Re: [Intel-wired-lan] [PATCH iwl-net v5] ice: fix missing dpll notifications for SW pins

[Jacob Keller <jacob.e.keller@intel.com>]

On 4/14/2026 12:16 PM, Michal Schmidt wrote:
> On 4/9/26 12:25, Petr Oros wrote:
>> ---
>>   drivers/net/ethernet/intel/ice/ice_dpll.c | 74 +++++++++++++++++++----
>>   1 file changed, 63 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/ice/ice_dpll.c b/drivers/net/
>> ethernet/intel/ice/ice_dpll.c
>> index 3f8cd5b8298b57..d817f17dcf1951 100644
>> --- a/drivers/net/ethernet/intel/ice/ice_dpll.c
>> +++ b/drivers/net/ethernet/intel/ice/ice_dpll.c
>> @@ -1154,6 +1154,30 @@ ice_dpll_input_state_get(const struct dpll_pin
>> *pin, void *pin_priv,
>>                         extack, ICE_DPLL_PIN_TYPE_INPUT);
>>   }
>>   +/**
>> + * ice_dpll_sw_pin_notify_peer - notify the paired SW pin after a
>> state change
>> + * @d: pointer to dplls struct
>> + * @changed: the SW pin that was explicitly changed (already notified
>> by dpll core)
>> + *
>> + * SMA and U.FL pins share physical signal paths in pairs (SMA1/U.FL1
>> and
>> + * SMA2/U.FL2).  When one pin's routing changes via the PCA9575 GPIO
>> + * expander, the paired pin's state may also change.  Send a change
>> + * notification for the peer pin so userspace consumers monitoring the
>> + * peer via dpll netlink learn about the update.
>> + *
>> + * Context: Can be called under pf->dplls.lock, dpll_pin_change_ntf()
>> is safe.
>> + */
>> +static void ice_dpll_sw_pin_notify_peer(struct ice_dplls *d,
>> +                    struct ice_dpll_pin *changed)
>> +{
>> +    struct ice_dpll_pin *peer;
>> +
>> +    peer = (changed >= d->sma && changed < d->sma +
>> ICE_DPLL_PIN_SW_NUM) ?
>> +        &d->ufl[changed->idx] : &d->sma[changed->idx];
>> +    if (peer->pin)
>> +        dpll_pin_change_ntf(peer->pin);
>> +}
>> +
>>   /**
>>    * ice_dpll_sma_direction_set - set direction of SMA pin
>>    * @p: pointer to a pin
>> @@ -1233,6 +1257,8 @@ static int ice_dpll_sma_direction_set(struct
>> ice_dpll_pin *p,
>>               ret = ice_dpll_pin_state_update(p->pf, target,
>>                               type, extack);
>>       }
>> +    if (!ret)
>> +        ice_dpll_sw_pin_notify_peer(d, p);
>>         return ret;
>>   }
> 
> ice_dpll_sma_direction_set() runs to process a DPLL_CMD_PIN_SET command
> from userspace. It runs with dpll_lock held - taken in dpll_pin_pre_doit().
> ice_dpll_sw_pin_notify_peer() -> dpll_pin_change_ntf() will take
> dpll_lock again and deadlock.
> 

Yep. I think you could use __dpll_pin_change_ntf() which is the version
that assumes the lock is held.. but that function is not exported
outside of drivers/dpll.

Either way, this needs to be fixed somehow before I can apply it.

Thanks,
Jake

> Michal
>