[PATCH v2] wifi: ath12k: restore country code during resume

[Baochen Qiang]

On 7/24/2026 8:15 AM, Jeff Johnson wrote:
> On 7/20/2026 5:09 AM, Stian Knudsen wrote:
>> The country code configured before suspend is lost after resume:
>> the device is powered down in suspend_late and powered back up in
>> resume_early, so firmware reboots with its default regulatory
>> settings and the previously set country code is no longer applied.
>>
>> On WCN7850 the firmware comes back in the world regulatory domain
>> (country 00) and takes ~7 seconds to rediscover the country code
>> from AP beacons, part of a ~16 second total delay before wifi
>> reconnects after resume.
>>
>> Restore it by resending WMI_SET_CURRENT_COUNTRY_CMDID during resume
>> if a country code was set before suspend, i.e. when ar->alpha2 is
>> valid. This follows the same approach as ath11k commit 7f0343b7b871
>> ("wifi: ath11k: restore country code during resume").
>>
>> Note that only single_pdev_only devices support suspend/resume (see
>> ath12k_core_continue_suspend_resume()), so handling the first and
>> only pdev is sufficient.
>>
>> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c7-00108-QCAHMTSWPL_V1.0_V2.0_SILICONZ_UPSTREAM-3
>>
>> Fixes: 8d5f4da8d70b ("wifi: ath12k: support suspend/resume")
>> Suggested-by: Baochen Qiang <baochen.qiang at oss.qualcomm.com>
>> Link: https://lore.kernel.org/r/-_iDJ_M5RrqACWB0qmtleg@pokerfj.es
>> Signed-off-by: Stian Knudsen <stian at pokerfj.es>
>> ---
>> v2:
>> - Add Fixes tag, per Baochen's review comment.
>> - Link to v1: https://lore.kernel.org/r/20260717130254.36732-1-stian@pokerfj.es
>> ---
>>  drivers/net/wireless/ath/ath12k/core.c | 21 +++++++++++++++++++++
>>  1 file changed, 21 insertions(+)
>>
>> diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
>> --- a/drivers/net/wireless/ath/ath12k/core.c
>> +++ b/drivers/net/wireless/ath/ath12k/core.c
>> @@ -197,6 +197,7 @@ EXPORT_SYMBOL(ath12k_core_resume_early);
>>
>>  int ath12k_core_resume(struct ath12k_base *ab)
>>  {
>> +	struct ath12k *ar;
>>  	long time_left;
>>  	int ret;
>>
>> @@ -211,6 +212,26 @@ int ath12k_core_resume(struct ath12k_base *ab)
>>  		return -ETIMEDOUT;
>>  	}
>>
>> +	/* So far only single_pdev_only devices can reach here,
>> +	 * so it is valid to handle the first, and the only, pdev.
>> +	 */
>> +	ar = ab->pdevs[0].ar;
>> +	if (ab->hw_params->current_cc_support &&
>> +	    ar->alpha2[0] != 0 && ar->alpha2[1] != 0) {
>> +		struct wmi_set_current_country_arg arg = {};
>> +
>> +		memcpy(&arg.alpha2, ar->alpha2, 2);
>> +
>> +		reinit_completion(&ar->regd_update_completed);
>> +
>> +		ret = ath12k_wmi_send_set_current_country_cmd(ar, &arg);
>> +		if (ret) {
>> +			ath12k_warn(ab, "failed to set country code during resume: %d\n",
>> +				    ret);
>> +			return ret;
>> +		}
> 
> Baochen, can you remind me why we don't need to wait for completion here?
> (the ath11k change doesn't wait)

Technically we will wait, but asynchronously instead of synchronously. It works in a way:

1. reinit completion
2. send new cc to firmware, proceed with no sync wait.
3. in reg channel list event host process reg rules, queue regd update work and signals
completion.
4. regd update work calls ath12k_regd_update() where we wait for the completion.

But I am feeling this is not a good design. As you can see, ath12k_regd_update() is
reachable via the regd update work, which is queued in reg chan list event. However it is
the event itself signals the completion. That means ath12k_regd_update() never blocks, the
whole reinit-wait thing is a no-ops.

> 
> If that is legit, perhaps we should document it with a comment since
> reinit_completion() without waiting for it seems strange
> 
>> +	}
>> +
>>  	return 0;
>>  }
>>  EXPORT_SYMBOL(ath12k_core_resume);
>> --
>> 2.50.0
>