> register is accessed, until the PM status is reset.  A successful system
> suspend may clear that state.
> 
> The patch therefore trades a logged idle power leak that may recover on
> a later access for a potentially sticky runtime-PM failure.  Since this
> was found by inspection only, I would not rush it into the rc phase.  I
> would rather revisit the error handling and target the next merge window.
> 
That is fair enough.

J
> Linmao
> 
> >
> > Jonathan
> >
> >  
> >> Fixes: 3007c1530f96 ("iio: imu: inv_icm42607: Add PM support for icm42607")
> >> Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
> >> ---
> >> Unchanged since v1.
> >>
> >>   drivers/iio/imu/inv_icm42607/inv_icm42607_core.c | 15 ++++++++++-----
> >>   1 file changed, 10 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c b/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
> >> index 190e998f7b8ef..0da362967f63b 100644
> >> --- a/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
> >> +++ b/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
> >> @@ -537,9 +537,8 @@ static int inv_icm42607_enable_vddio_reg(struct inv_icm42607_state *st)
> >>   	return 0;
> >>   }
> >>   
> >> -static void inv_icm42607_sensors_off(void *_data)
> >> +static int inv_icm42607_sensors_off(struct inv_icm42607_state *st)
> >>   {
> >> -	struct inv_icm42607_state *st = _data;
> >>   	const struct device *dev = regmap_get_device(st->map);
> >>   	int ret;
> >>   
> >> @@ -552,6 +551,13 @@ static void inv_icm42607_sensors_off(void *_data)
> >>   					 st->conf.accel.mode);
> >>   	if (ret)
> >>   		dev_err(dev, "Unable to turn off sensors\n");
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static void inv_icm42607_sensors_off_action(void *data)
> >> +{
> >> +	inv_icm42607_sensors_off(data);
> >>   }
> >>   
> >>   static void inv_icm42607_disable_vddio_reg(void *_data)
> >> @@ -619,7 +625,7 @@ int inv_icm42607_core_probe(struct regmap *regmap,
> >>   	 * Ensure if sensors get turned on at some point, they're turned off
> >>   	 * as part of teardown.
> >>   	 */
> >> -	ret = devm_add_action_or_reset(dev, inv_icm42607_sensors_off, st);
> >> +	ret = devm_add_action_or_reset(dev, inv_icm42607_sensors_off_action, st);
> >>   	if (ret)
> >>   		return ret;
> >>   
> >> @@ -688,8 +694,7 @@ static int inv_icm42607_runtime_suspend(struct device *dev)
> >>   	 * however the tradeoff is that an unused sensor won't be
> >>   	 * turned off until the entire chip is no longer in use.
> >>   	 */
> >> -	inv_icm42607_sensors_off(st);
> >> -	return 0;
> >> +	return inv_icm42607_sensors_off(st);
> >>   }
> >>   
> >>   EXPORT_NS_GPL_DEV_PM_OPS(inv_icm42607_pm_ops, IIO_ICM42607) = {